Eocene Cliffs of Bournemouth Dorset
West, Ian M. 2016. The Eocene Cliffs of Bournemouth Dorset - Geology of the Wessex Coast. Internet site: www.southampton.ac.uk/~imw/Bournemouth-Geology.htm. New Version: 10th December 2016.

Bournemouth cliffs - geological field guide
Ian West,
Romsey, Hampshire

and Visiting Scientist at:
Faculty of Natural and Environmental Sciences
Southampton University,
Website hosted by iSolutions, Southampton University,

|Home and Contents | |Field Guides - Introduction |Sandbanks Peninsula |Brownsea Island, Poole Harbour |Hengistbury Head |Bibliography of the Geology of Hengistbury Head webpage. |Highcliffe, Barton & Hordle Coast Erosion |Highcliffe, Barton & Hordle Bibliography |Sandbanks Peninsula |Studland, South Haven Peninsula

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CONTENTS:

SECTION 1 - INTRODUCTION - GENERAL
1.1. INTRODUCTION - General
1.2. INTRODUCTION - Bournemouth Cliffs
1.3. INTRODUCTION - Bournemouth Chines
1.4. INTRODUCTION - Undercliff Drive
1.5. INTRODUCTION - Overcliff Drive

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SECTION 2 - INTRODUCTION - MAPS
2.1. INTRODUCTION - Topographic Maps
2.2. INTRODUCTION - Geological Maps
2.3. INTRODUCTION - Palaeogeographic Maps

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SECTION 3 - FORMATIONS [updated to 6th June 2016]
3.1 FORMATIONS - Introduction
3.2 FORMATIONS - Eocene Strata
3.3 FORMATIONS - Branksome Sand Formation
3.4 FORMATIONS - Branksome Sand Formation - River Channels
3.5 FORMATIONS - Branksome Sand Formation - Pyrite, Jarosite
3.6 FORMATIONS - Branksome Sand Formation - Seismites, Liquifaction
3.7 FORMATIONS - Boscombe Sand Formation - General (other topicsP
3.8 FORMATIONS - Boscombe Sand Formation -
3.9pb FORMATIONS - Boscombe Sand, Rounded, Battered Pebbles
[see also Boscombe Pier, further down]
3.10 FORMATIONS - Eocene Palaeogeography
3.11 FORMATIONS - Eocene MECO - Middle Eocene Climatic Optimum
3.12 FORMATIONS - Pleistocene Strata (flint gravels)
3.13 FORMATIONS - Pleistocene Strata (for further notes)
3.14 FORMATIONS - [extra for future use]

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SECTION 4 - FOSSILS
4.1 FOSSILS - Introduction
4.2 FOSSILS - Marine Shells
4.3 FOSSILS - Plant Fossils
4.4 FOSSILS - Plant Fossils - Palaeoclimatic Implications of Bournemouth Eocene Flora.

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SECTION 5 - SEDIMENTOLOGY
5.1 SEDIMENTOLOGY - Introduction
5.2 SEDIMENTOLOGY - Clay Mineral Distribution -
5.3 SEDIMENTOLOGY - Sedimentary Structures, General
5.4
SEDIMENTOLOGY - Liquifaction

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SECTION 6A - GEOMORPHOLOGY
6.A1 6.A1 GEOMORPHOLOGY INTRODUCTION

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SECTION 6B - BEACH AND BEACH PROCESSES

6.B1 6.B1 BEACHES INTRODUCTION
6.B2.
6.B2 BEACHES - Sand Replenishment (renourishment)
6.B3 6.B3 BEACHES - Loss of Beach Sand -

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SECTION 7 - LOCATIONS [BOURNEMOUTH]
7.0 LOCATION - Sandbanks Peninsula
7.1 LOCATION - Canford Cliffs
7.2 LOCATION - Branksome Chine
7.2a LOCATION - Branksome Dene Chine
7.3 LOCATION - Alum Chine
7.4 LOCATION - Durley Chine
7.5 LOCATION - West Cliff and Lift
7.6 LOCATION - Bournemouth Pier
7.7 LOCATION - East Cliff - General - Bournemouth to Boscombe Piers
7.7a LOCATION - East Cliff - Bournemouth to Boscombe Piers - Sulphide Oxidation in the Boscombe Sands.
7.7b LOCATION - East Cliff - Bournemouth to Boscombe Piers - Upward Movement of Piles with Groynes.
7.7c LOCATION - East Cliff - Liquifaction and Seismite Structures
7.8
LOCATION - East Cliff Lift Area
7.9 LOCATION - Approaching Boscombe Pier from the West
7.10 LOCATION - Boscombe Pier
7.10a LOCATION - Boscombe Pier - Ancient battered pebbles
7.11 LOCATION - Honeycombe Chine
7.12 LOCATION - Honeycombe Chine to Southbourne
7.13 LOCATION - Southbourne
7.13a LOCATION - Southbourne Coast Erosion
7.14 LOCATION - Hengistbury Head

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SECTION 7x. PETROLEUM LICENCE BLOCKS (BOURNEMOUTH)

7X. [Extra - 2016] PETROLEUM EXPLORATION AT OR NEAR BOURNEMOUTH (including: New licence blocks in the Bournemouth area)

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SECTION 8. LANDSLIDES AND CLIFF FALLS

8.1 LANDSLIDES - Introduction
8.2 LANDSLIDES - East Cliff - 2014 (Just west of East Cliff Lift)
8.3 LANDSLIDES - East Cliff - 2016 - Introduction
8.4 LANDSLIDES - East Cliff - 2016 - Advance Warning - Evidence
8.5 LANDSLIDES - [for future use]

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9.1 ACKNOWLEDGEMENTS

9.2 BIBLIOGRAPHY AND REFERENCES

[END OF CONTENTS SO FAR - INCOMPLETE 21st August 2016.

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INTRODUCTION

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SECTION 1 - INTRODUCTION - GENERAL

1.1 INTRODUCTION - 1 General

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Palaeovalleys of Velegrakis et al. 1999 in Poole and Christchurch Bays

Poole Bay, off Bournemouth is a very new feature, very youthful indeed, probably only a few thousand years old. It is a flooded river valley system, part of the pattern of rivers that flowed down the dry site of the English Channel to join the extension of the River Seine. Even the Bourne stream from which Bournemouth takes its name is really a trivial, former tributary of the great French river. This is the real situation, but it is not seen by the public in this way. It is probable that they think of it as a permanent place, not somewhere at the margin of an expanding shallow sea. Fortunately there is no real problem with this, but humans live on a very short time scale and they hardly notice slow entension of the sea, only being surprised by occasional dramatic events, like great hurricanes and tsunamis. In this southern England region these rarely occur within human lifetimes, but are not impossible.

Away from the geological viewpoint, Bournemouth is a pleasnt popular holiday town on the south coast of England (it is well known to the present writer who lived there and attended Bournemouth School). The town owes its attraction to visitors to the former presence of yellow sandy cliffs of Eocene strata with beaches of sand originally derived from these cliffs. Unfortunately, so to reduce cliff falls, the once-yellow cliffs have now been covered for the most part in vegetation. Howwever, some, still-exposed sandy parts of the cliff remain, especially away from the crowded area near Bournemouth Pier. During the second world war, barbed wire prevented much access except for a short distance on either side of Bournemouth pier. The beach was supposedly mined against a possible German invasion and Bournemouth and Boscombe piers had both been intentionally blown apart with large gaps in the middle. The continuous anti-tank scafolding was a major feature of the Bournemouth coast during the war and for some time afterwards. German planes were only occasionally seen close by. Until the late 1950s the sewage was a problem on the beaches of Bournemouth. There was a direct sewage outfall as at most other places (including Bondi Beach). Here it was south of Bournemouth Pier, and thus the contamination widespread to the east, as far as Southbourne. However, in the 1960s the sewage problem was dealt with and local protests ceased.

This was the non-geological background to Bournemouth in recent years. Earlier there had been much valuable collecting of fossil plants. However, from the 1950s onwards, there was not much access to exposures. However, Barton-on-Sea, with abundant fossils is only a short distance from Bournemouth so that was inevitably the local, attractive geological area to visit. Nearer to Bournemouth, Hengistbury Head does not have calcareous shell fossils preserved but it was always notable for fossil sharks teeth. There are rare, hollow moulds of fossil mollusc shells in certain of the ironstone nodules, although only a small number of nodules are visible now.

A general view of Bournemouth Pier, Bournemouth, Dorset, and the re-nourished sandy beach, as seen from a helicopter, 6th July 2013

The cliffs between Middle Chine and Bournemouth Pier, Bournemouth, Dorset, 6th July 2013, helicopter view

View towards Bournemouth Pier, Dorset, from west of Branksome Chine, showing largely vegetated, Eocene cliffs and a broad sandy beach

Cliffs of Bournemouth, Dorset, seen from Sandbanks

View of Bournemouth Pier from Boscombe Pier, late on a winter's day, showing wide sandy beaches and timber groynes

Poole Head from Sandbanks with Eocene cliffs beyond, Dorset

Branksome Sand at Canford Cliffs, west of Branksome Chine, Dorset

A view of Bournemouth in its early days of development and when the cliffs were still a natural source of supply of sand and gravel to the beaches and not shut off by a seawall and promenade

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1.2 INTRODUCTION - 2 - Bournemouth Cliffs

Poole Head from Sandbanks with Eocene cliffs beyond, Dorset

The Bournemouth Cliffs and the Sandbanks Peninsula are part of Poole Bay, a broad shallow embayment on the central south coast of England. It is mostly a area of sandy beaches and, although occasionally the sea can be in stormy condition as shown in the right photograph, the coast is protected to some extent from the prevailing southwesterly winds by the promontories of the Isle of Purbeck, particularly that of Old Harry Rocks and Ballard Point (visible here). The Bournemouth cliffs (left photograph) are notable for sands and clays of Eocene age and in which some remarkable plant fossils have been found. Until about the beginning of the 19th century these cliffs were well-exposed, attractive yellow cliffs which supplied sand directly to the Bournemouth beaches. This area then became heavily developed and expanded into the present holiday town. A consequence of the development was the construction of a promenade and sea-wall which now covers the base of the cliffs. With lack of erosion are now quite largely vegetated and they are controlled and drained by civil engineering works. Although most of the cliffs are now generally inaccessible for detailed geological studies, some features of interest can still be seen. It is well-worth taking a walk along the foot of the cliffs and considering the geology. Furthermore an extension of this coast in relatively natural form still exists not far to the east at Hengistbury Head , described in a separate webpage. At the other (western) end of the bay, and at the entrance to Poole Harbour, is the |Sandbanks peninsula, once a sand-dune-covered sand spit, but now developed for expensive housing. The beach is of interest here and the rock groynes have relics of fossil trees, stromatolites and other fossils and structures from the Purbeck and Portland strata of the Isle of Portland, the source of the rocks. From Sandbanks there is a ferry across the narrow entrance to the natural and undeveloped Studland or South Haven Peninsula , also described in a separate webpage. This is a classic area for geomorphological and environmental studies.

Knowledge gained from the Bournemouth cliffs is of great interest and is relevant to understanding the geology of the Eocene strata in the region. In historic times the Bournemouth cliffs were once used for mining of copperas (alum-type sulphate minerals) because of the pyrite content. They are most famous, though, for their fossil leaves which seem to indicate that in Eocene times there was here an unusually warm environment even thought the palaeolatitude would normally suggest temperate rather tropical conditions .

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1.3 INTRODUCTION - 3 - Bournemouth Chines

The Chine of Bournemouth are well known. These are steep sided small valley on the coast. The word comes from Saxon "Cinan" meaning a gap or yawn (Wikipedia). If the origin of the name is Saxon then it is an indication these coastal geomorphological features are quite old in historical time. Of course they are very new in geological time!

These small coastal valleys are developed in easily and quickly eroded sands and clays. At Bournemouth they are in Eocene strata. In the Isle of Wight they are present in both Eocene and Cretaceous, particularly Wealden and Lower Greensand cliffs. Characteristically they contain a small stream or rivulet which is adjusted at its mouth to the present beach level. Thus they are convenient access routes to the shore without having to descend steep cliffs. Although many are still in this form, particularly at Bournemouth, where there is a sea-wall and promenade, others have been eroded back into hanging valleys. This erosion and eventual destruction is most marked on the southwest coast of the Isle of Wight where there is rapid coast erosion. It is high there because the weak coast faces southwesterly wind and wave action. As a result access to that coast is now becoming increasingly difficult. Thus it should be noted that on exposed coasts with rapid erosion chines are not keeping pace and are progressively being lost. They are probably not, therefore, as was argued by Bury (1934) the result of rapid coast erosion. They may have formed in a pause following rapid coast erosion.

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The chines of Bournemouth from west to east are as follows:

(Poole Head)

Flaghead Chine
(there was a watch tower on cliff top on the east side)

Canford Cliff Chine
(In 1882 this was Sugar-Loaf Chine, named after a large conical hummock, resembling an old fashioned sugar-loaf).

Branksome Chine (present name)
(but this was Branksome Glen or Watering Chine in 1882)

Branksome Dene Chine
(listed as Branksome Chine in 1882)

Alum Chine
(Listed as Alum Chine or Broad Chine in 1882)

Middle Chine

Durley Chine
(Great Durley Chine in 1882)

Little Durley Chine - no longer exists.
(in 1882, shown as a shallow indentation, and probably at the site of the present cliff path or the lift)

(Flag Staff on the cliff top in 1882)

The Bourne Valley.
At Bournemouth Pier - a long stream valley, not a true "chine".
(There is Head, peat deposits and a submerged forest of carbonised wood, under the pier approach. The Bournemouth Pier peat deposit and submerged forest contains stumps of pine, together with birch and alder (White, 1917). It lies on gravel, presumably Pleistocene. It is most likely to be of about Neolithic age, but it could be older. It shows that the Bourne Valley is not a recent "chine" but a stream valley with a long history.)

Step Chine (no longer present)
(this was a small recess at the cliff path or zigzag not far to the east of Bournemouth Pier).

Boscombe Chine (major chine)

Honeycomb Chine (no longer exists)
(This was a short distance east of Boscombe Chine. It was a small, picturesque, chine, a shallow indentation, with a honeycomb-like structure. It was notable for abundant fossil remains of Nipa, the Vietnam Swamp Palm in the Eocene strata.)

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The Pleistocene palaeovalleys made by rivers flowing across Poole Bay and Christchurch Bay, English Channel, modified after Velegrakis et al. 1999

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In general the chines probably commenced as minor upper tributaries of the original offshore continuation of the Branksome Chine stream and the Bourne Stream which would have headed generally south in the direction of a former river channel in Poole Bay. See See Velegrakis et al., (1999), and a sea-floor map, based on that work, and which is reproduced in another part of this webpage. The small streams of particular chines were heading for either Palaeovalley Complex 2, flowing south directly south of Bournemouth or Palaeovalley Complex 1, ie. the Piddle - Frome extension (coming out of Poole Harbour).

In contrast, in the old accounts the chines were wrongly regarded as the upper parts of former tributaries of the Solent River. See, for example, Bury (1934). However, new evidence shows that there was actually no eastern flowing Solent River immediately to the south of Bournemouth in the late Pleistocene (although there might have been at an earlier date). The Solent River was not there and there is no fossil channel of an eastward flowing river at a geologically recent date, i.e. at the time just before the chines were formed.

Bury (1934) commented on the supposed early history of the chines. Although, cautious now about his older view about the Solent River, we can consider his other aspects of his discussion.

"The rate of regression of the shore-line [at Bournemouth] has probably varied from time to time, but at the end of the last century, before the erection of the present sea walls, it amounted to about 9 inches [23 cm] per annum at the western end of the bay [Branksome, Canford Cliffs etc.] to about two and a half feet (76 cm) per annum at Southbourne [i.e. fast like Barton-on-Sea]. This advance of the sea necessarily shortened the valleys, and compelled the streams in them to cut their beds down to lower levels and steeper gradients; and it is this comparatively rapid adjustment to changing conditions which has led to the formation of the ravine-like chines."

It is true that a phase of rapid coastal erosion was probably the starting point for the development of the chines. The ends of the small streams became closer to their head because of coast erosion. The gradient of part of the stream had to change. It did this by the formation of a new knickpoint, i.e. the thalweg changed because of a phase of rapid coastal retreat.

However, if the coastal retreat is very rapid the stream cannot adjust to sea-level. This is happening of the southwest coast of the Isle of Wight where there are chines cut into Wealden strata. Rapid coast erosion produces hanging valley, and in due course chines are completely lost. This is common in many places with soft rock, but at Bournemouth there has been is a sea-wall and promenade since 1914. Thus the chine situation at Bournemouth is, in a sense, fossil. The coast has not retreated since 1914. Prior to that date there had to be a phase of rapid coast erosion. However, there also had to be a subsequent pause in coastal retreat so as to allow downcutting at the chines. In this respect I would disagree with the old theory of Henry Bury.

So the general pattern is rapid coast erosion, then a pause in coastal retreat. Chines then develop. If a new phase of rapid coast erosion occurs then, as on the Isle of Wight now, the chines are eroded away. They become hanging valleys, finally almost disappearing. Access to the coast is thus greatly reduced. This is current situation, except at Bournemouth where old the sea wall and promenade still survive (due to protection by the Isle of Purbeck from the worst effects of southwesterly storms)

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1.4 INTRODUCTION - 4 - The Undercliff Drive (East).

View from the East Cliff Zigzag of the Undercliff Drive, East, Bournemouth, Dorset, in the 1920s, when there were still horse-drawn carriages on this road

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The Bournemouth East Cliff and Undercliff Drive at Easter 1933, modified by Ian West

The photograph above shows, near Bournemouth Pier, some human crowd behaviour of the 1930s, and human crowd tolerance, some rather different from what would be expected today. The cliffs are not shown clearly but are generally rather similar to their present situation, although with rather better exposure. For more historic photographs of the Undercliff Drive, Bournemouth, see:
Graces Guide to British Industrial History, Undercliff Drive, Bournemouth section. This has a good set of photographs from 1914.

Regarding the history of the East Undercliff Drive, the local gentry were involved. Sir Merton and Lady Russell-Cotes were the founders of the Russell Cotes Art Gallery and Museum. Merton Russell-Cotes and Annie Nelson Clark were both born in 1835. They married in 1860 and started their married life in Dublin where they lived for 16 years. In lalter years, in Bournemouth they lived at what is now the Russell-Cotes Museum on the east cliff top. They were much involved with the opening of the Undercliff Drive, particularly in 1907, and effectively with the destruction of an important geological site. The drive or wide promenade was built directly at the foot of the cliffs. There is no gap for cliff fall debris between the Undercliff Drive, effectively a road between Bournemouth and Boscombe Piers, and the cliff. This means that when there is a cliff fall, the debris cannot be left. So the removal of the bottom debris of a landslide takes place. This is, of course, a foolish procedure, because the relative stability provided by the debris is lost. The cliff is effectively made ready for another cliff fall. This unwise procedure has been criticised in the past, but it seems unlikely that there will be any change in policy. The Undercliff Drive is in regular use for certain vehicles, including council vans and trucks. A land-train now uses the Undercliff Drive and there is always some small risk to this from cliff-falls or landslides. Even though no accident has happened, one cannot be content that the place is perfectly safe.

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1.5 INTRODUCTION - 5- Overcliff Drive (East).

There is not much special geological significance regarding the Overcliff Drive between Bournemouth and Boscombe. It is largely on Pleistocene Gravel Terrace 10 (about 2 or 3 metres of subangular flint gravel) or on blown sand overlying the gravel terrace. The blown sand deposits are thin and result from the wind blowing sand up from the cliff face. A similar situation exists for the road on the overcliff further east, towards Southbourne. Beneath the Quaternary gravel deposits are Eocene sands and clays, with the Boscombe Sand Formation overlying the Branksome Sand Formation. See the British Geological Survey Map, England and Wales Sheet 329, Solid and Drift Edition, 1991 for details.

A local problem regarding the Overcliff Drive might arise in the vicinity of the East Cliff Lift. There has been a landslide here and the cliff is left quite steep (and vertical at the top). It might or might not be necessary to cut back the cliff top in a limited area. This might affect part of the road, although major changes are not anticipated.

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SECTION 2 - INTRODUCTION - MAPS

2.1 INTRODUCTION - 1- Topographic Maps.

The main topographic map of the area of interest for general purposes is: Ordnance Survey, Landranger Map 195. Bournemouth and Purbeck (Wimborne Minster and Ringwood), 1:50,000 Scale. 2009. The area from the east in a direction westward to 1km. beyond Boscombe Pier is also shown on the 1:25,000 Ordnance Survey, Outdoor Leisure Map, New Forest, 1:25,000. Both of the above maps are easily obtained.

Amongst various older maps, note that the one inch to one mile Ordnance Survey, New Forest, Tourist Map (revised 1968-1970 with selected roads, revised to 1976). There are also various older, large-scale maps, such as the six inch to one mile maps, which are less readily obtained, but can be with some searching on the internet. Some Admiralty Charts include the Bournemouth and Poole Harbour area.

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2.2 INTRODUCTION - 2 - Geological Maps.

The 1891 version of the geological map of Bournemouth, Dorset, with additional notes

The main geological map for the Bournemouth area is the British Geological Survey (BGS) Sheet England and Wales, No. 329, Bournemouth, 1:50,000 Series, Solid and Drift Edition, NERC 1991. It is not expensive and is easily and quickly obtained online from BGS. It has horizontal sections and vertical sections given beneath the map. I also use the 1947 edition: Geological Survey of England and Wales, Bournemouth, Sheet 329, one inch to one statute mile. It does not differ greatly from the modern map, but shows less detail and uses older terminology. It of interest in that the old base map is of 1893 and there are interesting historic aspects. For example three piers, not two piers are shown at Bournemouth. The third one is Southbourne Pier. There are no cliff lifts and no Undercliff Drive. The London and Southwestern Railway comes south from Fordingbridge but the Brockenhurst - Christchurch line is in existence. The Bournemouth Branch Line goes to Bournemouth Station. A major difference in terms of geology is that the particular Pleistocene gravel terraces are not differentiated on the old map, apart from Plateau Gravel and Valley Gravel, whereas on the new map the terraces are numbered. It is mostly (high) Terrace 10 that is above the Bournemouth Cliffs. Rapid coast erosion with the transgression of the English Channel explains why an old, high terrace caps the Bournemouth cliffs.

For offshore geology, shown on a fairly small scale map see: Carte Geologique de La Manche: Geological Map of the English Channel. 1:1000000. Bureau de Recherches Geologique et Minieres, Service Geologique National. 1974. It is a good, colour, introductory map by Gilbert Boillot and Jean-Pierre Lefort. For more detail, offshore, in the Bournemouth area, see the British Geological Survey, Wight, Sheet 50 degrees N - 2 degrees W, 1: 250,000 Series, Solid Geology, Second Edition. Much more detail, regarding the offshore area is in the possession of the British Geological Survey. See also the large quantity of important technical data that is held by the Channel Coastal Observatory.

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2.3 INTRODUCTION - 3 - Palaeogeographic Maps.

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A general palaeogeographic map of the English Channel and broader European area in the Middle Eocene, Lutetian (about 41 million years ago) is shown below. Notice that a precursor of the English Channel was already present at this relatively early date.

A small-scale palaeogeographic map for New Forest National Park and the Hampshire, Dorset, Isle of Wight coastal exposures of the Lutetian, middle Eocene strata

The palaeogeographic map above is based on Diedrich (2012). It is generalised but it sets the scene. The New Forest and the Hampshire and Dorset coastal exposures and those of the Isle of Wight contain deposits that originated in a warmer precursor of the English Channel. Regard the comments about beach pebbles with caution at the moment. It is not impossible that the wave action responsible for these "Chesil Beach" type clasts may have been coming from the southwest, even in spite of early uplift of the Isle of Wight structures.

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The more specific local palaeogeography is now shown in a modified version of a map, based on the work of Plint (1983). This has been modified to some extent, but it is intended to show the palaeogeography in the Middle Eocene, near the MECO, the Middle Eocene Climatic Optimum. The conditions were very warm, indeed warm enough for the Vietnam Swamp Palm, Nipa, the fruits of which are abundant at Boscombe near Bournemouth. The environment was too wet for evaporites, although traces of these are found near the end of the Eocene in the Isle of Wight. Major Eocene evaporites occur in the Paris Basin.

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A speculative palaeogeographic map for the Middle Eocene, about the MECO time, for the Bournemouth and Hampshire Basin area, based on Plint (1983) but with modifications

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FORMATIONS

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SECTION 3 - FORMATIONS (Stratigraphy)

3.1 FORMATIONS - 1 - Introduction

The pre-Pleistocene strata exposed in the Bournemouth Cliff are entirely Eocene in age, and this is not a disputed point. There is not necessarily full agreement about the particular parts or particular boundaries of the Eocene which are exposed at Bournemouth. In broad terms the strata dates from about the middle of the Eocene.

The strata seen in the cliffs of Bournemouth is entirely of Eocene age, except for a thin (2 or 3 metre) overlying sheet of Pleistocene flint, river gravel. The discussion here is only with regard to the Eocene strata. The main units seen in the cliffs are as follows:

Branksome Sand Formation (above)

Boscombe Sand Formation (below)

Both of these, but particularly the Branksome Sand Formation contain beds and channel deposits of clay with lignite and pyrite.

Branksome Sand Formation [subheading of FORMATIONS-1]

The age and correlation of the Branksome Sand Formation is a matter of discussion and disagreement. Diagrams here have been prepared at different dates. In the past, the unit was regarded as belonging to the Bracklesham Group. There is some evidence now that it is actually the equivalent of the basal part of the Barton Clay Formation elsewhere (Isle of Wight particularly) and if so it is Bartonian and not Lutetian or Auversian. In most older diagrams of this webpage it is listed as Bracklesham, but in some later diagrams it is classified as Bartonian. If this is firmly proven, and when time permits, the diagrams will be changed so that the Branksome Sand Formation is listed as equivalent to the basal part of the Barton Clay Formation (but not that at Barton-on-Sea, where the clay may commence at a higher level). Lateral facies changes are not unexpected because of the occurrence in the west of the basin of the Poole Delta and its associated rivers bringing in clastics from the west.

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A chart showing lithostratigraphic schemes for the Palaeogene strata of the Bournemouth and Poole area, including Brownsea Island and Barton-on-Sea

The Branksome Sand Formation overlies the Poole Formation (mostly seen further west). It is about 70 metres thick and named after Branksome Chine [SZ 069 090], some way to the west of Bournemouth Pier [at one time, in my schoolday, this was at almost the eastern part of Dorset, and Bournemouth was part of Hampshire. It crops out in a 5km. wide arc from Ferndown in the north, through Parley, the northern part of Bournemouth and the Branksome area of Poole, to Brownsea Island in the west (Bristow et al., 1991). The base of the formation is taken as a transgessive erosion surface at the top of the Parkstone Clay or its underlying sand. The Branksome Sand Formation consists of eight fining-upward cycles, in which the upper seven were lettered A to G in ascending order by (Plint, 1983b).

The average grain size of the sand of the Branksome Sand Formation is medium - 253 microns but ranges from coarse to very fine. It is in general, moderately sorted (although varying) and slightly positively skewed.

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3.2 FORMATIONS - 2 - Eocene Strata - General

The main strata visible in the Bournemouth Cliffs are Eocene sands and clays, of marine or deltaic origin. These are in age, round about 41 million years old. The sands are not usually cemented into a hard rock, but they can be a firm sandstone in some cases. Generally they are weak sandstones, so poorly cemented, that if disturbed they easily collapse. These strata, do not normally contain marine fossil shells. This is partly because they are not generally of open sea origin, but wered deposited in marginal deltaic conditions, where sea water from the main Hampshire Basin to the east was in contact with deltaic sediments, including much fossil wood, present as black lignite. The rivers coming in from the west brought down much other plant debris, building up leaf beds in places. The main delta was situated in the Poole Harbour area. The shallow sea sediments with abundant fossil shells are best seen at Bracklesham Bay and the Selsey Peninsula, and on the Isle of Wight, particularly at Whitecliff Bay. So Bournemouth is disappointing to the fossil collector after fossil shells but it is a place of much interest to the palaeobotanist. The sedimentology is very interesting and for this subject, reference should be made to the works of Plint, given in the reference list below.

Fossiliferous strata can be seen at Hengistbury Head to the east. For this locality go to a separate webpages at:
|Hengistbury Head. See also |Bibliography of the Geology of Hengistbury Head webpage.
In the other direction (i.e. west or southwest) see the related webpage on the:
|Sandbanks Peninsula

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3.3 FORMATIONS - 3 - Branksome Sand Formation - Introduction

[Notes to be added]

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3.4 FORMATIONS - 4 - Branksome Sand Formation - River Channels

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River Channel Plugs of the Poole Delta

Part of channel plug of the Poole Delta in the upper part of the Branksome Sands, East Cliff, Bournemouth, Dorset, 8th March 2014

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Common features of the Branksome Sands, especially the upper part, just the Boscombe Sands, are channel plugs. These are the laminated, sandy clay infills of the channels on the Poole Delta. This is late in its history and it was becoming inudated by the sea from time to time. The part of the delta in the Bournemouth cliffs was behind the beaches in late Bracklesham times. It was not until early Bartonian times that the pebbles of the great storm beaches were driven over it in a westward direction. These delta channels were generally foul and stagnant, causing deposition of pyrite. At times though, marine water entered and occasional marine shells and sharks teeth have been found in them. There are even Teredina borings so palaeosalinity was then suitable for marine life. Sometimes, though the channels were abandoned and ended with aquatic plants living in their swampy environments. See Plint (1983b), Gardner (1987b) and Bristow et al. (1991).

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3.5 FORMATIONS - 5 - Branksome Sand Formation - Pyrite, Jarosite etc.

[Notes to be added]

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3.6 FORMATIONS - 6 - Branksome Sand Formation - Seismites, Liquifaction.

[Notes to be added]

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3.8 FORMATIONS - 8 - Boscombe Sand Formation

[Notes to be added]

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3.9pb FORMATIONS - 9 - Boscombe Sand Formation - Rounded, Battered Flint Pebbles

[For details, go to subsection:
Boscombe Pier (click from index - see 3.9)

or more specifically:
Boscombe Pier - An ancient Chesil Beach ]

A remarkable feature of the Bournemouth Cliffs and at some other places is the occurrence of very rounded flint pebbles from the Chalk. These have been battered on a beach like the Chesil Beach. They are found at Boscombe, Hengistbury Head, Studley Wood (reworked into Pleistocene) in the New Forest and at other places. They correspond to an initial phase of erosion of the Chalk at the northern Isle of Wight, at the time of its initial uplift in the early Bartonian. Great storm waves were coming from the east at this time and eroding pebbles from Maastrichtian Chalk which is no longer preserved on the Isle of Wight. Please go to the section referred to above for more details.
[Notes to be added]

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3.9 FORMATIONS - 9 - Eocene Palaeogeography

[Notes to be added]

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3.10 FORMATIONS - 10 - Eocene Palaeogeography

[Notes to be added]

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3.11 FORMATIONS - 11 - Eocene MECO

Eocene MECO [Middle Eocene Climatic Optimum]

The MECO, Middle Eocene Climatic Optimum seems to have has some effects of Eocene sedimentation and palaeogeography in the Bournemouth, New Forest and Isle of Wight area. The Middle Eocene Climatic Optimum, round about 40 million years ago (41.5 according to some authors) is almost certainly represented by some aspects of the middle Eocene strata of the Bournemouth Cliff. The matter is not gone into in any extensive manner here. It is just mentioned with some speculation about the precise horizon deposited during this thermal event. Further notes may be added later.

The MECO, Middle Eocene Climatic Optimum, time plane, shown in speculative manner for Studley Wood, Barton-on-Sea and other New Forest and Bournemouth regions

MECO - Middle Eocene Climatic Optimum - Some Brief Notes.
The Middle Eocene Climatic Optimum (MECO) is an enigmatic global warming event interrupting the protracted Cenozoic cooling. It is marked by a negative shift in marine oxygen isotope records that indicate an increase of water temperatures by up to 5 to 6 degrees C and thus, documents an increase in temperatures on top of the warm Eocene climate. This makes the MECO one of the hottest phases during Earth's climate history, but the questions, if and how the MECO affected continental sites are still unresolved. - extract from:
It's getting hot on Earth - The Middle Eocene Climatic Optimum in a terrestrial sedimentary record. 2013 By K.M. ETHNER, U.W ACKER, J.F. IEBIG, A.M ULCH and C.P.C. HAMBERLAIN. Goldschmidt2013 Conference Abstracts. Available online.] [Further notes on this topic will be added]

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3.11 FORMATIONS - 12 - Pleistocene Strata

Pleistocene flint gravels form a few metres of capping to the cliffs. These clasts are subangular and generally unlike the rounded Eocene flints, although some Eocene examples may be reworked into the Pleistocene gravels.

[Further notes to be added]

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3.7 FORMATIONS - 7 - [Eocene, - ready for future use]

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3.8 FORMATIONS - 8 - Pleistocene Strata

The Pleistocene strata at Bournemouth consist a few metres thickness of subangular, flint gravels. These are seen in the cliff-top exposures. They are sometimes covered with a small thickness of blown sand. The terraces are mostly of gravel terrace 10, but also terrace 9 (slightly lower) in part of the Southbourne cliffs. The gravels are the result of the melting floodwater of Spring in this periglacial region. The ice sheet was further north, probably north of the Mendip Hills. During these periglacial phases, there was no English Channel and much of the gravel was transported away to the south and to the English Channel River. Pleistocene palaeoclimatic changes were complex, and there were many alternation between cold, periglacial phases and warm temperature phases like that at present. The British has not been long at all in the modern temperate conditions, probably only a almost minute interval of time of about 10,000 years (compare to typical Jurassic sedimentation in Dorset of about 40,000 years a metre - to a geologist ten thousand years back is regarded as yesterday!).

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3.9 FORMATIONS - 9 - Holocene Sediments

[Blown Sand etc - notes to be added]

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FOSSILS

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SECTION 4 - FOSSILS OF BOURNEMOUTH

4.1 FOSSILS - 1 - Introduction

Obviously Bournemouth is not an appropriate place to search for fossils. Once a notable place, it is now disappointing. Fossil collecting is inappropriate because of the major holiday development, artificial promenade and vegetated cliffs that are closed to the public. Large number of visitors come to seafront and spend money on various amusements, food and transport. The geologist may wish to visit in winter to see the place when it is pleasantly uncrowded. However, there are good historic records of palaeobotanical finds. A few illustrations are shown here.

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4.2 FOSSILS - 2 - Marine Shells

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4.3 FOSSILS - 3 - Plant Fossils in the Bournemouth Cliffs

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An east-west cliff diagram of the coast between Boscombe Pier and Canford Cliffs, Bournemouth, Dorset, showing simple geology of the Eocene, Branksome Sand Formation and Boscombe Sand Formation, and with data on fossil plant occurrences, largely after Gardner, 1879 and 1882

Leaf beds in the Bournemouth cliffs

Above are diagram based on old work on the Bournemouth Cliffs when they were still well-exposed. They are after Gardner (1879, 1881) (and have been wholely or partially redrawn at different dates of construction of this webpage. In Victorian times the sands, soft sandstones and sandy clays were referred to as the "Bournemouth Beds", divided into Lower Freshwater (now Branksome Sand Formation) and the higher "Upper Marine Series" (now known as the Boscombe Sand Formation). It is best to use the old cliff diagrams alongside the modern one, Fig. 16 on page 55 of Bristow, Freshney and Penn (1991), Geology of the Country Around Bournemouth.

The Bournemouth cliffs are notable for superb fossil plant remains. These are not normally found now because good natural exposures are limited, the cliffs are not being eroded, and there is no easy public access to the leaf-bearing strata. The cliffs here have not just been damaged by development; they have been ruined by development and largely covered by common modern plants. Thus, to find out more about the palaeobotany, is is necessary to study the classic palaeobotanical literature on this subject. Fortunately, much has been published over the years. A few examples of Bournemouth fossil plants follow

Eocene flora - leaves

Leaf bed near Durley Chine

[One photograph above is modified from part of an old photograph reproduced in Edwards (1981) and another photograph is from Ord (1914). Both images have been tinted. ]

Fossil leaves from the Pipe Clay Series of the Poole Formation, Poole Harbour and Purbeck area, Dorset

The Beaulieu River at Ipley in flood on 10 November 2008, transporting leaves from the New Forest to the Beaulieu River Estuary, Hampshire, England

An image above shows leaves from the "Pipe Clay Series" of the Poole Formation from around Poole Harbour and in the Isle of Purbeck. These leaves are slightly older than those from the Bournemouth leaf beds, but are still from the Bracklesham Group of the Eocene. The leaves were presumably washed down the rivers by floods, as happens in the New Forest nowadays, but on a larger scale and onto a major delta.

The Middle Eocene succession in the cliffs at Bournemouth is mostly between about 42 and 50 million years old, being largely Lutetian and Auversian, but ranging up to Bartonian at Hengistbury Head. The Bournemouth to Boscombe Cliff section was by far the most interesting and important display of Eocene beds in the district of the Hampshire Basin, in the opinion of William Ord in 1914. Unfortunately the completion of the Undercliff Drive, before 1914, practically closed it to geological investigations, although sedimentological studies have been made since (Plint 1980; 1982; 1983a; 1983b; 1988). Mr Starkie Gardner wrote important papers describing the coastal exposures in 1879 and 1882 with information on the plant remains. The cliff sketch above based on Gardner's classic work shows the positions of the main leaf beds. The central photograph shows the limited development of the Bournemouth coast at the turn of the century (1899), while the right photograph shows a leaf bed near Durley Chine a little later (pre-1914). These old photographs are to set the scene of the Bournemouth cliffs as they once were. In the past there were good geological exposures like those at Hengistbury Head or Hordle Cliff at the present day. Illustrations of this webpage show something of the locations and contents of the leaf beds. Further information on leaf discoveries is given in the sections below on specific parts of the coast.

The relatively recent state of the cliffs in terms of exposures is shown by Daley and Crewdson (1987). They have provided a cliff diagram showing the small percentage of cliff area that remains uncovered with some information on the strata visible, and in the text, comments on the exposed sections.

More on the Fossil Leaves

Gardner commented that cliffs consist of yellow or whitish sands containing occasional masses of clay or loam, in which were found lignite and rarely leaves of plants. The clay usually appears in lenticular masses, but occasionally occurs in dark carbonaceous beds, sometimes a hundred metres in extent (see illustration). Pockets of impure china clay occur frequently here, but become rarer as Bournemouth Pier is approached.

The left-hand image below shows the type of preservation of the leaves in clay, in this case white pipe clay. This particular specimen found in 1882, comes from the Bagshot Beds of Alum Bay and is about 8 cm in length (modified from Kirkaldy, 1967. The other illustrations below are provided to show some of the variety of leaves that have been found in the Middle Eocene strata; some come from Bournemouth, some from Alum Bay on the Isle of Wight and some from the Corfe Castle area of Dorset. They are modified from the work of De la Harpe and Salter (1862). See Chandler's publications for modern identifications of similar fossil leaves. Apart from in the Natural History Museum in London, good specimens can be seen at the Bournemouth Natural Science Society's building. They can still be found in the region occasionally; a specimen was found a few years at Canford Heath, west of Bournemouth. Old clay pits are worth exploring and cliff sections which may contain leaves exist at Alum Bay and Studland Bay.

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Leaf in pipe clay

Eocene flora - fig leaves etc

Eocene flora - leaves and pods

These beds were examined and described by Gardner in the late 19th Century, and a number of leaves of sub-tropical plants were obtained, also many net-veined ferns [see illustrations]. The main genera represented were Acacia (thorny shrup -source of gum arabic - note that the gum residue known as succinate occurs in the Bournemouth cliffs according to Ord, 1914), Smilax, Lygodium, Myrica, Eucalyptus (the gum tree now confined to the Australian region), and Araucaria (relatives of the Monkey Puzzle and Norfolk Island Pine). There are large collections in the Natural History Museum at South Kensington (see the work of Chandler for later descriptions). The collections are of special importance because, as Ord noted by 1914, these leaves were rarely met with by that date; the lenticular masses of clay from which collections were formerly made have long since fallen from the cliff and disappeared. The clay that was exposed in 1914 does not contain the same remains, but few fossils could be obtained then from this section of the cliff. At the present time the cliffs are greatly obscured by a promenade, sea-defence works and vegetation.

Aralia leaf reconstruction

In his description of the beds between Poole Harbour and Boscombe Pier, Gardner published a diagram showing the position of the more important clay lenses, and the cliff-section above is based on later versions of this. From the west, the first important bed occurred near Canford Chine, where Lygodium and Laurel, together with Hornbeam and Willow leaves, were found. (The illustration here is of a leaf of a herb common in the region - Aralia of the gingseng "five-finger" family. The specimen is from Alum Bay.)

Proceeding from here to near Branksome Chine, Gardner recorded a dark bed of clay almost full of leaves massed together. Ord in 1914 was unable during the previous two years to trace any of these beds. About one hundred metres east of Branksome Chine, though, he found masses of friable yellow sandstone containing numbers of beautiful leaf impressions, amongst which were oak and willow. They were so well preserved that several circular holes which had been eaten out by insects could clearly be seen. These specimens were on display in the Museum of the Bournemouth Natural Science Society. For half a mile from this point no leaves have usually been found, but in a mass of carbonaceous sand near the beach level trunks of several coniferous trees was exposed, the wood being extensively bored by Teredo.

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4.4 FOSSILS - 4 - Plant Fossils - Palaeoclimatic Implications of Bournemouth Eocene Flora

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The hot, wet, forest and delta-swamp palaeoenvironments in which the Bournemouth leaf beds of the Eocene originated (reconstructions, based partly on Webster Smith ,1931),

A modern tropical swamp environment with the stemless palm Nipa, the fruits of which occur in the deposits of the Eocene, Poole Delta at Bournemouth, Dorset and elsewhere in the region

The latitude of Bournemouth is now almost 51 degrees N and the modern vegetation is of temperate type. The Bournemouth leaf beds, of Middle Eocene age and deposited between 50 and 42 my ago, originated in a palaeolatitude which was at about 40 or perhaps more accurately 42 degrees N ( Smith and Briden, 1977 ) and they are notable for containing both temperate and tropical types of plants. This is a latitude like that of central Spain at the present day, not that of equatorial rain forests, and the presence of tropical plants is an anomaly. Plants of such a warm origin are particularly abundant in the Lower Eocene, London Clay (Daley, 1972) . The Bournemouth leaf beds of the Middle Eocene originated slightly later but contain some tropical plant remains, such as Nipa (see the stemless palm in the reconstruction of Webster Smith, 1931, above), like those in the London Clay. Reid and Chandler (1933) concluded that the London Clay flora compared most suitably with the present day vegetation of the Indo-Malayan region. This, they suggested, indicated a Tropical Rain Forest climate during the Early Eocene times in southern Britain, with a mean annual temperature of 21%° C (although nearer to 25-26%° C according to Richards, in Chandler, 1964 ). Doubt, however, arose as to whether truely tropical conditions could have existed at such a high palaeolatitude (Daley, 1972) . A further problem is the occurrence in the London Clay of 11.5 %% of purely extra-tropical genera and it should be noted that other genera are present which live in both tropical and extratropical conditions at the present day. Thus there was a mixture of climatic types of vegetation, both during deposition of the London Clay and during depostion of the Bournemouth leaf beds.

The comments of Daley (1972) , below, refer specifically to the London Clay of Early Eocene age. The Bournemouth leaf beds of Middle Eocene age present much the same problems and his conclusions are relevant to the environment around Bournemouth during middle Eocene times:

"It is suggested that the mixture of tropical and extra-tropical plants may have resulted from a type of climate not represented at the present day. The absence of frost allowed tropical plants to spread into higher latitudes, where they would, during cooler geological periods, have been vulnerable to low winter temperatures. Higher rainfall throughout the world during the Eocene also facilitated the poleward spread of tropical plants, since at the present day precipitation is the main factor limiting their poleward spread. Tropical plants would have become established in low-lying damp areas near rivers and lakes where adaphic moisture supplemented rainfall and where humidity was high. Under such conditions of abundant moisture supply, temperatures need not have been truely tropical. Further away from the rivers and lakes, on slightly higher land, temperate plants could have grown under somewhat less humid conditions."

The Bournemouth Middle Eocene strata were mostly deposited from about 50 to 42my, a little after the London Clay with its very tropical floral aspect. Nevertheless warm "greenhouse" conditions would have existed at this time according to current theories of content of carbon dioxide in the atmosphere. Relevant research by Dr Paul Pearson and Professor Martin Palmer was reported in the journal Nature. They used a new technique to establish CO 2 levels in the ancient atmosphere, analysing the shells of planktonic organisms that once lived near the surface of the ocean. This enabled them to establish past seawater acidity, which in turn was dictated by the amount of atmospheric CO 2 . The researchers estimate that between about 60 and 52 million years ago, CO 2 concentrations reached more than 2,000 ppm. But from about 55 to 40 million years ago, there was "an erratic decline", which may have been caused by a reduction in CO 2 emissions from ocean ridges and volcanoes, and by increased carbon burial. Thus the Eocene had a very warm, ice-free world, particularly in the early part when the London Clay was deposited but the temperature had not fallen much when the Bournemouth leaf beds were deposited. The "Hampshire Crocodile", actually an alligator named as Diplocynodon hantoniensis, flourished at the end of the Eocene and its bones are found at Hordle Cliff. The temperature must have been still moderately warm at that time for the famous Hampshire reptile to lived, but cooling was just beginning and the first winter frosts in this area may have appeared in the Oligocene.

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5 SEDIMENTOLOGY

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5.1 SEDIMENTOLOGY 1 - Introduction

The Eocene sediments of the Bournemouth cliffs are clastic. They are clays and sands, varying from freshwater or deltaic to near normal marine. The Boscombe Sands show less evidence of marine conditions than does the Branksome Sand Formation.

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5.2 SEDIMENTOLOGY - 2 - Clay Mineral Distribution [correct 24 May]

The clays in the Eocene strata of the Bournemouth cliffs have been investigated in only a few cases. In general illite and kaolinite are probably the dominant clays. The exandible clay, smectite, is probably rare or absent. It is normally found in more marine facies, particularly further east (Whitecliff Bay, Isle of Wight etc).

Clay mineral distributions in the Hampshire Basin, based on the work of Gilkes (1968), with some further palaeoenvironmental interpretation

For the general distribution of clay minerals in Tertiary strata, both onshore and offshore in the British Isles see (Huggett and Knox, 2006) . In simple terms the problem is one of the distribution of illite (the common, mica-like clay mineral), kaolinite (the white pottery-clay mineral of Devon, smectite (the greasy and expandible clay, much finer grained than the others) and mixed-layer clays (usually a combination of illite and smectite). The green mineral chlorite can also be present.

In the Bournemouth area there are white pipe clays present, especially around Poole Harbour. These are rich in illite and kaolinite and not the expandible clays like smectite and mixed layer. They cause less stability problems than does the slippery, expandible smectite. More marine clays with smectite in addition to other clay minerals are found further east, at Barton and the Isle of Wight. They are typically marine clays like the Barton Clay. The consequence of this distribution is that the cliffs of Bournemouth should be less liable to landslide than the cliffs further east with more expandible clays (ie. water-absorbing and greasy clays like smectite). The Bournemouth cliffs are therefore not comparable with the Barton Clay cliffs at Barton.

In general, this situation has long been known. However, it is shown clearly by Huggett and Knox, (2006) who show the clay mineralogy of the Bracklesham Group and the Barton Clay Formation at Whitecliff Bay, where these two units have a high smectite content, and in contrast the clay mineralogy of the so-called Bracklesham Group of the Bournemouth-Poole area. The Poole, Branksome and Boscombe Formations in the Bournemouth Cliffs and Poole area are smectite-poor and illite-kaolinite rich. (Compare the figs. 16 and fig. 21 of Huggett and Knox, (2006). The clay facies change is associated with non-marine sediments entering the basin through the Poole Delta. From a civil engineering point of view, there is less tendency for the cliff of Bournemouth to landslip, although this does happen occasionally (partly because the cliff angle is fixed by an immovable Overcliff and an immovable Undercliff Drive, and partly because fallen debris is not left in place so as to reduce the slope, but instead is removed from the base of the cliffs).

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5.3 SEDIMENTOLOGY - 3 - Sedimentary Structures, General [correct 24 May]

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5.4 SEDIMENTOLOGY - 4 - Liquifaction

The "Earthquake Bed" which is near the top of the Branksome Sand Formation shows contortions, water escape structures. It has probably been subject to liquifaction when the area was struck by a major earthquake. The occurrence of such an event is not all surprising because this was almost exactly the time when the southern parts of the Isle of Purbeck (Creechbarrow) and the southern parts of the Isle of Wight were uplifted. The bed coincides in time almost exactly with the very start of the Tertiary (Alpine) tectonic movements. This was initial folding at a very moderate angle, and low before the Chalk aquired a vertical attitude at the Needles, Isle of Wight, and Ballard Point, Isle of Purbeck. It was just the first phase.

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6A BOURNEMOUTH CLIFF GEOMORPHOLOGY

6a1 Cliff History (part) - State of Cliffs in 1912.

The Chines and Cliffs of Bournemouth [- by C. Carus-Wilson in February, 1920]
[Professor Charles Ashley Carus-Wilson, Lecturer and Engineer]
Geological Magazine, vol. 57, issue 4, April 1920, page 120 only.

Sir - I believe that Mr Bury [Henry Bury, geomorphologist, member of Bournemouth Natural Science Society] is correct in assuming that I am responsible for the statement regarding the general increase in the steepness of the Bournemouth Cliffs. It was made in a lecture on "The Bournemouth Cliffs" delivered at Bournemouth in the spring of 1912. The matter was discussed at the Geological Society after the reading of Mr Bury's paper on January 27, 1916.
As I have not visited Bournemouth since 1912 I am unable to refer to the appearance of the cliffs at the present time [1920], but in 1912 the alteration of the general angle of face-slope was unmistakable, and, in fact, was noticed by several local observers, and subsequently corroborated by the comparison of numerous photographs taken between 1887, when my systematic observations began, and 1912.
Since the Undercliff Drive was constructed there has been a general lowering of the beach westward, and hence a more rapid removal of cliff talus from the base through marine erosion and transport, while at the same time, there has been no proportionate increase in the rate of atmospheric erosion upon the cliff-face. Hence the general angle of slope is no longer approximately 35 degrees, as was formerly the case. I predicted these changes when giving evidence at the Local Government Board Enquiry held at Bournemouth in 1906, and many years before than in the local papers.
It has always seemed to me that an important factor in determining the width and depth of a chine in the making is the bed of clay, or ferruginous sandstone, so frequently present at varying depths below the surface. A stream cutting its way through the softer sandrock ceases to erode its bed with the same rapidity when reaching a stratum of clay or sandstone below, while the widening of the chine by the atmostpheric agencies continues to progress at the same rate.

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SECTION 6B - BEACHES AND BEACH PROCESSES

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6B.1.

BEACHES - Introduction
Bournemouth is, of course, notable for sandy beaches, within a bay that does not have strong tidal currents. It is a relatively safe place to swim. The benefit of the sandy beaches was recognised long ago. They were at the foot of naturally eroding cliffs of Eocene sands and sandstone, with some clay. There was a plentiful supply of sand originally. Of course, before any esplanade or undercliff drive was constructed the natural beach was reasonably wide, being uncovered with stone or tarmac. There is no impression from photographs that the beaches were very wide, and they never naturally reached the extraordinary and unnatural width of the replenished beaches of 2016 (and of previous years to a lesser extent). Dawlish is another south coast town with sandy beaches. There they have been eroded away without replenishment from the cliffs and the town cannot afford the expensive artificial replenishment that has taken place at Bournemouth.

The replenishment system works at Bournemouth, where presumably there is adequate funding for such an expensive procedure. However, the sand does not all remain in place. Some is not lost, but much (that is sand east of Bournemouth Pier) is transported eastward by longshore drift. A very large amount of this artificial sand from Bournemouth is now at Hengistbury Head. I have lived near there back in the 1950s and I know that there was a problem then about loss of beach sand and consequent erosion. Now, years later and in another century, it is astonishing to see so much sand that has come from Bournemouth. People once concerned about the erosion of Hengistbury Head can now relax, knowing that the headland is the natural dumping ground for sand derived from Bournemouth. Mudeford Spit is the direct product of sand, originally natural and from the Bournemouth cliff.

.[ Beaches continued]

Present sand sediment transport on the beaches of Poole Bay, Bournemouth, Dorset, and possible implications for the Sandbanks Peninsula in the future

The topic of supply, movement and loss of beach sand on Bournemouth beaches has been well studied by SCOPAC. A very simplified diagram is provided above, but it recommended that the full SCOPAC MAP be studied. It contains quantitative data, not given here. For technical information on this topic go to:

SCOPAC - Sediment Transport. SCOPAC - Standing Conference on Problems Associated with the Coastline. There are many sections in this important publication. There is a an index map at: Sediment Transport Study - map showing areas.

More specifically for Poole Bay, Bournemouth and Sandbanks visit the map with detailed sediment transport information at:

Poole Harbour Entrance to Hengistbury Head">

In general terms the sandy beaches of Bournemouth and Poole Bay have derived their sand from the erosion of the Eocene strata in the cliffs. Sandbanks has in particular resulted in part from a good sand supply from the Branksome Sands, forming the cliffs of the western part of Poole Bay, particularly from Durley Chine westward. The Branksome Sand Formation is 70m thick; it takes its name from Branksome Chine [SZ 069090] and is of Bracklesham age Bristow et al. (1991).

The Boscombe Sands, 20 to 27m thick, are present in the Bournemouth Cliffs from Durly Chine eastward, past Bournemouth Pier and on to Southbourne. They reappear at Hengistbury Head (Bristow et al., 1991). In the past, before the construction of the promenade from about 1914 onward both the Branksome Sand Formation and the Boscombe Sand Formation contributed much sand to the Bournemouth Beaches, and made them a favourite bathing area. In addition there was some supply of both subangular flint pebbles and some sand from the Pleistocene gravel terraces, just a few metres thick at the tops of the cliffs.

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6B.2.

BEACHES - Sand Replenishment

Beach replenishment is a regular feature at Bournemouth, in fact it seems to happen more there and on a larger scale than at anywhere I know. There is, of course, a good reason for this. Bournemouth, back in the past was notable for lovely sandy beaches and lovely yellow,sandy cliffs. The cliffs supplied the beaches. Then in 1914 the cliff were "locked-up" by the building of a promenade along most of the Bournemouth Coast. The cliff-top was also effectively fixed by the construction of an Overcliff Drive and other roads. Therefore the supply of sand ceased. The beaches began to diminish as there was always a loss to the east by longshore drift. The storm waves come from the southwest. The eastern coast of the Isle of Purbeck (Durlston Head and Ballard Down, Swanage) provide some protection to central Bournemouth and much to Sandbanks. Further west at Southbourne the southwesterly storm waves can attack without much hindrance.

Now with natural sand supply from Bournemouth cliffs cut off, erosion and loss of beach sand took place. The problem was greater in the down-drift direction. That is towards Southbourne and Hengistbury Head. There has been major erosion at both places (details are shown in relevant sections and the Hengistbury Head webpage).

The economics of the Bournemouth tourist industry meant that beaches had to be relaced if they were lost. Artificial beach replenishment at regular intervals has become a major aspect of the Bournemouth coast. Without it there would be erosion similar to that at Dawlish in Devon. While Bournemouth is obviously wealthy they cannot afford beach replenishment at Dawlish and so the sea has removed the beach at places and from time to time the sea destroys the sea wall and breaks through the major railway line. See the Dawlish webpage. Such first stages of coastal reatreat are not allowed at the wealthy coastal town of Bournemouth.

The Bournemouth beach replenishment is on a very large scale and there is consequently a major loss of sand in the easterly down-drift direction. Thus Southbourne is no longer threatened and neither is Hengistbury Head. Both are supplied by longshore drift with more than adequate sand coming from Bournemouth. Because there is obviously no cost problem, Bournemouth now has bigger beaches than it ever had, even if they are artificial. As long as there is plenty of money Bournemouth will survive with beaches, promenade and cliffs almost intact. If, for any strange reason the funding ceased, then normal erosion will recomence; the promenade will be undercut and the cliff will start eroding (although not necessarily fast). Southbourne and Hengistbury Head will probably suffer most. [This is just a description of the situation as seen by the writer, who has no views for or against beach replenishment, but of course as a geologist likes to see exposed cliffs.] No major change is really expected until a great storm (e.g. 1824) or a tsunami returns and destroys the beaches and attacks the cliff once again. In general rising sea-level and increased storm activity may put pressure on sea defences and beach replenishment in the future, but that does not seem to be an immediate problem.

For more detailed information on beach replenishment, see, in particular, the Mackley webpage:
Mackley 2016 - Good Progress on Bournemouth Beach. [Also in Reference List below under Mackley]. Beach replenishment is not described in detail in this webpage; it is just a supplementary matter in relation to the geology.


Short extract "Mackley is making good progress on the first phase of a long-term project to provide enhanced protection to Bournemouth beach. The current works are part of the Bournemouth Beach Management Scheme, a 17-year programme of work planned from 2015 to 2032. The scheme will eventually see all of the existing 53 groynes replaced and an additional three new groynes constructed, along with beach replenishment every five years.

[Discussion Points. This is understandable for an important holiday resort. However a substantial proportion of the beach replenishment material travels eastward by longshore drift. It is already substantially affecting the Hengistbury Head area (for better or worse according to your point of view). It will travel to Mudeford Spit, and ultimately a proportion will go on to Barton-on-Sea. It is not clear just what will happen from there onwards. Will it pass the limestone rock armour at Barton? Could it lead to a new sandspit development just east of Barton. That area is already problematic, with loss of shingle to Hurst Spit (the main part of which has been destroyed more than one). The sand regularly lost from Bournemouth might be a problem or it might be advantageous elsewhere; the matter is not simply because there are complications of varying erosion rates to the east and the matter of rising sea-level. In addition the big event, the one-in-250 year storm (like 1814) has no happened again yet. There has been no repeat yet of the 1775 tsunami - there are many unknowns.]

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6B.3.

BEACHES - Loss of Beach Sand

If there was no loss of beach sand from Bournemouth there would be no need for beach replenishment, although it is true that the authorities may wish the beach to be larger. The direction of travel of beach sand can be seen by looking at groynes. The sand accumulates on the updrift side, and is loss on the downdrift side. So examine the extent of asymmetry. [end of 6b section]

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7. LOCATION

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7.0 LOCATION - 0 - Sandbanks

For Sandbanks - please go to the specific Sandbanks Webpage:
Sandbanks Peninsula webpage.

A helicopter view of the central part of the Sandbanks beach, Dorset, where there is some sand loss by longshore drift towards the northeast, photograph 6th July 2013

The cliffs of Bournemouth, largely overgrown can be seen in the top right-hand corner of this helicopter photograph (from the Sandbanks Webpage).

Old Harry Rocks seen across Hook Sand from Sandbanks, Dorset during a southwesterly gale

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7.1 LOCATION - 1 - Canford Cliffs

Limited cliff exposures of the Branksome Sand Formation at Canford Cliffs, west of Bournemouth, Dorset, helicopter view, 2013

The Eocene, Branksome Sand Formation is 70 metres thick and named after Branksome Chine [SZ 069 090] and crops out in a 5 km wide arc from Ferndown in the north, through Parley, the northern part of Bournemouth and the Branksome area of Poole. It is also well exposed in the yellow sandy cliff in the northeastern corner of Brownsea Island in Poole Harbour Bristow, Freshney and Penn (1991).

Gardner (1882) reported in relation to Sugar Loaf or Canford Cliff Chine (on page 7) as follows:

"Under the leaf-bed just described five reefs of pyrite are visible at low water, running south-east with a WSW dip [this is almost opposite to the regional dip, but local depositional dips are common in the Branksome Sand Formation]. These are succeeded by dark clay dipping E. [expected direction], at about 1 in 50, in which I observed a palm trunk in situ and numerous spines, and a bed of hard lignite, from 6 inches to a foot thick, underlain by brown clay with roots [a palaeosol] and covered by pyrites. Rocks of pyrites again occur opposite Watering Chine [Branksome Glen Chine, west of Branksome Chine], although they are never quite uncovered by the sea; and by means of a diver I was able to trace them two miles seaward towards Alum Bay."[i.e. almost to south of Bournemouth Pier, and therefore passing south of Alum Chine. Note the intentional reference to Alum Bay; pyrite was collected there from strata of similar age for alum production].

Now at Canford Cliff Chine (Sugar Loaf Chine) the top of the Parkstone Clay Member descends with easterly dip under the beach. This then is exactly the same horizon as the pyrite bed on Brownsea Island, only 4km. to the southwest, notable for the historic copperas workings. Although the local dip is anomalous, the regional dip is consistent. Thus it is quite clear that Gardner was following the offshore outcrop of the top of the Parkstone Clay Member. The outcrops at Canford Cliff Chine and on the south side of Brownsea Island are of the exactly the same bed! Alum Chine, is stratigraphically well above the Parkstone Clay pyrite bed, but pyrite could occur there in the Branksome Sand Formation (or the chine might be wrongly named and the real "Alum Chine" is Canford Cliff Chine).

It is worth noting that in Overton's map of 1600 there is indicated "Allom Chine Copperas House" and "Bascombe Copperas House" (ie. at Boscombe) (Riddle (1934) so copperas working was not confined to the Parkstone Clay outcrop or shore exposures. Presumably pyrite could be obtained from the Boscombe Sand Formation, as is supported by the presence of the acid springs.

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Poole Head and the Canford Cliffs area, Bournemouth, Dorset, a helicopter view in 2013

Promenade and sea-wall at Canford Cliffs, west of Branksome Chine, Dorset

Branksome Sand at Canford Cliffs, west of Branksome Chine, Dorset

Planar Cross-stratification in the Branksome Sands, Canford Cliffs, Dorset

The Branksome Sand Formation of the Bracklesham Group (Bristow, Freshney and Penn, 1991) is shown here in the isolated but quite good exposure at Canford Cliffs, west of Branksome Chine. These strata were once known as the Bournemouth Freshwater Beds of the Middle Bagshot Sands. The Branksome Sand is 70m in thickness and named after Branksome Chine (map reference SZ 069090) (Bristow, Freshney and Penn, 1991). The Branksome Sand occupies most of the cliff at Canford Cliffs and thence descends eastward in the cliff with the gentle easterly dip. The uppermost part (G), or the Bournemouth Marine Beds contain some marine molluscan remains. These strata extend as far as Southbourne at the foot of the cliff. The lower part, the Bournemouth Freshwater Beds (cycles A to F discussed below) contain plant remains but no marine macrofossils (but see the memoir re dinoflagellates). They have not been recognised far to the east of Bournemouth Pier. The age of the Branksome Sands may be disputed but is probably somewhere near Auversian or Upper Lutetian (equivalent to an upper part of the marine Bracklesham Group further east - perhaps the Selsey Formation).

The Branksome Sand Formation consists of seven fining-upward cycles, of which seven were lettered A to G in ascending order by Plint (1983b) . The right photograph above shows some of Plint's cycles, although the details are not clear without a close study of the section. An idealised cycle (and note well that is idealised and in practice not all parts may occur) commences with a very coarse-grained sand, often containing clay clasts, resting on an erosion surface. This is succeeded by coarse- to medium-grained sand showing large-scale, planar cross stratification (look at the photographs. You can clearly see planar cross-stratification. What was the general current direction here?). This passes up into medium-grained sand in which the cross-bedding is on only a decimetre scale. The cycle is capped by interbedded fine-grained sand and silty clay (Bristow, Freshney and Penn, 1991). Cross-bedding directions are surprisingly variable and it is a pity that they do not make a simple pattern.

In terms of composition the sands consist mainly of quartz, with some flint grains which are more noticeable in the coarser-grained sands according to (Bristow, Freshney and Penn, 1991). Remember that the palaeoclimate and palaeoenvironment, although theoretically warm-temperate, was in some respects almost tropical in type. With this in mind you may not be surprised to observe that this particular quartz-arenite is mineralogically mature. However, this is probably not the complete explanation. Think, for example, about the Namurian "Millstone Grit" of the north of England. That came from an equatorial environment yet, containing much feldspar, is not as mature as the Branksome Sand. Apart from the palaeoclimate there was likely to be another factor with regard to the Eocene sand, and this was the extent of reworking. Jurassic and Cretaceous sand were probably exposed to the west in Eocene times and the Trias was an obvious source of quite mature sand. We will leave the maturity topic here but it can pursued, if required, by consulting the heavy mineral literature (is there garnet - a common New Red indicator?).

To see a very good section of the Branksome Sand elsewhere and an indication of just how the Bournemouth appeared before the construction of sea defences go to:

Brownsea Island, Poole Harbour webpage.

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7.2 LOCATION - 2 - Branksome Chine
(Note that back in the past there have been some terminological changes as to just which was Branksome Chine. It may not be the present, well-known chine with a major road and a car park. )

Silicified tree remains from the basal Purbeck Formation found amongst rock armour from Portland and Purbeck strata at Branksome Chine, Poole, Dorset, 2009

Incidently some of the rock armour here may have come from the quarries of the Isle of Portland. Purbeck fossil trees in silicified condition are common there. This portion of a tree trunk is probably from Portland.

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7.2a LOCATION - 2a - Branksome Dene Chine

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Geological cliff section from the Zigzag, west of Bournemouth Pier to Branksome Dene Chine, Bournemouth, Dorset

Two units of the Eocene Branksome Sands at Branksome Dene Chine, west of Bournemouth, Dorset

Laminated, lignitic clay and sand in a channel plug at Branksome Dene Chine, Bournemouth, Dorset

The east side of Branksome Dene Chine provides a reasonable section of part of the Branksome Sands. In the lower part of the cliff there is a grey laminated bed, a type of leaf bed, developed at the margin of a channel. It consists of argillaceous silty sand and silty, sandy clay. There are alternating laminae of sand and clay. This is fluviatile unit C of Plint (1988).

A coarse sandstone or granule bed with small pebbles in the Branksome Sand Formation at Branksome Dene Chine, Bournemouth, Dorset

Higher in the cliff is a fluviatile sand and sandstone on yellow and brownish colour with very little clay. A bed near the base is very coarse with particles of granule size or larger. These are mostly of vein quartz and are subangular. There are some darker clasts which may be of tourmalinised slate or tourmaline (the typical material of the Eocene fluvial deposits in the Dorset area is derived from southwest England). The sequence in the upper part of the cliff belongs to fluviatile unit D of Plint (1988). It is a fining-upwards sequence. In the top of the cliff is Pleistocene gravel.

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7.3 LOCATION - 3 - Alum Chine
(with former pyrite industry at Alum Chine and Boscombe Chine)

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Norden's map of 1595 showing the location of copperas houses at Alum Chine and Boscombe (Bascoombe), Bournemouth, Dorset, slightly modified for clarity

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Please go to Brownsea Island - Copperas, Melanterite for more information on production of copperas in this region in historic times.

The Bournemouth beaches, including those of Alum Chine have been extensively renourished with dredged sand. This in addition to sea defences and promenade means that there is little indication there now as to what was the original appearance of the beach.

Ord in 1914 reported that near Alum Chine hard masses of ferruginous sandstone could be seen at low water on the beach, extending for some distance eastward, being one of the few examples of any hard stone occurring in this section of the beds. Although the name "Alum Chine" suggests that pyrite was found there, a reliable geological record places occurrences further west, at the top of the Parkstone Clay Member of the Poole Formation. It is not impossible, though, that significant quantities of pyrite was present near the existing Alum Chine. Gardner (1882) recorded pyrite shore occurrences east of Sugar Loaf Chine and at at Watering Chine (or Branksome Glen Chine). Not far away, offshore at Poole Rocks there is a major deveopment of pyrite pipes.

There is an important leaf bed, the Willow Bed, in the Branksome Sand Formation, to the east of Canford Cliff Chine (also known as Sugar Loaf Chine), and 100 yards east of Branksome Watch Tower. The leaf bed was referred to as a stratigraphical marker. Stratigraphically beneath it there is a major occurrence of pyrite in the strata, almost certainly in the underlying Parkstone Clay Member of the Poole Formation.

Sea water was not far away during deposition of the Eocene strata of the Poole Delta and the Bracklesham open sea was to the east. Thus sulphate was probably readily available and able to be in contact with decomposing plant debris. Such a combination was ideal for the formation of pyrite. It is widespread in the Poole Formation, particularly the Parkstone Clay The seaward part of the Eocene Poole Delta was coincidentally actually in the general region of the present entrance to Poole Harbour (Branksome, Studland, Parkstone, Poole Rocks etc). Here the pyrite development was at its maximum.

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7.4 LOCATION - 4 - Durley Chine

At Durley Chine there have been occasionally found small masses of a hard dark grit known locally as 'Durley Rock.' It is composed of pyritised vegetable debris with carbonaceous sand. In Durley Chine masses of quartz grit cemented by iron are seen a little distance up the Chine. They form a continuous bed which extends, as far as can be traced, for some hundred yards inland. This gives the strike of the beds as roughly north-northeast (Ord, 1914).

By far the most interesting cliff-section palaeontologically is that from Durley Chine to the Pier. Here Gardner obtained many net-veined ferns, especially Gleichenia, also Aroids and a Eucalyptus. A great rarity found farther west was a fossil feather . Palm fronds have frequently been met with, and a magnificent specimen on a slab nearly three feet square is in the Natural History Museum, at South Kensington, London (Ord, 1914).

The conditions under which these strata were laid down are interesting. The deposits are of fluviatile or deltaic origin, and must have been formed in the bed of a great river coming from the west. The quartz sand, which forms the bulk of the cliffs and is of very pure, and together with the white china clay, has been considered to have originated in a granite country (Ord, 1914). Gardner thought that the Bovey Tracey Lignite Beds (now regarded as Oligocene) and the ball clays of Devon were laid down contemporaneously by the same river. He considered that the granites of Dartmoor, Cornwall, and probably an extent of land which has long since been eroded away or submerged in the Atlantic, supplied by its decomposition the quartz sand grains and the china clays. Somewhat similar clays are now worked extensively in the granite regions of Devon and Cornwall, but these are dominantly kaolinite clays, whereas the ballclays and pipeclays of the Bournemouth area are usually kaolinite and illite (and more plastic).

According to Ord (1914) the delicacy of the beautifully preserved leaves in the lenticular clay beds shows that these must have been deposited under tranquil conditions in shallow ponds and lagoons by the sides of the main stream. Through these a gentle stream of clay-hearing water continuously flowed, while the leaves were borne down by the stream or blown in from trees in the vicinity. Now and again the river would overflow its banks and temporarily swamp these side waters, covering them up with layers of sand and coarser material. From the thickness of the beds it is evident that the land was slowly sinking, so that the river channel probably remained at the same level for long periods. Together with the leaves, trunks of trees and water-logged masses of wood floated about; these were attacked by the Teredo shipworm and rapidly bored through and through. This shows that there were some marine incursions into the swamps of the delta. Occasionally there are sand casts of these borings imbedded in a matrix of sand or mud, the woody material having entirely perished, leaving only a dark discoloration where it formerly existed.

[Durley Chine continued]

At Durley Chine there have been occasionally found small masses of a hard dark grit known locally as 'Durley Rock.' It is composed of pyritised vegetable debris with carbonaceous sand. In Durley Chine masses of quartz grit cemented by iron are seen a little distance up the Chine. They form a continuous bed which extends, as far as can be traced, for some hundred yards inland. This gives the strike of the beds as roughly north-northeast (Ord, 1914).

By far the most interesting cliff-section palaeontologically is that from Durley Chine to the Pier. Here Gardner obtained many net-veined ferns, especially Gleichenia, also Aroids and a Eucalyptus. A great rarity found farther west was a fossil feather . Palm fronds have frequently been met with, and a magnificent specimen on a slab nearly three feet square is in the Natural History Museum, at South Kensington, London (Ord, 1914).

The conditions under which these strata were laid down are interesting. The deposits are of fluviatile or deltaic origin, and must have been formed in the bed of a great river coming from the west. The quartz sand, which forms the bulk of the cliffs and is of very pure, and together with the white china clay, has been considered to have originated in a granite country (Ord, 1914). Gardner thought that the Bovey Tracey Lignite Beds (now regarded as Oligocene) and the ball clays of Devon were laid down contemporaneously by the same river. He considered that the granites of Dartmoor, Cornwall, and probably an extent of land which has long since been eroded away or submerged in the Atlantic, supplied by its decomposition the quartz sand grains and the china clays. Somewhat similar clays are now worked extensively in the granite regions of Devon and Cornwall, but these are dominantly kaolinite clays, whereas the ballclays and pipeclays of the Bournemouth area are usually kaolinite and illite (and more plastic).

According to Ord (1914) the delicacy of the beautifully preserved leaves in the lenticular clay beds shows that these must have been deposited under tranquil conditions in shallow ponds and lagoons by the sides of the main stream. Through these a gentle stream of clay-hearing water continuously flowed, while the leaves were borne down by the stream or blown in from trees in the vicinity. Now and again the river would overflow its banks and temporarily swamp these side waters, covering them up with layers of sand and coarser material. From the thickness of the beds it is evident that the land was slowly sinking, so that the river channel probably remained at the same level for long periods. Together with the leaves, trunks of trees and water-logged masses of wood floated about; these were attacked by the Teredo shipworm and rapidly bored through and through. This shows that there were some marine incursions into the swamps of the delta. Occasionally there are sand casts of these borings imbedded in a matrix of sand or mud, the woody material having entirely perished, leaving only a dark discoloration where it formerly existed.

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7.5 LOCATION - West Cliff and Lift

Some old photographs of the cliffs here, modified from postcard views follow:

Excellent cliff exposures in the Boscombe Sand Formation over the Branksome Sand Formation in the cliffs to the west of Bournemouth Pier, Dorset at about the end of the 19th century

The beach just west of Bournemouth Pier, just before the long promenade was built in 1904, Bournemouth, Dorset, at low tide

A vertical cliff, about 100 feet, high, and near the modern Zigzag Path to the west of Bournemouth Pier, Dorset as seen in about 1900

The West Cliffs of Bournemouth, Dorset, in 1920, when they were still partly in natural condition, in spite of development at Chines

Now, unfortunately, the cliffs immediately to the west of Bournemouth Pier are overgrown and not accessible to the public. There is an esplanade and buildings and beach huts at the base. It is a very urban place now and there is even a large conference hall on the cliff top. The sloping remains of the cliff is badly overgrown with miscellaneous vegetation. However, back in the past, at the end of the 19th century and the very beginning of the 20th century, and as shown in photographs above, this was an important geological site. It was an almost natural piece of coast with excellent cliff exposures. It was a special place for Eocene fossil plants. The pier was conspicuous then as it is now, but it served a useful purpose for access to paddle steamer trips to other parts of the coast.

Notice that generally the old photographs shown no groynes on the beach (there is a possible indication of one near Alum or Branksome chine). The beach width was quite good, roughly about 100 ft or 30 metres at high tide. The beach, obviously was supplied by sand from natural cliff falls and some fans of debris can be seen in some of the photographs. The cliff was, of course, receding, although at only a moderate rate. Bournemouth was then a small, quiet coastal town, a natural place no more developed than, perhaps, Budleigh Salterton in Devon, at the present time. Inevitably, of course, there have to be large coastal towns somewhere and once heavily built up there has to be continual expenditure to stop, at least for the present, the natural retreat of the coast. This has not be difficult to do at Bournemouth because there is some natural protection from southwesterly storm waves by the projecting Isle of Purbeck (Harry Rocks, Durlston Head etc). At Southbourne, less protected from major storm waves, sea defence work has lasted temporarily, but of course the place now regularly receives the lost, beach replenishment sand drifting eastward from Bournemouth. That has been the situation after the 1950s, when Bournemouth had a narrow beach and significant erosion was still taking place at Southbourne. Nowadays, there is the funding and the methods to retain an historic, rather than the natural, position of the coast-line.

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7.6 LOCATION - - Bournemouth Pier

A general helicopter view of Bournemouth Pier and adjacent coast, showing overgrown cliffs of Eocene sand and clay, 6th July 2013

A view of Bournemouth Pier, looking southwest from a hotel balcony, Bournemouth, Dorset, 25th April 2007

A general view of Bournemouth Pier from the promenade on the west side, as seen in the late afternoon on Saturday, 8th March 2014

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Bournemouth Pier and vicinity, Dorset, in 1868, at that time a quiet coastal locality with natural Eocene cliffs, no promenades and no crowds

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An old photograph of Bournemouth Pier, the beach and the cliffs from a viewpoint on West Cliff, Bournemouth, Dorset, from about 1905 and before the promenade was constructed

Bournemouth Pier Approach in 1899

An old photograph of Bournemouth Pier, the beach and the cliffs from a viewpoint on the East Cliff, Bournemouth, Dorset, near the present Russell-Cotes Museum, taken round about 1905 and before the promenade was constructed

A major storm, with wave reflection, hits the new promenade, just east of Bournemouth Pier, Dorset, in about 1904

Bournemouth Pier, Dorset, passengers disembarking from the Lorna Doone paddle steamer in 1931

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At Bournemouth Pier, incidently, traces of a much younger forest which could formerly be seen. The submerged forest, like many in the region (compare with Hayling Island submerged forest) was probably Neolithic in age Ord (1914). It was uncovered at low tides, stumps of coniferous trees being exposed abundantly, in their original sites.

Some photographs above show that before the promenade was built in about 1914, there was a substantial beach, probably wider than the beach in the 1950s before beach replenishment processes commenced. The cliffs were sloping at an angle close to the theoretical figure for dry sand of 34 degrees. There had been minor cliff-falls and fans of sand and sandstone debris. In general the cliff was similar to modern cliffs, without a sea wall, at Hengistbury Head. It is obvious though that the cliffs were supplying sand to the beach in significant quantity. There is no indication in the old photographs of rotational cliff falls in this central Bournemouth area. A photographs exists of a limited rotational cliff landslide at Southbourne in about the early 1950s.They are not normal for Poole Bay but occur abundantly in the clay cliffs of Barton-on-Sea in Christchurch Bay.

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7.7 LOCATION - 7 - East Cliff: Bournemouth Pier to Boscombe Pier

Introduction

Geology of the East Cliff, Bournemouth, Dorset - diagram

A channel fill in the Branksome Sand Formation, between Bournemouth and Boscombe Piers, Dorset, 4th July, 2008

East Cliff, Bournemouth, Dorset, view from pier

Branksome Sand just west of Boscombe Pier, June, 2002

A view of an exposure in the lower part of the cliffs behind the wall, just west of Boscombe Pier, shows some conspicuously laminated beds of clayey silt and very fine-grained sand, the Branksome Sand (Bristow, Freshney and Penn, 1991, p. 62). There are some fine, brown clay layers and much fine-grained lignitic debris. This dark lignitic material marks out partings. Notice the wedge-bedding, a form of cross-bedding on a large scale. The uppermost part of these laminated beds is brown and ferruginous. Above Plint's T4 transgression surface (a major break in sedimentation according to Plint) comes the creamy-white Boscombe Sands which are medium-grained and lack the conspicuous lamination. The laminated sediments, the upper part of the Branksome Sand, belong to the Bournemouth Marine Beds on an older classification, and near here impressions of oysters (with bryozoa) have been found (Ord, 1914).

East Cliff near the Lift, pre-1914

This old view of the cliffs before the promenade was constructed shows the excellent exposures which once existed and the natural supply of sand from the Eocene strata to the beach. At the top of the cliff there is a well-defined bed of Pleistocene Plateau Gravel (Boyn Hill Terrace of Green, 1946 or Terrace 10 of Bristow et al., 1991), formed in periglacial conditions. It is between 0.91m (3 feet). and 2.44m (8 feet) in thickness and rests on an eroded surface of Boscombe Sand (Ord, 1914, Bristow et al., 1991). A thin deposit of blown sand above the gravel is the result of wind action on the cliff raising sand onto the cliff top. This happens at the present time at Hengistbury Head, where even gravel is blown upwards.

As Ord (1914) commented, from Bournemouth Pier the cliffs rise gradually to the east averaging a height of 24m (80 feet) to 27m (90 feet), unbroken by any chine or valley until Boscombe Pier is reached. Between the Zizag and a point 200m east of the lift there are remains of marine molluscs (Ostrea, Arca, Modiola, Tellina, Natica and "Cerithium") and traces of a shore crab. These are in the 'Bournemouth Marine Beds' which are now classified as the uppermost part of the Branksome Sand. Teredo-bored wood occurs in the same area. There are clay lenses with leaves of Podocarpus(Podocarp tree), Lygodium, Hewardia and remains of some unidentified flowering plants (preserved at the Bournemouth Natural Science Society). Ferns, including Polypodium and Osmundia, have been found in the Bournemouth Freshwater Beds (lower part of Branksome Sand and the Poole Formation of Bristow et al., 1991). Some 200m east of the lift at the foot of the cliff some dark-grey, pyritic clay yielded many specimens of a fan-palm, probably a Sabal (Ord, 1914) a genus also found at Studland (Lyell, 1871). Nearby a 3m thick sand bed was seen to contain numerous irregular large mud-clasts ("irregular masses of brown clay"), presumably derived from the erosion of a river bank. Near this in white sand were rolled, thin, clay flakes that had preserved the impressions of leaves with good venation (Ord, 1914).

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7.7a LOCATION - 7a - East Cliff: Bournemouth Pier to Boscombe Pier - Sulphide Oxidation, Branksome Sands

Jarosite on the surface of a pyritic bed, Branksome Sand Formation, East Cliff, Bournemouth

In the lower part of the cliffs to the east of the East Cliff Lift some yellow or dirty white efflorescences of sulphate [sulfate] minerals are noticeable. These have resulted from the effects of sulphuric acid which was derived from the oxidation and leaching of pyrite in the clays. Although probably less conspicuous now, some is still visible above the promenade, as shown in the photograph above. In particular, the bright yellow mineral jarosite is a sulphate weathering product, often mistaken for sulphur. It is common on pyritic parts of the cliffs of Dorset and Hampshire (and has been found on Mars!). There is often some association with limonite or goethite which is hydrated ferric oxide derived from the oxidation of the ferrous sulphide. The white or greenish melanterite, (hydrated ferrous sulphate) has also been recorded here (Ord, 1914 ). It is associated with a gummy resinous relic of the vegetation of the Eocene and this is known as succinate. Alum Chine, further west, takes its name from the sulphates present on the cliff. The melanterite, formerly known as "copperas" (there is probably no copper within the sulphate, though) or "alum" was used by tanners, dyers and ink manufacturers, the working of these being an early Bournemouth industry (King, 1974). It was also worked on Brownsea Island and the source pyrite can still be found on the beach there.

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[addition 26 June 2016]

LOCATION:

Bournemouth Pier to Boscombe Pier

Chalybeate Springs (Ochre Springs) and Boscombe Spa

A concentrated variety of Boscombe Spa Water emerged from the cliffs at Toft Zigzag west of Boscombe Pier, Dorset, 4th July 2008

The Toft Zigzag Chalybeate Spring at the path down the cliff near Boscombe, Bournemouth, Dorset, in good condition after heavy rain in early 2014

The quantity of pyrite in the Branksome Sand Formation has produced not only precipitated mineral encrustations, but also brown flowing springs (ochre springs) with ferrous sulphate concentrations. These are chalybeate springs, and are similar to those which have been in use in places such as Tunbridge Wells since the 17th century for medical purposes (supposedly for stomach complaints, constipation, tape worms and skin infections etc). They are common in the Bournemouth area and on the Isle of Wight. The most notable in the region is the Irons Well near Fritham in the New Forest (on Eocene strata of similar age). Shown above is seepage of ferrous sulphate solutions from pyritic, argillaceous sands in the Branksome Sand Formation of the cliffs to the west of Boscombe Pier, at the Zigzag. This seepage is like that which came from the same formation at Boscombe Chine and was used as a spa.

The Boscombe Spa was a ferruginous (chalybeate) spring near Boscombe Chine and Boscombe Spa Road. Physicians recommended their patients to drink the waters for their mineral content, which were said to contain properties similar to those of the Harrogate water (Edwards, 1981, p. 55, et. seq.). Sir Henry Drummond Wolff erected a small, thatched building around the spring, but this was destroyed in 1923. The water was also sold, bottled, as aerated table water and its taste was said to be similar to Seltzer's water, an effervescent mineral water that was considered a fashionable drink. Perhaps, dilution and carbonation rendered the natural brown, rather acid fluid, more agreeable!

See below, for information on the Southbourne Chalbeate Spring.

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7.7b LOCATION - 7b - East Cliff:

The Beach - Strange Upward Movement of Piles in Groynes (and some discussion on beach replenishment)

A distorted groyne, with rising piles, between Bournemouth Pier and Boscombe Pier, Dorset, 4th July 2008

Between Bournemouth Pier and Boscombe pier at a particular site an unusual phenomenon had been reported. This had been noticed by the Bournmemouth Council, civil engineering authorities. I was informed about this but I had no immediate ideas as to the cause.

Some piles within the groynes had moved upwards, separately from others. This movement has diplaced the intervening, horizontal boards and produced gaps. These had been subsequently repained by adding sheets of timber. The reason for this peculiarity was not known. A student with Ian West examined the peculiar piles, but were unable to come to any conclusion regarding the localised upward driving force (or subsidence of adjacent piles?). The matter was not resolved. Now (2016) the beach is different. There has been further beach replenishment. The matter has not been studied further and remains a mystery.

Some possible mechanisms are:

1. Ground Settlement. This might seem more likely. It is not uncommon to get ground movement next to engineering works on strata. However, no activity on any large scale seems to have taken place here. Nothing drastic has happened to displace the underlying clays of the Branksome Sand Formation.

2. The piles may be of different timbers.

3. The geological substratum under the groyne may be different with some piles in the sand of the Boscombe Sand Formation and some in a channel-fill clay of the same formation.

So the the small mystery is unexplained, but worth recording in case it occurs again, and in case some explanation arises.

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7.7c

Bournemouth Pier to Boscombe Pier

Soft Sediment Deformation in the Branksome Sand Formation
("Bournemouth Marine Beds")

(Probable effects of an earthquake during the Tertiary phase of the English Channel Inversion Structure)

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Location and Introduction

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The Earthquake Bed at the East Cliff, Bournemouth, Dorset, showing a well-developed, water-escape structure

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Eocene uplift of the Inversion Structure - soft sediment deformation (palaeoseismicity?) and a pebble beach development, with Maastrichtian pebbles from the south; evidence from Bournemouth, Dorset, in a cliff section

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The location of soft sediment deformation structures in a sand body within the Branksome Sand Formation, Bournemouth, Dorset

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A broader view of the location of the soft-sediment deformation structures, Branksome Sand Formation, East Cliff, Bournemouth, Dorset, as seen at low tide in February 2004

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Penecontemporaneous erosion of sandstones showing soft sediment deformation, Branksome Sand Formation, East Cliff, Bournemouth, Dorset, 13th February 2014

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The location of very interesting sedimentary structures in the Branksome Sand Formation of East Cliff, Bournemouth, is a short distance east of the Cliff Lift. I hope that this exposure will be conserved and not built over.

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Details (7.7c)

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Soft sediment deformation structures, including pillar and flame, in the Branksome Sand Formatin, Bracklesham, Eocene, East Cliff, Bournemouth, Dorset, 13th February 2014, original photograph, without alteration or emphasis

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Soft sediment deformation structures, including pillar and flame, in the Branksome Sand Formation, Bracklesham, Eocene, East Cliff, Bournemouth, Dorset, 13th February 2014, structures emphasised

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Soft-sediment deformation, an isolated flame structure, Branksome Sand Formation, Bournemouth, Dorset, 13th February 2014

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A recumbent anticline, one of the soft-sediment deformation structures in the high Branksome Sand Formation (Bournemouth Marine Beds, East Cliff, Bournemouth, Dorset, photographed in 2004

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There are some very interesting, soft-sediment sedimentary structures in the Branksome Sand Formation (Bracklesham Group) and quite conspicuous in the Bournemouth cliffs. The structures are present in Bournemouth East Cliff, west of Tosh Zigzag, and east of the cliff lift.

These structures are similar to those described by Kundu et al. (2011), Palaeoseismicity in relation to basin tectonics as revealed by soft-sediment deformation structures of the Lower Triassic Panchet Formation, Raniganj Basin (Damodar Valley), Eastern India. Those soft sediment deformation structures were attributed to the action of earthquakes. There is good reason to ascribe the Bournemouth examples to palaeoseismicity too, because of the sedimentological and palaeogeographic studies of Plint (several papers) and the coincidence of date of occurrence of these structures to initial Tertiary tectonism, both in the Isle of Purbeck and the Isle of Wight (See papers of Daley and others). [This section will be expanded]

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Unusual soft-sediment deformation structures in a sand body of the Branksome Sand Formation, East Cliff, Bournemouth, Dorset

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A possible water escape, burst-through structure, high Branksome Sand Formation, East of Toft Zigzag, East Cliff, Bournemouth, Dorset, 8th March 2014

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Penecontemporaneous contortions in the Boscombe Sand Formation, East Cliff, Bournemouth, Dorset, with at least one possible water-escape structure

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Shown above are early sedimentary structures in sand bodies of the hot and humid Poole Delta, during its later stages. Penecontemporanous, sedimentary sand structures, like this, are common in the top Branksome Sand Formation. They occur again in the Lower Barton Clay Formation at Hengistbury Head and at Friars Cliff, near Highcliffe. More examples are shown below, in older photographs.

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The exposures of slumped  Branksome Sand Formation, near the East Cliff Lift, Bournemouth

Liquifaction or slumping and channeling in the Branksome Sand Formation, East Cliff, Bournemouth

Closer view of liquifaction or slumping in the Branksome Sand Formation , East Cliff, Bournemouth

Slumped sandstone with truncated top, Branksome  Sand Formation, East Cliff, Bournemouth

Just east of the East Cliff Lift there are well-developed liquifaction or slump structures in friable sandstones of the Branksome Sand Formation (Bournemouth Marine Beds). Channels have been cut and these are usually filled with carbonaceous, laminated sandy clays of a chocolate-brown colour. They seem to show some rhythmicity. Lignite is often present in these beds and in some cases they may be representives of the leaf beds in which the interesting and important Bournemouth Eocene flora has been found. This unit, was previously known as the 'Bournemouth Marine Beds' because of the limited assemblage of marine molluscs which have been found. Plint regarded this as his sedimentological unit G, and the British Geological Survey included these strata within the Branksome Sands, as the topmost part.

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7.8 LOCATION - 8 - East Cliff Lift Area

More text on East Cliff Lift area may be added in due course. It is an interesting area with the Boscombe Sand Formation above the Branksome Sand Formation in the cliff. It is a notable area for fairly small, cliff falls or "landslides", but which are to some hazardous because this is a much used part of the Bournemouth coast. The landslides are discussed in a separate section. This is the main location for cliff falls. There was a notable one in 2014. Later, in 2016, a particularly bad collapse destroyed the cliffs and rock armour etc adjacent to the East Cliff Lift, and it is damaged and out of use at present (16th June 2016).

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7.9 LOCATION - 9 - Approaching Boscombe Pier from the west.

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Eastern cliffs of Bournemouth, near Boscombe Pier, in or about 1903, before the promenade was built here.

The image above, based on a postcard, shows the beach and cliffs just to the west of Boscombe Pier, but before the promenade was built. Notice how the Boscombe Sand Formation in the upper part of the cliff could and did supply sand to the beach by minor cliff falls. When the promenade was built, it was placed too close to the foot of the cliffs. The result of this is that occasional cliff falls, such as have happened in the vicinity of the East Cliff Lift in 2014 and 2016, spill sand at high velocity onto the Undercliff Drive. There is no gap next to the cliff to receive fallen debris. Fortunately few people walk close to the cliff and the falls are sometimes at night, so no-one has been injured, at least as yet. There is a small potential hazard to people and to the road-train if they are close to the cliff, but the falls are usually rare and limited in size.

[More text on approaching Boscombe Pier from the west to be added.]

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7.10 LOCATION - 10 - Boscombe Pier.

Looking towards Boscombe Pier, with a view onward to Hengistbury Head, taken from a hotel balcony on the East Cliff, Bournemouth, Dorset, on the 25th April 2007

From Boscombe Pier eastward there are, here and there, exposures of the Boscombe Sand Formation which is here (further east) lower in the cliff. Close to the pier there has been much building and the covering up of natural cliff features. An artificial reef, that failed to work properly, has been constructed in the sea here, and is discussed in a separate section. Buildings (flats) have been constructed just to the east of the pier, so that this area has become rather urban. It may be a good place for surfers. Others may prefer to walk on eastward, where the scenery becomes a little more natural. For the geologist, there are still some useful exposures but they are limited and not very good.

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Subsection 7.10a
Boscombe Pier to Southbourne; An Ancient 'Chesil Beach'

Eocenen pebble beach deposits with Pleistocene gravel above, Fishermans Walk, Bournemouth, Dorset

Old beach gravel of rounded flints east of Boscombe Pier, Dorset

Battered beach pebbles from the Boscombe Sand, east of Boscombe Pier, Dorset

A flint cobble from the Boscombe Sands Cobble Bed, with very well-developed percussion marks from impacts on ancient, Eocene

In the upper part of the cliff, a moderate walk east of Boscombe Pier, there is an interesting bed of very rounded flint pebbles in the Boscombe Sand. These are characterised by the presence of percussion marks, showing that they have been thrown against each other and rolled in the surf of an Eocene storm beach. They resemble some of the largest pebbles of the Chesil Beach in shape, size and markings but are mainly flint and do have any obvious large quantity of exotic material (the Chesil Beach pebbles are mainly of chert, flint and quartzite). No systematic search for unusual material has been made, though. Some of the clasts exceed in size those of the Chesil Beach and the wave action mau have been even more severe.

The overall upward trend in the predominantly deltaic Bracklesham succession at Bournemouth is towards more marine conditions and culminates in the fossiliferous Barton Clay. Here, east of Boscombe Pier we see the remains of a barrier beach subject to significant storm waves. It is very unlikely that the beach had a similar orientation to the present Chesil Beach, because the palaeogeographic maps show that the sea was to the southeast. The Chalk supplied the flint and the storm waves from the southeast battered the clasts on this delta-front barrier.

Incidently, Curry ound Maestrichtian foraminifera in an Eocene flint pebble on this stretch of coast, and that may provide a further indication of the palaeogeography. It has probably been derived from the uplifted English Channel Inversion during Eocene times.

Another feature of interest in the cliffs between Boscombe and Southbourne is the presence of "decomposed" flints. These are flint pebbles which have undergone partial, internal, dissolution and have been reduced to a white amorphous powdery substance that will leave a white mark on cloth (Ord, 1914; King, 1974). The solubility of silica, of which flints are composed, increases at very high and very low pH values, that is in very alkaline or very acid conditions. Either of these conditions could have caused the partial dissolution. The oxidation of pyrite, producing sulphuric acid, is most likely the cause, but the topic has not been researched in detail.

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Subsection 7.10b

[Boscombe Pier to Southbourne continued]

This stretch of cliff from Boscombe Pier to Southbourne shows Boscombe Sand over Branksome Sand (Bournemouth Marine Beds), with Plateau Gravel of Pleistocene age at the cliff top (western part is of Boyn Hill Terrace of Green, 1946 or Terrace 10 of Bristow et al., 1991). A mammoth tooth found near Boscombe Pier, is likely to have come from such gravel. It is in the Red House Museum at Christchurch (Lavender, 1985). Honeycombe Chine , a short distance east of Boscombe Pier, is of special interest and is dealt with below separately. The Boscombe Sand originated on a sea shore. It contains irregular layers of white and yellow sands mixed with beds of well-rolled flints. The shingle is banked up as if by waves coming from the east and King (1974) suggested the banks may have been formed offshore, as bars or shoals, and then driven inland as the sea flooded an area to the west.

Ord (1914) commented that in some of the lower beds (Branksome Sands - Bournemouth Marine Beds) there are occasional fruits resembling Petrophiloides, Cucumites and a Hightea (of Bowerbank) which were found by Gardner. Nearer to Southbourne Seqouia (i.e.related to the California Big Tree or Wellingtonia and the California Redwood Tree) has been recorded. In a bed of sand near the same spot an American form of Cactus has been found (Ord, 1914).

Plint (1980; 1982; 1983a; 1983b; 1988) has provided much information on the sedimentology of the strata and further detail. For this area, east of Boscombe Pier, Bristow et al. (1991, p. 62) have described three sections. Possible Ophiomorpha burrows occur in the lower part of some brown lignitic clay at Southbourne.

This stretch of cliff from Boscombe Pier to Southbourne shows Boscombe Sand over Branksome Sand (Bournemouth Marine Beds), with Plateau Gravel of Pleistocene age at the cliff top (western part is of Boyn Hill Terrace of Green, 1946 or Terrace 10 of Bristow et al., 1991). A mammoth tooth found near Boscombe Pier, is likely to have come from such gravel. It is in the Red House Museum at Christchurch (Lavender, 1985). Honeycombe Chine , a short distance east of Boscombe Pier, is of special interest and is dealt with below separately. The Boscombe Sand originated on a sea shore. It contains irregular layers of white and yellow sands mixed with beds of well-rolled flints. The shingle is banked up as if by waves coming from the east and King (1974) suggested the banks may have been formed offshore, as bars or shoals, and then driven inland as the sea flooded an area to the west.

Ord (1914) commented that in some of the lower beds (Branksome Sands - Bournemouth Marine Beds) there are occasional fruits resembling Petrophiloides, Cucumites and a Hightea (of Bowerbank) which were found by Gardner. Nearer to Southbourne Seqouia (i.e.related to the California Big Tree or Wellingtonia and the California Redwood Tree) has been recorded. In a bed of sand near the same spot an American form of Cactus has been found (Ord, 1914).

Plint (1980; 1982; 1983a; 1983b; 1988) has provided much information on the sedimentology of the strata and further detail. For this area, east of Boscombe Pier, Bristow et al. (1991, p. 62) have described three sections. Possible Ophiomorpha burrows occur in the lower part of some brown lignitic clay at Southbourne.

Details - Honeycombe Chine - Nipa Palm Nuts

Honeycombe Chine, Boscombe, Bournemouth, Dorset, with the Nipadites Bed at the base, as seen in 1914

Nipa palm nuts

Nipa fruit, Nipa burtinii, from the swamp palm occurs in the London Clay of the Isle of Sheppey and in the Eocene Bracklesham Group at Honeycombe Chine, Boscombe, Bournemouth, Dorset

Honeycombe Chine was once a small and attractive chine about 200m to the east of Boscombe Pier. It is shown here as it was sometime before 1914. It has been destroyed by coastal development and is now an ugly car park. It was once notable for the interesting remains of nuts of the stemless palm - Nipa (Ord, 1914). This plant is related to coconut palms and to Pandanus, the screw-pine (Lyell, 1871). This plant is abundant in parts of the Mekong Delta in Vietnam and other tropical and subtropical swamps, often associated with mangroves. At the present day Nipa is a plant highly valued by the villagers of coastal areas. It is found in river estuaries, tidal lands near the sea and on the soft muddy banks of small water-ways. It grows best in freshwater environments but can tolerate some level of salinity in modern deltas which may be rather like the ancient Eocene Poole Delta of Bournemouth area (Bamroongrugsa and Kwanjareon, 1998) .

The Nipa nuts occur in clays within the Branksome Sand, the Bournemouth Marine Beds in older terminology, at the foot of Honeycombe Chine. It is a bed of dark reddish sand, about 0.9 (3 feet) thick and situated about 7.m (23 feet) above beach level. The remains are of the Nipadites fruit, and consists of its remains mixed with rounded vegetable pellets and debris, occurring in layers, perhaps washed together by tidal action (Ord, 1914). The casts of the nuts rarely occur either east or west of this point. Elsewhere fruits of Nipadites occur in the (slightly older) Wittering Formation of the Bracklesham Group of Wittering, Bracklesham Bay, Sussex (Curry et al.) and in the London Clay of the Isle of Sheppey. The Bournemouth specimens are mostly of Nipadites parkinsoni . The fruits have germinated and only the hollow pericarp is found, filled with white sand (for more details see Morris, 1912). The Nipadites bed could be traced for a considerable distance eastward although it rapidly became unfossiliferous.

Lyell (1871) commented on Nipa mainly with reference to the occurrence in the London Clay of the Isle of Sheppey, Kent. There the greatest number of fruits occur in the uppermost 15m (50 feet) of the formation and are mostly found on the beach where the sea has washed away the clay. Lyell stated that Nipa is now only found in the Molucca and Philippine islands, and in Bengal. Dr Hooker had apparently observed floating in the branches of the Ganges Delta such numbers of the large nuts of Nipa fructicans that they obstructed the paddle-wheels of the steam-boats.

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Subsection 7.10b
Boscombe Pier and the Artificial Surf Reef (Surf Reef 7.10b)

Boscombe Pier, a popular area for surfing, east of Bournemouth, Dorset, as seen, looking east, from the west side of the pier on January 26th 2009

Boscombe Pier, Bournemouth, Dorset, 6th July 2008, with strong winds and large waves

Boscombe Pier provides a good view of the Bournemouth coast. The west side of the pier is like much of the Bournemouth beach area with an Undercliff Drive, and with a wide replenished beach of sand and pebbles. There is an exposure of the Branksome Sands in the lower part of the cliff, as discussed above.

A short urban stretch of coast with new flats under construction east of Boscombe Pier, Bournemouth, Dorset, 6th July 2008

Approach to Boscombe Pier, Bournemouth, Dorset, 6th July 2008, showing Sea Road and the coast from Boscombe to Hengistbury Head

The east side of the pier is relatively urban and there was even the construction, taking place in 2008, of a large block of flats on the cliff. These flats are now completed. The place is not without interest, though. Although the natural features of the coast here have long been destroyed, the replenished beach contains some interesting pebbles. This sand and pebble deposit here has come from off the Isle of Wight. Most of the pebbles are of subangular flint, but there are many that are of a micritic limestone, probably a hard variety of Chalk. There are occasional bivalve shells present in this. In addition there is some Upper Greensand, and a few other, as yet unidentified rock types. The sand contains many dark grains, possibly of limonitic oolite derived from the Lower Greensand.

Surfers enjoy the pleasures of large waves at Boscombe Pier, Bournemouth, Dorset, 6th July 2008

A miniature stony desert, reg or gibber plain of dredged, replenished sand and gravel at Boscombe, Bournemouth, Dorset, 6th July 2008; this is stock material for the artificial reef

Loss of the stock of dredged sand and shingle, east of Boscombe Pier, Bournemouth, Dorset, 26th January 2009

At one stage sand and gravel, intended for the artificial reef was dumped here. The beach is probably different now, and the situation may be complicated by artificial transport of beach material from east to west by dumper trucks. This is intended to compensate for continual loss of beach sediment by longshore drift towards the east (see recent press report on this topic). However, there has been, at times, much aeolian action and sand blown off the beach, and mostly transported in an easterly direction. As the sand departed the pebbles remained. This is a common feature of deserts showing deflation. This has been seen east of Boscombe Pier in 2008, but may have been a temporary occurrence.

A small sand dune develops against deckchairs near Boscombe Pier,  Bournemouth, Dorset, 6th July 2008, showing eastward transport of sand

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Subsection 7.10c

Boscombe Pier - Artificial Surf Reef - Introduction (Surf Reef 7.10c)

The artificial surf reef east of Boscombe Pier, Bournemouth, Dorset, as seen by helicopter on the 6th July 2013.

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Canoes cross the area of the Boscombe Surf Reef, near Boscombe Pier, Bournemouth, Dorset, as seen from a helicopter, 6th July 2013

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In 2008 there was optimism about success of an artificial surf reef at Boscombe; however, later it was damaged, and it was closed in 2011. In 2013, the Director of the firm that built it seems to have gone missing.

Bournemouth Makes Waves with Surf Plan (BBC News, Bournemouth, 19th August 2008. By Gavin Stamp, Business reporter, BBC News, Bournemouth.)
Surfers and swimmers on Boscombe beach.

Bournemouth does not see itself competing directly with Cornwall. ... Soon the town will be hoping to make a few waves of its own as it looks forward to finally welcoming Europe's first artificial surf reef. The plan to build the reef off Boscombe beach, just over a mile east of the town's main seafront, was first mooted nearly a decade ago. Weather permitting, the structure should finally be installed by the end of October... "The weather has not been kind to us," says Jon Weaver, marketing and events manager at Bournemouth Tourism, reflecting on the recent windy conditions which have held up progress on the venture. Praying for calm: All concerned with the 2.6m pound project are hoping for a calm spell to allow the main phase of the complex engineering process - in which layers of matting half the size of a football pitch, with sandbags attached, will be laid on to the sea bed and then secured - to begin. "For laying each section of the reef, we need it perfectly flat," explains construction manager David Neilson. He heads a team of divers, boat crew and pump operators who have come over from his native New Zealand to do the work. Pile of sand on Boscombe beach waiting to be pumped.

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Subsection 7.10d (- Surf Reef 7.10d)

Boscombe Pier - Artificial Reef - Out of Action - 2011.

Later Press Discussion - 2013

[Extract from BBC report in 2013, after the reef went out of action in 2011.]

Boscombe surf reef director Nick Behunin 'cannot be found'.
Photographs of Nick Behunin are available on Google; just click in the name. Nick Behunin's New Zealand-based company ASR Limited helped construct the 3.2 million pound reef in 2009. Liquidators for the New Zealand-based company which built Europe's only artificial surf reef are yet to locate its director. ASR Limited, which built Boscombe surf reef in Dorset, was placed into liquidation in September.

Nick Behunin's company oversaw construction of the 3.2 million pound reef which has been out of action since 2011. Bournemouth Borough Council said it registered a claim to be a creditor with liquidators in February. The council is pursuing an insurance claim for damages after two of the reef's sand-filled bags were struck by a boat propeller in May 2011.
Liquidators Pricewaterhouse Coopers' six monthly report, released through Companies House in New Zealand, revealed attempts to contact ASR's majority shareholder Sealutions LLC have also been unsuccessful. Since being placed in liquidation, NZ dollars 7,447 (4,128 pounds sterling) has been raised from the sale of the company's remaining assets consisting of two cars, a trailer and various office equipment.

Dan Jenkins, .... said: "It's a real shame. The longer the reef sits idle, the more it will deteriorate... There's a host of local contractors out there who were involved in the original build and could easily undertake the repairs needed."
The reef, made of 55 giant sand-filled bags 740ft (225m) out at sea, opened in November 2009 after lengthy delays and running over budget.

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7.11 LOCATION - 11 - Honeycombe Chine

Text on Honeycombe Chine to be added.

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7.12 LOCATION - 12 - Honeycombe Chine to Southbourne

Text on Honeycombe Chine to Southbourne to be added.

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7.13 LOCATION - 13 - Southbourne

Chalybeate Spring

The chalybeate (Fe - iron) spring at Southbourne (Brownen, 1914; Kingzett, 1884) was discovered during excavations for a sea wall and esplanade and was situated about 3m. below the beach. It had an inky taste and resulted from the action of fresh water on the iron and aluminium in the strata. Its medicinal properties were said to be "of a pronounced and valuable character and would be beneficial in many cases of anaemia". A well was constructed and it was hoped that a successful spa would result (King, 1974 ). Another iron spring was situated at the southern entrance to Boscombe Gardens.

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7.13a LOCATION - 13a - Southbourne Coast Erosion
(and the Loss of the Pier and the Old Promenade)

[See also the:
Hengistbury Head Geology webpage]

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An old topographic map of Southbourne, of 1920s and 1930s, probably showing relics of the three houses built at the foot of the cliff, but with no remains of the Esplanade or Southbourne Pier shown

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A redrawn old geological map of Southbourne in about 1900 when it had a pier and a first promenade, both of which were destroyed by the large waves which can hit Southbourne, a place less protected against storm erosion than is the main Bournemouth Beach

Southbourne is a pleasant place and I have lived there for many years, although not at present. My father had a house built, wisely, at the northern end of Wildown Road, a safe distance from the cliffs. Back in the 1950s it was a bad place for coast erosion, although it was worse in the past when Southbourne Pier and the Esplanade were smashed by the sea in about 1900. In the 1950s the coast here was still subject to much erosion (and there was also the problem of the discharge of raw sewage which washed back onto the beach). It is not surprising that Southbourne was a place of erosion, because, Hengistbury Head, not far away, has lost about half its width in historic times. Maps and old photographs here show something of the erosion taking place at Southbourne, although it was never on an enormous scale, perhaps for a time about a metre a year or so, not unlike the more famous erosion site of Barton-on-Sea.

At the moment, Southbourne has a reprieve from erosion. The reason is that huge quantities of sand are regularly (about every five years) dumped on Bournemouth beaches as "Beach Replenishment". The prevailing longshore drift is from west to east, so naturally a large proportion of this material is drifted towards Southbourne. Is is very likely that this has greatly slowed or almost stopped the natural erosion here. Thus houses at Southbourne, which as a boy I imagined would sooner or later fall over the cliff, are still there in the year 2016!

So is there no problem? This is not completely true. If some random event caused the country to go into a state of relative poverty, then the beach replenishment might be reduced or stopped, and eventually the feed of surplus sand would cease. The cliffs to the west are protected by a sea wall and they are largely overgrown. They supply very little now and they could not keep the Southbourne beach stable because there are insufficient cliff falls at Bournemouth (occasional ones occur near the East Cliff Lift, but they do not supply much sand to the beach). So there is not a substantial threat of high coast erosion, but it could occur during a major storm, or because of a cessation of beach replenishment at Bournemouth. There is no detailed undestanding of just what damage a repetition of the 1 in 250 year storm could do. This storm, when it comes, is considered as quite likely to flood the low ground between Southbourne and Hengistbury Head as the sea-level rises and the great waves pound in. It is unlikely to occur my lifetime, but it will come one day, and you find the possibility taken into account in official plans and schemes for the long-term future. Weymouth is taking precautions against large-scale sea flooding. Portsmouth has always been at risk because part of it, even now is continually pumped out. Sandbanks is obviously the special case, in part a possible disaster area that is best avoided in great storms, even though it is protected from direct action of the southwesterly winds. Southbourne is at some risk of major coastal retreat in a great storm, but the extent of coastal retreat is not known. If you are some way back from the coast and on higher ground there is little to be concerned about, and although major sea-flood damage could occur one day, it may never happen in your lifetime.

The photographs here show the effect of occasional storm activity, but nothing dramatic like the not of the great 1 in 250 year storm. Moderately bad storms can cut back the coast here, but are less likely to do while Bournemouth pumps sand onto the beach on a large scale.

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An old advertisement for a foolish scheme to build houses on a esplanade at eroding coast of Southbourne-on-Sea, Poole Bay, Bournemouth

At the old Southbourne Esplanade or Promenade in about 1899, houses were unwisely built at the foot of the cliff, at the level of the Promenade, and even before the intended row of buildings was completed the sea wall began to collapse under storm waves

A view from the cliff top of the coast erosion and destruction of the old sea wall and promenade at Southbourne, Bournemouth, Dorset, probably in about the late 1920s

Coast Erosion of the old sea wall and promenade at Southbourne, Bournemouth, Dorset, the state in about the late 1920s

Southbourne cliff collapse near the stepped huts, at the site of the former, 1900, sea-front houses, with fallen, concrete gun emplacements from the Second World War, 1940s, on the beach, photograph in about 1951

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Now for further detail. An esplanade was constructed at Southbourne in 1885 and a pier in 1888. An exceptionally ferocious storm on the 28th December, 1900 breached the sea-wall and severely damaged the pier. Houses on the esplanade were subsequently demolished and the pier dismantled in 1907 (Young, 1989). By 1913 the relics of the esplanade were just rocks at the foot of beach and the cliffs had retreated. The coast here is more exposed to southwesterly storms because it has less protection from the Swanage promontory than has the central and western part of the Bournemouth coast, and therefore more coast erosion can be expected.

Erosion was still quite severe here in the early 1950s, when the author lived in Wildown Road (Broadway end). Remains of the old wall still existed as rocks in the sea. The cliff top houses seemed to be at, perhaps, some future risk. However, beach replenishment at Bournemouth changed the situation. Much sand was lost to the east because of the prevailing southwesterly winds. This drifted to Southbourne and greatly reduced coast erosion. This situation continues, but if, in the future there is some reason (such as a financial crisis) for ceasing the replenishment at Bournemouth, then Southbourne cliffs will come under threat once more.

Some notes on the Southbourne promenade from Young (1989) are given here:

Work on the new Southbourne Promenade commenced in the summer of 1883, long before Bournemouth had a promenade. It consisted of a curved roadway, forty feet wide, with a pedestrian pathway sixteen feet wide on the seaward side, the whole extending for about one third of a mile. At the centre of the promenade was a short circular bend seaward, which might form an entry for a possible future [there was then a pier at Southbourne, destroyed by the sea in due course]. The sea wall rose to about eight feet above beach level, with foundations from six to nine feet below it.... There was a central approach road 100 feet wide with an easy gradient for carriages. The whole of the works cost about 18,000 pounds [these notes are from Young]. On the 1st August 1885 the Christchurch Times reported that the extensive esplanade works at Southbourne were completed, ... and there would be a formal opening ceremony. ... Twenty-four bathing boxes were provided at a fee. In the late 1890s they were swept out to sea in a September gale.

[the following slightly modified extract is after Young, J.A. 1989]

"After Christmas 1900, the closing days of December brought gales and a storm of exceptional ferocity swept over the country on the 28th December. At Southbourne the sea wall was breached and the Southbourne Pier damaged severely; further storms early in January extended this damage. Although the promenade was not beyond repair, unfortunately it was more than the resources of the Land Company could meet, as the Company finances had been stretched to breaking point. Still more damage was done to the Southbourne Undercliff in 1902, and this coupled to the financial position, led to the Undercliff Parade being abandoned; the Southbourne Pier was never repaired."

[Extract from Bright's Guide to Bournemouth, 1891, in Young (1989)]
"The rapid progress of Southbourne may be judged from the fact that whereas some fifteen years ago, it had neither a name nor a road, much less a house, it now possesses a handsome Church, a large Hotel, numerous private residences and lodging houses, shops, Post and Telegraph Offices, a valuable Chalybeate Spring, and last, but not least, a magnificent Undercliff Esplanade and Sea Wall, to which a well-designed iron Pier of about 300 feet is now attached." [Obviously, the Chalybeate Spring, also mentioned above, is of course of geological interest.]

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The future regarding coast erosion at Southbourne is that it will remain low as long as Bournemouth tips sand on the beach at considerable cost. If there less spare wealth available at some time in the future, the first effects will be less at Bournemouth than at Southbourne and Hengistbury Head. These eastern areas will be severely eroded. It is only sensible that is in existence a map indicating the possible overflow of the sea between Southbourne and Hengistbury Head (causing incidently destruction at Mudeford etc). With rising sea-level and changes in the climate this is extremely likely to take place at some unknown date. A major tsunami could have a similar effect, but these are very rare in this area (last large one - 1775). While people only live only a very short time of about 100 years or less the long-term events seem relatively unimportant. In the future, if and when human life is extended to several hundred years, the natural frequency of coastal storm events will be better understood. At the present we do not have an appropriate time perspective regarding the natural inland advance of the English Channel coast. The "butterfly view" of not much is happening is still widespread, and many people actually like to live near the cliffs of an expanding sea!

[PS. Making a recess in the cliff and then constructing a building with a base level near that of the promenade is not normal at Poole Bay, i.e. in the Bournemouth area. However, it does seem to have actually happened again in modern times at Boscombe, in this case, near the intended surf reef. It is at a relatively safer place, however, that is protected to some extent by regular beach replenishment. The location with a long-known history of survival, with the old Boscombe Pier still there nearby. The place is not known for major coast erosion. Of course, in the long term general rising sea-level problems are expected in the bay in general and, of course, there is the usual risk of arrival of a great 1 in 250 year storm.]

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7.14 LOCATION - 14 - Hengistbury Head

For the main information on this locality, please go to separate webpage on Hengistbury Head - see:

Hengistbury-Head-Geology

[Supplementary Note re Hengistbury Head and Bournemouth
Hengistbury Head is affected by Bournemouth Sea Defences, and this is not surprising. Rapid erosion has long been a problem at Hengistbury Head, and the promontory is much smaller than in the past. Gardner (1879) refers to a loss of 100 yards in 30 years (i.e. roughly 3m per annum, similar to the maximum figure for Barton-on-Sea). A coastguardman estimated that 60 yards had gone in 16 years (almost 4m. per annum). Hengistbury Head does not suffer rapid erosion now, not at all, because the regularly replenished sand from Bournemouth travels by longshore drift east to Hengistbury Head. I know, myself, from living at Southbourne, about 50 years ago, that rapid erosion was common there and Hengistbury Head in the past.

Now the cliffs of Bournemouth are no stronger or more resistant than the cliffs of Hengistbury Head and Southbourne. There are differences though. The Bournemouth cliffs are more protected from southwesterly storm winds and waves by the Isle of Purbeck than is Hengistbury. The sea-wall and promenade at Bournemouth was built in 1914.]

Rapid erosion has long been a problem at Hengistbury Head, and the promontory is much smaller than in the past. Gardner (1879) refers to a loss of 100 yards in 30 years (i.e. roughly 3m per annum, similar to the maximum figure for Barton-on-Sea). A coastguardman estimated that 60 yards had gone in 16 years (almost 4m. per annum). Hengistbury Head does not suffer rapid erosion now, not at all, because the regularly replenished sand from Bournemouth travels by longshore drift east to Hengistbury Head. I know, myself, from living at Southbourne, about 50 years ago, that rapid erosion was common there and Hengistbury Head in the past.

Now the cliffs of Bournemouth are no stronger or more resistant than the cliffs of Hengistbury Head and Southbourne. There are differences though. The Bournemouth cliffs are more protected from southwesterly storm winds and waves by the Isle of Purbeck than is Hengistbury. The sea-wall and promenade at Bournemouth was built in 1914 (and is not popular with geologists!).

Prior to that the erosion was probably fast and the sandy cliffs supplied the sand to Sandbanks and on to Studland. The cliffs were not necessarily all publicly accessible in Victorian times. There were private estates on the cliff top. There was an iron ladder down the cliff at one point between the present locations of Bournemouth and Boscombe piers. Lord Portman, who at one time lived in Portman Lodge, Exeter Road, arranged pile-driving at the foot of the cliff and built a concrete road up the face of the cliff (but I do not know where this was). The sand dunes at the top of the cliff and sand from the cliff were constantly falling on the concrete road according to Gardner writing in 1879.

A general feature of the Bournemouth cliffs, still visible today, is that the Branksome Sand Formation occurs in steeper, almost vertical lower cliffs, while the white and friable Boscombe Sand Formation slopes back at a considerable angle. This again was reported by Gardner (1879) and is still to some extent true today, although now the cliffs are mostly heavily vegetated.

In 1914 just before the sea wall was constructed, it was estimated that the coastal recession rate between Bournemouth and Boscombe was between 12 inches (30 cm) to 18 inches (45 cm) per annum Ord et al(1914) . It was only towards 1914 that the cliffs assumed almost vertical faces. Some fifty years earlier (about 1864) the cliffs were less steep and a lady on horseback rode up the cliff-face between the Zigzag and Boscombe [there is probably a byelaw against doing that now!]

Rapid erosion has long been a problem at Hengistbury Head, and the promontory is much smaller than in the past. Gardner (1879) refers to a loss of 100 yards in 30 years (i.e. roughly 3m per annum, similar to the maximum figure for Barton-on-Sea). A coastguardman estimated that 60 yards had gone in 16 years (almost 4m. per annum). Hengistbury Head does not suffer rapid erosion now, not at all, because the regularly replenished sand from Bournemouth travels by longshore drift east to Hengistbury Head. I know, myself, from living at Southbourne, about 50 years ago, that rapid erosion was common there and Hengistbury Head in the past.

Now the cliffs of Bournemouth are no stronger or more resistant than the cliffs of Hengistbury Head and Southbourne. There are differences though. The Bournemouth cliffs are more protected from southwesterly storm winds and waves by the Isle of Purbeck than is Hengistbury. The sea-wall and promenade at Bournemouth was built in 1914 (and is not popular with geologists!).

Prior to that the erosion was probably fast and the sandy cliffs supplied the sand to Sandbanks and on to Studland. The cliffs were not necessarily all publicly accessible in Victorian times. There were private estates on the cliff top. There was an iron ladder down the cliff at one point between the present locations of Bournemouth and Boscombe piers. Lord Portman, who at one time lived in Portman Lodge, Exeter Road, arranged pile-driving at the foot of the cliff and built a concrete road up the face of the cliff (but I do not know where this was). The sand dunes at the top of the cliff and sand from the cliff were constantly falling on the concrete road according to Gardner writing in 1879.

A general feature of the Bournemouth cliffs, still visible today, is that the Branksome Sand Formation occurs in steeper, almost vertical lower cliffs, while the white and friable Boscombe Sand Formation slopes back at a considerable angle. This again was reported by Gardner (1879) and is still to some extent true today, although now the cliffs are mostly heavily vegetated.

In 1914 just before the sea wall was constructed, it was estimated that the coastal recession rate between Bournemouth and Boscombe was between 12 inches (30 cm) to 18 inches (45 cm) per annum Ord et al(1914) . It was only towards 1914 that the cliffs assumed almost vertical faces. Some fifty years earlier (about 1864) the cliffs were less steep and a lady on horseback rode up the cliff-face between the Zigzag and Boscombe [there is probably a byelaw against doing that now!]

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8.1 LANDSLIDES AND CLIFF FALLS OF BOURNEMOUTH, OLD AND NEW - Introduction

this spring .. has of late years caused frequent landslips (Gardner 1879, p.225),

(the cliffs in 1879 at the site of the East Cliff Lift, where the Marine Clay, "b" in his section wedges out westward).

The short stretch of cliff between the East Cliff Zigzag and the East Cliff Lift area has been known since Victorian times as one of the places where the Bournemouth Cliffs are prone to landslides. There a marine clay wedges out from west to east just here and holds up water. There have been at least three cliff falls in this area; one in 2014, one in 2016 and an earlier one, in addition to the Victorian, pre-promenade falls. More details of the location and of the wedge-out of the marine clay will be added below, in due course. See Gardner (1879 and 1882). Unfortunately, the East Cliff Lift seems to have been sited at a less-stable part of the Bournemouth Cliffs, although it has certainly lasted a very long time! Note, however, the change or apparent change to a wetter climate now.

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We now return to modern times. There is a small amount of subject matter, in Guttridge (2009) relevant to occurrence of landslides in recent years between the Zigzag Path which is a short distance east of Bournemouth Pier and the Cliff Lift of the East. On page 29, this particular Zigzag path is shown in 1922 from a cliff top view [Francis Frith photograph No. 72683]. The general cliff situation is similar to that at present but there proportionally more exposure of Eocene sediments, particularly the Boscombe Sand Formation, and, of course, less vegetation. The promenade appears the same but there are beach huts directly on the sands, just in front of the promenade (which seems to be almost without traffic). The Zigzag path was built by Bournemouth Corporation in the winter of 1907-1908. It has not shown significant change, other than increase in vegetation. It has (in May 2015) only some very minor cracks in the walls of Purbeck stone. In general, in 1922, the steepness of the cliff and general aspect of the promenade seems much the same as in 2016. The major difference is that because of artificial beach nourishment the modern beach (May 2016) is two to three times the width of that in 1922. To see major differences it is necessary to go back before 1922.

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7x OIL AND GAS EXPLORATION AT AND NEAR BOURNEMOUTH

Bournemouth is fortunate in being close to large hydrocarbon energy resources, yet almost unaffected. The greatest and most productive oilfield in southern England is just south of Bournemouth beaches [and actually might be under them in part]. The important Wytch Farm Oilfield is under the sea to the south of the town. Official maps show that it has expanded eastward. However, at present, the maps do not indicate that it has expanded under the main part of Bournemouth. Sandbanks and Canford Cliffs have long been known to have industrial borehole and hydraulic fracturing ["fracing" in common terminology] taking place beneath them. This is nothing new; fracking south of Bournemouth has been taking place for many years, from back in the years when BP ran the huge Wytch Farm Oilfield, before selling it to Perenco UK. It has caused no trouble. The sea area just south of Bournemouth beaches is the largest scale, the oldest and most successful fracking area in Britain. It is not at all conspicuous because it is run from hidden works in forests on the south side of Poole Harbour. Nothing much can be seen or heard but the scale is great. It was always a proud boast of BP that more electricity is used for extraction in Poole Bay, just south of the Bournemouth beaches than for running Heathrow Airport. The oil and gas is piped through the edges of the New Forest to Fawley and Hamble in Southampton Water.

Now nothing is visible from Bournemouth because the oilfield is operated by horizontal drilling from concealed localities in forests on the south side of Poole Harbour. There are no drilling rigs on the Bournemouth coast. Although it has operated for many years there has been no problems or any known effect on the town. It is described here for information, but only in general terms.

It must be emphasised that there is no suggestion here, of course, that drilling rigs are likely to be seen at the town of Bournemouth. Wytch Farm Oilfield is offshore further south. If anything was found on land it would be presumably be extracted by the usual procedure of a long horizontal borehole from Wytch Farm. There would nothing unsightly at Bournemouth and most people would be unaware that any extraction or processes were taking place under the town (it would be rare to experience vibration, and very rate to experience a minor earthquake; I do not think that one has ever been reported with regard to Wytch Farm). Since the well-site is far from Bournemouth, contamination by oil or materials pumped down the well is unlikely in the holiday town. There has been a case (in the time of BP) of escape of fluids and pollution within part of Poole Harbour. I am not aware than there has been any escape into the open sea.

The main offshore oilfield is only known at the moment to overlap on to the coast at Sandbanks and at Canford Cliffs, although it is only reasonable that the oilfield could (but not necessarily will) expand further inland into areas may not yet have been fully explored). It is very unlikely that any oil or gas exploration in the Bournemouth area would hardly be noticed at the surface, even if it took place exploration, including 2015 locations, based on part of a government 2015 licence map (not shown here as highly accurate, only approximate.

Development of major oilfields in low coastal areas, near sea-level can produce some adverse effects, but, of course, most of Bournemouth is high so it might not be much affected. Subsidence has occurred in some oil and gas fields elsewhere after long periods of extraction. The most famous localities for this are Goose Creek in the Gulf of Mexico, USA, and the Gronigen Field in the Netherlands. Much information on this subject will be found on the internet. The main reservoir at Groningen is in the Permo-Triassic and thus comparable to the deep Sherwood Sandstone south of Bournemouth. No evidence is given here that subsidence will occur in the near future or later at the abandonment (if the large volume of cavity is not used for gas storage) of the Wytch Farm in the distant future. If it occurs offshore it will not be noticed. It might possibly affect low areas such as Sandbanks or the Bournemouth sea front (at least Canford Cliffs) but the effect might be small or negligable.

There is no doubt that land level changes can occur above an oilfield. Satellite data has shown that the land has been recently rising to a very small extent, perhaps trivial, in the vicinity of the Wytch Farm oilfield, and that Brownsea Island is very slightly tilting. This, although unremarkable, does not seem be published but it might be. I do not have details, now. The question is probably not whether extraction from a huge oil and gas field will affect the surface; it probably will, but this might be insignificant, just something trivial that will be unnoticed.

With regard to the Bournemouth area, since the very latest maps from oil exploration are not available, it is not clear which parts just could be affected apart, as mentioned, from the obvious places of Sandbanks, Brownsea Island and Canford Cliffs. These places are known to be above oilfields in parts. It is not known whether anything is proved with regard to central Bournemouth. In 2015, however, licence blocks covering much of the western part of Bournemouth were realised (this does not mean that anything is necessarily going to happen), and theoretically the Wytch Farm Oilfield might expand into areas there, but, of course, it might not. A consideration that needs study is the distribution of deep faults under the Bournemouth area. The main faulting is Late Cimmerian [simplified, in plain language - Aptian, Lower Greensand age]. The Late Cimmerian faults are not present at the surface where there is Eocene strata as Bournemouth (they are deeply buried here, but can be seen at Swanage and Kimmeridge etc.). A few may be shown in oil industry maps.

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An enlarged map of new, 2015, oil and gas exploration blocks in the Bournemouth and Isle of Wight area, redrawn completely after a part only of an Oil and Gas Authority map online

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A redrawn map of onshore licence areas for petroleum exploration, including 2015 locations, based on part of a government 2015 licence map, not highly accurate, only approximate

A redrawn map of offshore licence blocks in the Wytch Farm, Bournemouth and Isle of Wight region, to show areas of potential interest, but mainly based on 2014 data

A simplified overview of Wessex Basin structures, oil and gas fields and boreholes

A map showing the oilfields, gas fields and oil kitchens of the Wessex Basin and the western part to the Weald Basin, southern England, Dorset

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See BBC (2015). "New Licences for UK shale gas exploration". The Oil and Gas Authority has awarded a raft of new licences to explore for oil and gas on the mainland of the UK. A new scheme of 2015 sets up a licence area for exploration in the western part of Bournemouth region, but it is not known why this area has been released. This is shown on the rough map above but the boundaries are only approximate.

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8.1 LANDSLIDES AND CLIFF FALLS - East Cliff - 2014 [Introduction]

Bournemouth Pier to Boscombe Pier

CLIFF FALLS - Introduction

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Foreword: Prediction of cliff falls at Bournemouth East Cliff Lift by Dr William T. Ord, F.G.S. in 1914.
[In A Natural History of Bournemouth and District. Edited by Sir Daniel Morris. 1914. see pp. 335-336.]

"The friable nature of their material causes the angle of rest to be a considerable one, and it can never be attained, nor will the cliffs cease to fall, until the accumulation of this talus is permitted to remain beneath them. The new Undercliff Drive does not assist this, as all the falls upon it are necessarily removed by manual labour; and until the top of the cliff has receded far beyond its present position, involving the destruction of the Overcliff Drive, it is difficult to see how their further recession can be prevented. Planting the more shelving of the face with various shrubs has done something to preserve them in places, and may assist in the future, but in the position between the East Lift and Boscombe Pier there can be little doubt that the Municipal Authorities have considerable difficulies before them."

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The coast just east of Bournemouth Pier, Dorset, seen from a helicopter, and showing the location of cliff falls in a specific area, near the estern Cliff Lift, photograph: July 2013

Cliff falls seem to take place every few years in the vicinity of the East Cliff Lift. This is a fairly high part of the cliff, and, in particular, it has a fairly-steep cliff profiles. Several cliff falls have occurred in this area; a major one damaged the cliff lift and destroyed a building at the foot of the cliff in April 2016. Fortunatley it happened at night. There have been others in this area. Some brief description of them is given below.

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Problems and Historic Points
In 1914 (A Natural History of Bournemouth and District, p. 70), it was noted that the cliffs have recently become more vertical. Long ago the slope was relatively gentle. In about 1864, for example, a lady on horseback rode up the cliff between the Zigzag (east of Bournemouth Pier) and Boscombe. This would not be feasible now. In 1914 the natural coastal recession between Bournemouth and Boscombe was between 12 inches [30cm] to 18 inches [46cm - i.e. almost half a metre] a year. This ceased completely with the construction of the promenade in 1914. It effectively fossilised the cliff, and in doing so it retained a particularly steep part near the East Cliff lift. There has been no major erosion, but there has been, over the years, a progresive increase in cliff vegetation, now largely obscuring the near-horizontal, strata of the cliff. However, this vegetation is mostly of a superficial cover of low plants, not trees, and it probably does not have any major effect on stability.

Springs do not seem to be a major factor in the area of cliff falls from the East Cliff Zigzag path to the Cliff Lift and just beyond. The strata are of Pleistocene Gravel (with extremely high porosity and permeability), overlying Boscombe Sand Formation in the upper part of the cliff. This Eocene unit is very porous and permeable. There is some discontinuous, carbonaceous clay at the junction with the main unit in the lower part of the cliff, the Branksome Sand Formation. In places, a perched water table may be theoretically possible. It is very unlikely that any major water body is retained above the carbonaceous clay. A small amount may be held, but extensive open cliff means that water can flow out freely.

In the 1980s there seems to have been some problem of stability at the East Cliff Lift. There had formerly been on the east side at the top, a structure of limestone blocks and terraces, similar to that on the west side at the top. This is shown in an old photograph from 1920s, reproduced here. In the early 1980s it would seem that this upper, eastern part of the cliff adjacent to cliff lift became unstable. Steel gabions (network boxes) containing limestone debris were place here instead. The gabions stayed in place until the April 2016 cliff collapse. Then the block of them rotated and slid away from the cliff top. You can see this in the photographs.

[end of historic notes]

After the Cliff Fall (2014)

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Two landslide sites in the Tertiary sandstone cliffs of Bournemouth, Dorset, as seen to the northeast of  Bournemouth Pier, photograph 8th March 2014

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Two landslide sites in the Boscombe Sand Formation above the Branksome Sand Formation, Bournemouth, Dorset

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A vertical view of the small, steep landslide site  where Boscombe Sand material fell over Branksome Sand Formation, east of Bournemouth Pier, Dorset, photograph 8th March 2014

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Go to Google Earth - "Bournemouth" - to find the location on an aerial photograph.

[LOCATION IMAGE - GOOGLE EARTH AERIAL PHOTO OFFLINE:
C:\USERS\Desktop\Ian\MY PICTURES-MAIN/AA-JPG-NEW-2014-Comp/JPG-BOURNEMOUTH-OFFLINE/14BMT-A-OFFLINE-Bournemouth-Landslide-Site-GE.jpg]

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[2014 Landslide - additional notes - Sturzstrom]

As can be seen here, this 2014 landslide had a steep, concave slip-plane, that was relatively shallow in relation to the previous cliff surface. The slipping was mostly in the Boscombe Sand Formation, which is higher in the cliff, and overlies part of the Branksome Sand Formation. The Pleistocene Plateau Gravel was only involved to a limited extent. Thus the fallen debris was mostly sand and sandy clay of a grey colour. A certain amount of vegetation such as gorse bushes fell with the stratal debris. Because the cliff is about 35 metres in height and most of the fall was from above 10 metres above the promenade and road, the debris fell fast. There was no obstruction. This is why at road level it showed sturzstrom-like features and moved seaward at high velocity and with a turbulent cloud of suspended material. Apparently at the time, near midnight no-one was in the danger zone. If the fall had happened in daytime there would have been risk of at least serious injury to anyone who was unfortunate enough to be in its (limited) path. Most walkers, though, would have been on the beach side of the road. There would not have been any warning of the fall.

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The cliff section of Eocene strata at Bournemouth Pier and a short distance to the East

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There was a relatively small but very fast, sandstone (weak sandstone or sand) fall from the Bournemouth cliffs at night in early 2014. A 20-metre wide strip of poorly-cemented, sand cliff face fell onto the promenade and beach access road at around midnight on the 20th to 21st February 2014. The upper part of the cliff consists of Boscombe Sands Formation (Bartonian age), the lower part Branksome Sand Formation (Bracklesham Group), with Pleistocene gravel of Gravel Terrace 10 of the British Geological Survey above. The cliff here is about 35 metres in height.

Towards the top of the cliff, in the Branksome Sand Formation there is some ferruginous sandstone. This iron-cemented sand is more resistant and which probably is the cause of part of the upper cliff projecting to some extent at this locality. The band of ferruginous sandstone here is probably that shown in a photograph (Plate 14, opposite p. 316) of Ord (1914).

An usual aspect of the small landslide at the Bournemouth cliffs was a fast run-out (a tongue of debris) onto the promenade. Sand debris, some of it in turbulent, cloudy suspension, seemed to travel at fairly high velocity across the promenade to the beach. This was seen in a film of the event from a CCTV camera of the council, and shown in part on television. It showed that at the bottom of the landslide there some characteristics resembling those of a very small-scale "sturzstrom". This is a type of landslide, with a run-out at the base, with particles held in suspension, largely in air, by particle-to-particle impacts. The material flows outward horizontally at the base like a cloud of debris.

[For more this topic see:
Williams, R.B.G. et al. 2004. A Strurzstrom-like cliff fall on the Chalk coast of Sussex, UK. Pp 89-97 in Mortimore, R.N. and Duperret, A. (Eds.), 2004. Coastal Chalk Cliff Instability. Geological Society of London, Engineering Geology Special Publications, No. 20.]

There were bushes and vegetable debris present in the Bournemouth cliff run-out. The rapidity of the fall and the run-out are also reminiscent of the dangerous falls of sandstone cliff at Burton Cliff, Burton Bradstock, Dorset. They, however, are in vertical cliffs, with hard rock and are very dangerous.

An avalanche type landslide, i.e. one with long run-out, has been reported previously from the Bournemouth Cliffs. Gardner (1879) discussed the notable, but now destroyed (by development), Honeycomb Chine, a short distance east of Boscombe Pier. It was at a place where there are now flats, and not far from the new "surf reef". The chine was notable not only for its scenery but also for the occurrence there of fruits of Nipa, the Vietnam Swamp Palm. These are Gardner's comments:

"120 yards beyond this are the Honeycomb Chines, the sides of which are upward of 100 feet high and of most picturesque occurrence. The ridge separating them, deprived of its gravel capping, and formed of snow-white sand [Boscombe Sand Formation], looks quite Alpine with its sharply cut peaks and water-worn gullies, which may be magnified by imagination into chasms and crevasses. The ribbon-like and netted surface, produced by weathering, produces a singular and striking effect. Lyell represented 3 chines at about the same spot; but it is hardly conceivable that any trace of those should remain at this day, as over fifty years have elapsed. Last spring the face of the buttress separating the two fell away like an avalanche, which will take many a rough sea to remove."

An avalanche-like run-out is characteristic of sturzstrom-type rock falls. The comment about sea erosion, indicates that this run-out was substantial. In the past, before the sea wall and promenade was built, and when coast was rapid here, it is quite likely sturstrom-type sand falls might have been common.

The recent small landslide is probably minute in comparison to the Honeycomb Chine fall. It is just a small part of the natural process of degradation of cliffs at Bournemouth and a progressive and slow reduction in slope to an angle of repose. There is not much sandstone and clay exposed now, and the former cliffs are mostly degraded into slopes covered in vegetation. In geological terms the cliff fall has only very slightly increased the amount of exposure of the bedrock. The cliffs are steeper here between the Zizag Path and the Cliff Lift.

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Remains of an older landslide, just to the west of the fall of early 2014; here cement-filled sandbags have been used to try to support the cliff, East Cliff, Bournemouth, Dorset, 8th March 2014

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There are the remains of a previous sand fall a short distance west of the new sandstone fall. The rock wall of Purbeck limestone seems to have been broken through to some extent in a similar landslide. This is shown in a photograph above. Cement-filled sandbags have been used to try to stabilise the lower part of the cliff. Another landslide might occur, sooner or later, between the two existing scars because the cliff is steep and does not have much lateral support now. There is no reason to believe that any cliff fall here would be very large.

For further information see:
Bournemouth Seafront Landslide Caused by Rainfall. News Dorset of the BBC Online. Extract:
Bournemouth seafront manager Chris Saunders is already overseeing the clear-up of 387 beach huts on the borough's coastline, which were damaged or destroyed either by landslips and storms.
He said: "It's not an uncommon occurrence. It's not a huge slip - we've had worse over the years. We had a cliff slip down at Gordon's Corner, at Southbourne, just before Christmas that wasn't quite as big as this but did more damage because it was where some beach huts were. About three or four years ago just the other side of the East Cliff lift we had a substantial cliff slip that went through the back of a building. Knowing we've had the heavy rains, we commissioned a geotechnical expert to come and check the cliffs through but this has slightly beaten us to it."

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8.3 LANDSLIDES AND CLIFF FALLS - East Cliff - 2016 (Major collapse, 25th April 2016)

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Original State of the Cliff (2004)

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An old photograph of 2004, showing the original form of the cliff at the site of the fall of Boscombe Sands on the night of the 20th to 21st February 2014, between the Zizag Path and the Cliff Lift, east of Bournemouth Pier, Dorset

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The cliff location, as seen from the low tide mark in 2004, of the landslide site of 2014, East Cliff, Bournemouth, Dorset

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The cliff location, as seen from the low tide mark in 2004, of the landslide site of 2014, East Cliff, Bournemouth, Dorset, labelled version

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The images above from 2004 are now followed by photographs from 2014 and particularly 2016 to show development of the landslide at the East Cliff Lift, Bournemouth.

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The site of the landslide of April 2016 at the East Cliff Lift, Bournemouth, Dorset, seen seeping water from the cliff, at the critical horizon, in March 2014

The site of the 2016 East Cliff Lift Landslide seen in March 2014 with water seeping out from the base of the future landslide site, Bournemouth, Dorset

The site of the future 2016 landslide was examined to some extent by the writer in March 2014, when considering the general landslide situation in the area. Water was seen to be seeping out from near the boundary of the Branksome Sand Formation (a major constituent of the cliff fall) and the underlying grey clays of the Boscombe Sand Formation. In the cliff the spring is conspicuous because of reed-like grasses growing from wet cracks or joins in the limestone terracing. The stones are wet at the site, and similar spring can be seen in the adjacent cliff, a short distance further east (and are shown in other photographs here).

Thus the spring and the weakness could be easily recognised, but there was no indication in advance that the cliff would fall adjacent to the cliff lift. However, the conditions favoured it, and the water seepage could be seen by anyone. It was not obvious in advance to the casual observer that the cliff would fall at the particular spring line. People, however, with a special interest in the cliff or the cliff-lift might have been more likely to recognise a potential hazard. Fortunately, no-one was injured and the landslide may be to the public just a trivial matter of passing interest. To owners of the cliff and the cliff lift it might be a matter of more significance, especially since other similar landslides might, perhaps, occur sooner or later.

A simple, cross-sectional diagram, not true to scale, showing the general features of landslide at the East Cliff Lift, Bournemouth, Dorset, in April 2016

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Seepage was taking place from the base of the Boscombe Sands, (probably Bartonian) just above the impermeable clays at the top of the Branksome Sand Formation, in March 2014. There was, in effect, a warning there but its significance at the time was not appreciated. Instead, improvement work continued on the cafe building in front. About two years later, in April 2016, the cliff seems to have failed at this wet and weak horizon. Photographs taken shortly after the fall (Yahoo and others) show water running out of the debris at the site of the smashed toilet, running across the road and draing away eastward. It then emerged onto the sand through a drainage pipe under the Undercliff Drive road. It cannot be confirmed for certain that this water was coming from the landslide rather than any broken pipe associated with the toilet facilities. However, examination of the photographs show that some was emerging from a location slightly further west and not apparently connected to the toilet facilities. It is not fully confirmed that the landslide was initiated by water collecting above the impermeable horizon (T4 of Plint) but this seems very likely. The quantity of water may not have been great.

Photographs below show the collapsed cliff, with debris mostly of Branksome Sand. There may have been some limited run-out of debris onto the road when the fall happened. Photographs though taken soon after the incident do not show any major accumulation of debris on the beach. It almost all seems to be on the landward side of the road. Some debris has since been cleared away. Removal of material from the cliff could result in further collapse but the water problem may decrease as dryer summer weather takes place (assuming that it does). The following photographs show some details of the collapsed cliff.

(the following photographs are mainly from the 5th May 2016, after road and beach debris has been removed. The cliff situation has not been altered at this stage.)

The cliff at the East Cliff Cliff Lift, Bournemouth, Dorset, seen on the 5th May 2016, a week and a half after a major landslide here

The East Cliff, Cliff Lift, Bournemouth, Dorset, in about 1920 and after the landslide of April 2016

A closer view of the landslide adjacent to the East Cliff Cliff Lift, Bournemouth, Dorset, as seen on the 5th May 2016

A small hut, apparently a toilet, destroyed by the April 2016 landslide at East Cliff Lift, Bournemouth, Dorset

Cliff lifts pushed together by the landslide of the 25th April 2016, East Cliff, Bournemouth, Dorset

The top part of the landslide at the Cliff Lift, East Cliff, Bournemouth, Dorset, showing gabions at risk of adding weight to the upper slope

The western side of the East Cliff, Cliff Lift, Bournemouth as seen in 2014 before the major landslide here in 2016, note the water seepage from near the base of the Boscombe Sand Formation

The top of the East Cliff Lift Landslide, Bournemouth, seen from the Overcliff Drive, May 2016

A surprising aspect of the major landslide at the Cliff Lift, East Cliff, Bournemouth is that gabions [wire mesh filled with rocks] have been added in the past as some sort of repair measure near the cliff top. See the photographs above. This is surprising. Adding extra weight to the top part of a cliff with a landslide or threat of a landslide is not something that would be expected. It gives additional top weight to the landslide and may increase the tendency of the cliff to fall, or increase the extent of failure.

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[See also the Bournemouth Daily Echo for a good photographic record.]

Pictures: Toilets, cliff path and steps destroyed in East Cliff collapse close to John Egging Memorial.

Tonnes of rock and rubble plunged 100ft onto Bournemouth promenade after a large section of East Cliff collapsed at the weekend (25th April 2016). Officials say it was lucky no-one was seriously injured in the 5am landslip which happened just yards from the Jon Egging Memorial. The clifftop pathway and steps near the memorial were ripped apart in the incident on Sunday, and tonnes of boulders and material obliterated a cafe toilet block at the base of the cliffs. The East Cliff lift was also damaged, with one of its cars knocked off its rails by the force of the impact. Bournemouth Council experts have warned of further landslips over the next 48 hours. Luckily, rangers had spotted signs of the cliff fall hours before it happened, so they were able to cordon off the area as a precaution.
Crowds of people, many of them holidaymakers who had been on the pathway hours before it collapsed, gathered at the site today. "I was actually walking around the Red Arrows memorial yesterday, then a couple of hours later we noticed it had been cordoned off," said Alan Sanders. "Now the pathway has gone. Incredible." Meanwhile, tourist Derek Baker told the Echo: "Yesterday morning I walked down the steps which are no longer there. "It is frightening to think I was only walking along the cliff top at this exact spot yesterday." ]

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The photograph above shows the general scene at the East Cliff Lift, Bournemouth, about a week and a half after a major landslide. Debris has been cleared from the road at this stage, but the collapsed cliff has not been significantly disturbed by artificial action. It can be seen that the debris has fallen from the upper part of the cliff. The strata involved are of the Boscombe Sand Formation (Eocene, probably early Bartonian in age). The lower part of the cliff does not seem to have moved significantly, but it has not been examined because it is fenced off and not accessible.

Notice that at the top of the cliff there is a clean vertical surface broken away from the dark brown Pleistocene Plateau Gravel. It closely resembles the vertical shear planes at the landward side of curved rotational landslides at Barton-on-Sea (in related strata). The debris, seen from the outside of the barrier is mainly of sandstone from the upper part of the cliff, and it is mostly poorly lithified (only just firm, not hard rock). There are some large blocks, though, of harder, cemented sandstone. One of these has landed on the top of the cafe at the foot of the cliff. It is obvious that the Branksome Sand Formation in the cliff here has collapsed. The lower part of the cliff, of Boscombe Sand Formation, does not seem to have collapsed significantly, although it is difficult to be certain from outside the barrier.

Whe the sand and sandstone fell in night of the 4 to the 5th May, there was a major "run-out" across the promenade and onto the beach. This has been filmed on CCTV.

On CCTV - Moment landslide blocks Bournemouth road.

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A near-vertical joint with plant roots that was exposed, probably at the same time as the 2016 East Cliff Lift Landslide, Bournemouth, Dorset, this is just to the east of the main cliff-fall

With fresh debris seen at the same time as the East Cliff Lift Landslide was newly exposed, this joint-like surface seems to be a related feature. It is in top Branksome Sands strata (with penecontemporaneous deformation) that form the lower part of the main landslide, a very short distance further west, along the Undercliff Drive. Other vertical joints were not seen in the area (although they could be present and obscured under debris in the main landslide. The little features shown above seems to be a small part of the cliff which fell at the same time as the Cliff Lift Landslide and has some relationship to it. It is not known, however, as to whether near-vertical joints were involved in the main landslide.

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8.4 LANDSLIDES AND CLIFF FALLS - East Cliff - 2016 - Advance Indications - Evidence

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The slip plane that is at the base of the 2016 East Cliff Lift Landslide was seen in 2014, and this is a general view in that year

Water seepage near the perched water table above the clay unit, just underneath the Boscombe Sand Formation at the East Cliff Lift, as seen, fairly close, in 2014

The slip plane that was to be the cause of the East Cliff Lift landslide in 2016 was already in existence before. It hadd showed some minor movement in March 2014. It is not known whether the coastal engineers were aware of the potential problem here. A steel marker pole seems to have been placed on top of the critical slip plane, but its presence might have been either the result of investigations in progress or irrelevant debris. It would seem quite likely that the potential slip plane would have been studied because of landslide risk.

A closer look at this, from many photographs taken in 2014 is that a clay bed within the top of the Branksome Sand Formation (high Bracklesham - top is Plint's T4) has within a failure or slip surface. This is nearly horizontal. There had been just some very small movement in 2014, but in 2016 there was major failure. Further studies are needed, including an investigation of the clay mineralogy of the clay. There have been limited clay mineral studies by Gilkes (1968) Gilkes (1968) have shown negligible smectite ("montmorillonite" in old terminology). This is compatible with the later report of Hughes and Knox (2006) who referred to the general absence of smectite in the Bournemouth cliffs.

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An aquiclude at T4, top of Branksome Sand Formation, above beach huts, East Cliff, Bournemouth, Dorset

Another possible landslide area is near these huts. The height of the cliff is not great. However there is a relic of a former landslide here. The vegetation has been cleared from this, presumably to check on its safety (it looks quite old).

Obviously the major risk is of being hit by directly falling rocks and debris. In addition, and it happened in this case at Bournmouth, there can be a "run-out". Landslide debris moves rapidly seaward in a clowd of rocks and dust. A runout occurred with this Cliff Lift Landslide. It also happened with the last landslide nearby in 2014 and fortunately no-one was injured. Landslide run-outs of debris are very dangerous.

At Bournemouth cliff falls are fairly infrequent, but they do seem to be happening now about every two or three years or so. Unfortunately, the large number of people present at the foot of the Bournemouth cliffs (at least in daytime) does effectively increase the risk of injury or worse. It is very fortunate that the cliffs at Bournemouth do not fall more often.

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Beach Width and the East Cliff Lift Cliff Fall

The beach width in 2016 at Bournemouth East Cliff has not been measured by the writer. However, I have known this area since the end of Second World War, and I have never seen such a wide and high beach. It is quite abnormal now.

The reader should go to:

Britain from Above - Website.
Britain from Above - East Cliff Lift, an aerial photograph from 1920. There are other good aerial photographs from the past of the Bournemouth Cliffs in this very useful website.

The important point is that the beach was actually narrower at high tide in 1920 than the width of the Promenade or Undercliff Drive here. So therefore conditions were far more favourable for a rotational landslide here back in 1920. However, it did not happen. Instead a landslide with a base, apparently at or above promenade level has occurred recently. The details are not known.

In perspective, it is strange that a significant cliff fall should occur 112 years after the promenade had been built, and, although there have been a few falls in the area, nothing so major that it destroyed the cliff-lift had happened previously. The cliff lift was built in 1908 and it has had some minor falling-away in recent years near the top on the east side, but nothing major. As mentioned there is a spring in the cliff, but that has been there all the life of the cliff lift.

The beach is extremely wide and high now as a result of beach replenishment. When I saw it shortly after the cliff fall in 2016 it was wider than I have ever seen it. In other words, the possible toe of a landslide is extremely heavy and strongly built up. The conditions for a cliff fall in terms of the topography and geomorphology are extremely unfavourable in 2016 but were much more likely to cause a cliff fall in 1920. Is unusual weather the different factor, or is there some other reason for the cliff next to a long-established cliff lift to fall? The old aerial photograph draws attention to the puzzle!

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8.5 LANDSLIDES AND CLIFF FALLS - Other [for future use]

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[Ready for future content. Empty at present, June 2016]

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9.1 ACKNOWLEDGEMENTS

I am very much obliged to Southampton University for running this website from their server. I very much appreciate family help with background assistance indirectly benefitting this particular webpage. I come from Bournemouth and have received family help with the coast of this area since the 1940s (it was difficult to visit the beach then; with much barbed wire and anti-tank defences only certain parts were accessible; there was access to short stretches adjacent to the then broken, Bournemouth Pier. Low-flying German planes dropping bombs on Bournemouth only stopped one family outing; it was close, the pilot could be seen.). More recently, Tonya and Joanna are particularly thanked for arranging a helicopter photographic trip and this has been very helpful. Field trips with students on this stretch of coast have been very helpful. I particularly thank Maurice Sunkin for much helpful information on the East Cliff region.

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[all placed in sections - no epsilon, now, complete but needs text smoothing]

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LINKS: Relevant Websites

Coastal Protection Works at Sandbanks - Borough of Poole. Extracts: "At the beginning of the century, the Sandbanks Peninsula area consisted entirely of sand dunes apart from two coastguard cottages built in 1850 and a few wooden holiday homes. Sandbanks was part of the Wimborne Estates and during the 1910's, the first plots were sold off and a few permanent homes were built. In post war times, the building of luxury residence with their own waterfront and slipway has escalated with the final infilling of smaller houses, bungalows and blocks of flats. Less than half the dwellings are used throughout the year as permanent residences, the rest are used as holiday flats and second homes. In 1929, the whole of the beach and present recreation ground consisting of 13 acres were purchased from the Estate for the sum of 13 pounds." .. "Recent Coastal Protection Work. Phase 1. Due to the increase in the erosion rate and the perceived threat to properties, specialist consultant HR Wallingford was commissioned to produce a design for a coastal protection scheme to deal with the rapidly worsening situation. The scheme chosen built on the partial success of the Midway Path groyne and consisted of four addition rock groynes, one to the west of Midway Path and three to the east. [continues]. [This website is recommended. In case of any difficulty in obtaining it go to the Borough of Poole main website and use the search box. ]

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9.2 REFERENCES

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References and Select Bibliography

See also Bibliography of the Geology of Hengistbury Head webpage.

See also Bibliography of the Geology of Barton-on-Sea and Highcliffe.


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Bamroongrugsa , N. and Kwanjareon, K. 1998. Effects of water salinity on growth of nipa palm seedlings. Internet site: http://wwwclib.psu.ac.th/acad_41/bnop1.htm. Abstract: The experiment was conducted to study the effects of water salinity on growth of nipa palm seedlings (Nypa fruticans Wurmb.) Nipa is a plant highly valued by the villagers of coastal areas. It is found in river estuaries, tidal lands near the sea and on the soft muddy banks of small water ways. Products were obtained from leaves, fruits and sugary sap from fruit or flower stalks. The study was carried out by arranging in groups of young and older seedling. Three levels of salinity were provided for watering the seedlings namely : the fresh water (0 ppt), the brackish water (18 ppt) and the salty water (35 ppt). The results showed that nipa seedlings required fresh water for good growth. The brackish water of 18 ppt caused less growth, while watering with the salty water of 35 ppt resulted in stunted growth and leaf wilting. It was also found that older seedlings appeared to tolerate more to salty water than the younger ones. The results implied that under the natural habitat, different levels of water salinity could control growth and establishment of nipa seedlings.
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BBC. 2015. New licences for UK shale gas exploration. BBC online, 17th December 2015. The Oil and Gas Authority has awarded a raft of new licences to explore for oil and gas on the mainland of the UK. The 93 licences to explore 159 blocks of land could pave the way fro more controversial hydraulic fracturing... Large parts of North East and North West of England have been opened up for exploration. There are also licence blocks in the Midlands, the South of England and Wales. About 75 percent of the exploration licences relate to shale oil and gas. The Oil and Gas Authority6 said a total of 95 applications for licences were received from 47 companies, covering 295 Ordnance Survey Blocks. Among the biggest winners were Ineos, with 21 licences, Cuadrilla, IGas and Southwestern Energy. Ineos said it was "committed to full consultation with all local homeowners, landowners and communities close to its shale gas wells".... [continues]
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Bray , M.J. and Carter, D.J. 1996. Poole Bay and Hengistbury Head. In: Allison, R. (ed) Landforms of East Dorset. Geologists' Association Guide, Geologists' Association, London.
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Bristow , C.R. and Freshney, E.C. 1986. Geology of the Poole - Bournemouth Area. Geological Report for DOE: Land Use Planning. British Geological Survey, Exeter.

Bristow, C.R., Freshney, E.C. and Penn, I.E. 1991. Geology of the Country Around Bournemouth. Memoir for 1:50,000 geological sheet 329 (England and Wales). London, Her Majesty's Stationery Office. 116 pp. ISBN 0-11-884377-X. British Geological Survey. Natural Environment Research Council. (This is the key modern publication to the geology of the Bournemouth area. It is a large paperback, probably still in print and originally sold at 24.75p. It is likely to be available in good local libraries. It is intended for use with the Geological Survey map 329. The emphasis of the publication is on outcrops, lithology and sediments with palaeontological topics covered briefly. It is useful in containing a bibliography of more than 100 references, many of which are not repeated here.)


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Bristow , C.R. and Freshney, E.C. 1986. Geology of the Poole - Bournemouth Area. Geological Report for DOE: Land Use Planning. British Geological Survey, Exeter.

Bristow, C.R., Freshney, E.C. and Penn, I.E. 1991. Geology of the Country Around Bournemouth. Memoir for 1:50,000 geological sheet 329 (England and Wales). London, Her Majesty's Stationery Office. 116 pp. ISBN 0-11-884377-X. British Geological Survey. Natural Environment Research Council. (This is the key modern publication to the geology of the Bournemouth area. It is a large paperback, probably still in print and originally sold at 24.75p. It is likely to be available in good local libraries. It is intended for use with the Geological Survey map 329. The emphasis of the publication is on outcrops, lithology and sediments with palaeontological topics covered briefly. It is useful in containing a bibliography of more than 100 references, many of which are not repeated here.)

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Brownen , G. 1914. Chalybeate spas of Bournemouth cliffs. Proceedings of the Bournemouth Natural Science Society, vol. 5.
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Burnett , D. 1982. Dorset Before the Camera, 1539-1855. Dovecote Press, Stanbridge, Wimborne, Dorset. 134 illustrations. ISBN 0 9503518 7 3. By David Burnett.
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Bury, H. 1916. The physical geography of Bournemouth. Geological Magazine, 53, 133-134. By Henry Bury.

Bury, H. 1920a. Chines and cliffs of Bournemouth. Geological Magazine, 57, 71-76.

Bury, H. 1920b. The chines of Bournemouth. Report of the British Association for the Advancement of Science, Bournemouth, 57, 71-76.

Bury, H. 1925. The Bournemouth plateau and its palaeoliths. Proceedings of the Bournemouth Natural Science Society 16, 72-81.

Bury, H. 1933. The Plateau Gravels of the Bournemouth area. Proceedings of the Geologists' Association, 44, 314-335.

Bury, H. 1934. The Geology of Bournemouth and The Isle of Purbeck. pp. 3-8 in: Watson Smith, S. (1934). The Book of Bournemouth; written for the One Hundred and Second Annual Meeting of the British Medical Association held at Bournemouth in July 1934. Published at Bournemouth, 1934. 212 pp., hardcover book.

Bushell, P. 1989. Piers and Paddle Steamers in Camera. Quotes Limited of Buckingham. 79pp. By Pat Bushell. This has, of course, numerous excellent old photographs of paddle steamers; some of these are shown at or near Bournemouth Pier and may show something of the Bournemouth coast (I like the book because I have often travelled on many of the paddle steamers in the 1950s).

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Calkin , J.B. and Green, J.F.N. 1949. Palaeoliths and terraces near Bournemouth. Proceedings of the Prehistoric Society, 15, 21-37.

Calkin, J.B. 1968. Ancient Purbeck: an account of the geology of the Isle of Purbeck and its early inhabitants. The Friary Press, Dorchester, 61pp. With 48 illustrations. Paperback booklet. Price 6 shillings. By J. Bernard Calkin, M.A., F.S.A. [With notes and illustrations regarding dinosaur footprints, fossil leaves, Roman mosaics, Purbeck Marble, Kimmeridge oil shale objects etc.]

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Carus-Wilson, C.A. 1920. The Chines and Cliffs of Bournemouth. Geological Magazine, vol. 57, issue 4, April 1920, short note on page 120 only. By Professor Charles Ashley Carus-Wilson, Lecturer and Engineer.
Sir - I believe that Mr Bury [Henry Bury, geomorphologist, member of Bournemouth Natural Science Society] is correct in assuming that I am responsible for the statement regarding the general increase in the steepness of the Bournemouth Cliffs. It was made in a lecture on "The Bournemouth Cliffs" delivered at Bournemouth in the spring of 1912. The matter was discussed at the Geological Society after the reading of Mr Bury's paper on January 27, 1916.
As I have not visited Bournemouth since 1912 I am unable to refer to the appearance of the cliffs at the present time [1920], but in 1912 the alteration of the general angle of face-slope was unmistakable, and, in fact, was noticed by several local observers, and subsequently corroborated by the comparison of numerous photographs taken between 1887, when my systematic observations began, and 1912.
Since the Undercliff Drive was constructed there has been a general lowering of the beach westward, and hence a more rapid removal of cliff talus from the base through marine erosion and transport, while at the same time, there has been no proportionate increase in the rate of atmospheric erosion upon the cliff-face. Hence the general angle of slope is no longer approximately 35 degrees, as was formerly the case. I predicted these changes when giving evidence at the Local Government Board Enquiry held at Bournemouth in 1906, and many years before than in the local papers.
It has always seemed to me that an important factor in determining the width and depth of a chine in the making is the bed of clay, or ferruginous sandstone, so frequently present at varying depths below the surface. A stream cutting its way through the softer sandrock ceases to erode its bed with the same rapidity when reaching a stratum of clay or sandstone below, while the widening of the chine by the atmostpheric agencies continues to progress at the same rate.


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Chapman, R., Editor. [Bournemouth Natural Science Society]. 2009. The Natural History of Bournemouth and the Surrounding Area. Written by Members of the Bournemouth Natural Science Society. 238 pp. With a Foreword by Chris Packham. Designed and produced for the BNSS by Wessex Books, Salisbury. ISBN 978-1-903035-32-0. See Section 2 Geology - pp. 37-58, by Justin Delair. The general geological features of the area are discussed in summarised form, and the subject matter is mostly material that is familiar to geologists who study the region. However, a special note of interest is a short section on page 49 on "Zeuglodon" or Basilosaurus on p. 49. This is of particular interest because the first bones of the primitive "whale" were found in the Barton Clay by the Dent family (these included Villiers Dent, who owned Barton Court now on the cliff edge at Barton-on-Sea) . The first-found bones are present in the splendid Dent Collection of Barton fossils acquired by Bournemouth Natural Science Society in 1912. Further bones of "Basilosaurus" have been found in recent years, both at Barton and in the New Forest.


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Chandler , M.E.J. 1960. Plant remains of the Hengistbury and Barton Beds. Bulletin of the British Museum (Natural History), Geology, 4, 191-238.

Chandler, M.E.J. 1962. The Lower Tertiary Floras of Southern England. 2. Flora of the Pipe-clay Series of Dorset (Lower Bagshot). British Museum (Natural History), London.

Chandler, M.E.J. 1963. The Lower Tertiary Floras of Southern England. 3. Flora of the Bournemouth Beds; the Boscombe and the Highcliff Sands. British Museum (Natural History), London.

Chandler, M.E.J. 1964. The Lower Tertiary Floras of Southern England. 4. A Summary and Survey of Findings in the Light of Recent Botanical Observations. British Museum (Natural History), London.

Chandler, M.E.J. 1978. Supplement to the Lower Tertiary Floras of Southern England, Part 5. 47p. Tertiary Research, Special Paper 4.
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Cochrane, 1970. Poole Bay and Pubeck 300BC -AD1660. Printed by the Friary Press, Longmans Ltd., Dorchester. 9pp. Paperback. By Mr. C. Cochrane of Bournemouth, also the author of: The Lost Roads of Wessex. [This is a good book with much useful detail on the area. It has a short bibliography and some maps, both old and new.]

[Example extract - p.9 - The Borders of Poole Harbour, introductory part.]

"Nowadays, in the 1970s, it would be hard to find a vacant plot of land from the Haven Hotel at Sandbanks, where the car ferry plies its incessant passage to Shell Bay, to Fleets Corner beyond Poole, or inland to Wimborne and Christchurch. Westward there is a slight gap between Lytchett Matravers and Sandford (for the lately vacated Admiralty cordite factory at Holton has not yet been turned over to building), but from Sandford the new housing estates run through to Wareham and Stoborough.

Only there, and thanks to the Purbeck landlords, can be found recognition of the open heath that still surrounds Corfe Castle and isolates Swanage; and that till lately provided the rather dreary, sometimes foreboding, background to the entirety-ninety-odd miles - of Poole Harbour. Till lately. . . the peninsula of Sandbanks, the North Haven as it was known, must include today some of the most expensive residential property in all England. Sixty years ago the whole spit of land was on offer for (could it be?) a thousand pounds. That is the measure of it.
Across the harbour entrance from Sandbanks, at Shell Bay or South Haven as is its proper name, there remains mile upon mile of untouched heath, a potential klondyke at which many a land speculator must have pursed his lips. The privately-owned toll road, built with the car ferry in the 1920s, runs from the point towards Studland. An unambitious building or two provide teas for summer visitors. A few houseboats nestle out of sight in a harbourside creek. The walker can wander some three miles along the broad sandy coastline to Studland; five miles, finding his way from track to track, to Corfe Castle; or eight to nine or more in a determined ankle-testing foray to Wareham. Away from the beaches he will meet little company other than an occasional farm or forestry worker, or naturalist. For this is a country beloved of botanists and birdwatchers whose rather pompous "keep off" signs are more plentiful than pedestrians."


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Cooper , N.J. and Harlow, D.A. 1998. Beach replenishment: implications for sources and longevity from the results of the Bournemouth schemes. Pp. 162-177 in: Hooke, J. 1998. Coastal Defence and Earth Science Conservation. The Geological Society of London, Burlington House, London. 270 pp. ISBN 1-897799-96-9. Abstract: Beach replenishment is an effective shoreline management tool which can restore immediately coast protection and amenity functions of a beach... Issues concerning sediment sources and replenishment schemes longevity need to be addressed as future scheme use proliferates... From analysis of a long-term beach monitoring record in Poole Bay, southern England, it is suggested that a viable trade-off can be made between tight particle size grading control and the presence of retention structures in the design of effective replenishment schemes... The conservation of sediment resources is essential if replenishment is to be a sustainable option in the longer term.
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Cox, B. 1981. Paddling Across the Bay; the story of the Bournemouth, Southampton and Weymouth Paddle Steamers. Well-illustrated booklet. Not geological relevant, except that some pictures contain cliffs shown in the distance. The cliffs shown to the west of Bournemouth Pier in 1936 are almost devoid of vegetation. The book is of general relevance to the history of Bournemouth.
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Curry, D. 1976. The age of the Hengistbury Beds (Eocene) and its significance for the structure of the area around Christchurch, Dorset. Proceedings of the Geologists' Association, 87 (4), 401-407. Useful paper with fauna. Makes Hengistbury Beds equivalent to Lower Barton on limited evidence. He found a fauna of moulds 13m above the pebble bed and between the two ironstone nodule horizons.

Curry, D., Adams, C.G., Boulter, M.C., Dilley, F.C., Eames, F.E., Funnell, B.M., Wellis, M.K. (1978). A correlation of Tertiary rocks in the British Isles. Geological Society of London, Special Report No. 12, 72pp.

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Daley , B. 1972. Some problems concerning the early Tertiary climate of southern Britain.Palaeogeography, Palaeoclimatology, Palaeoecology, 11, 11-32. By Brian Daley, Portsmouth University, Portsmouth, UK. Author's abstract: Some of the problems of interpreting the Early Tertiary climate of southern England are reviewed. The London Clay flora is not thought to represent a true Tropical Rain Forest climate, but a climatic type not represented at the present day. The climate was seasonal, but frostless; rainfall was higher for the latitude than that of today; temperatures were elevated, though not necessarily as high as those in Tropical Rain Forest areas today. Tropical plants lived near low-lying rivers and lakes, where edaphic moisture supplemented rainfall and where higher atmospheric humidity occurred. If the extra-tropical plants from the London Clay were truely contemporaneous with the tropical forms, it is suggested that they grew further away from these bodies of water under less humid conditions, though not in higher altitudes. During the Oligocene, the climate of southern Britain was comparable to Eastern Margin Warm Temperate conditions of the present day. Its occurrence on the western margin of a continent reflects rainfalll distributed throughout the year, and introduced by a second belt of Westerlies or moisture bearing winds from the Tethys. Arid conditions in the Paris Basin, deduced from Oligocene gypsum deposits, could not have existed contemporaneously with such conditions in southern England. Alternating pluvial and dry climatic periods are therefore inferred.

Daley, B. and Crewdson, P. 1987. 'Bournemouth Cliffs'; a revised cliff profile and an account of the present distribution of the exposures. Tertiary Research, vol. 8, no. 4, 127-132.

Daley, B., Edwards, N. and Insole, A.N. 1979. Lithostratigraphical nomenclature of the English Palaeogene succession. Geological Magazine, 116, 65-66.
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De la Harpe , P. and Salter, J.W. 1862. Notes on the Eocene flora of Alum Bay etc. Pp 109-120 in:Bristow, H.W. 1862. The Geology of the Isle of Wight. Memoirs of the Geological Survey of Great Britain and the Museum of Practical Geology, for Sheet No. 10. Her Majesty's Stationery Office, London, published by Longman, Green, Longman, and Roberts. With a list of fossils revised by R. Etheridge. 138pp with Plates.

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Eaton , G.L. 1971. The use of microplankton in resolving stratigraphical problems in the Eocene of the Isle of Wight. Journal of the Geological Society, London, 127, 281-283.
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Edwards , E. 1981. A History of Bournemouth. The Growth of a Victorian Town. 164pp. Phillimore and Co. Ltd., Shopwyke Hall, Chichester, Sussex. ISBN 0-85033-412-8. [Not geological but an interesting history of Bournemouth with good historic photographs.]

Edwards, R. A. and Freshney, E.C. 1986. Lithostratigraphical classification of the Hampshire Basin Palaeogene deposits (Reading Formation to Headon Formation). Tertiary Research, 8 (2), 43-73.

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Gao , S. and Collins, M.B. 1994. Beach Profile Changes and Offshore Sediment Transport Patterns Along the SCOPAC Coast: Phase 1 Technical Report. Report No. SUDO/TEC/94/95/C. Department of Oceanography, University of Southampton.

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[GARDNER]

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Gardner, J.S. 1879a. On the British Eocenes and their deposition. Proceedings of the Geologists' Association, 6, 83-106. [This is a fairly general paper, commenting on the whole of the Eocene succession and not, therefore, of much significance to the modern reader. It has no abstract.]

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Gardner , J.S. 1879b. Description and correlation of the Bournemouth Beds. Part 1. Upper Marine Series. Quarterly Journal of the Geological Society, London, 35, 209-228. By J. Starkie Gardner. (Read February 20, 1878)
Descriptions of the coast-section between Highcliff and Bournemouth, with which the present paper deals, have already appeared in publications of the Society. That by Sir Charles Lyelll in 1826, was written when the strata included in this section were still supposed to belong to the Plastic Clay [Reading Formation] underlying the London Clay. In it the different beds forming Christchurch Head [Hengistbury Head] are carefully distinguished, and their superposition illustrated in a somewhat idealized section. The description of the eight miles of cliff from a mile beyond White Pits [a site of coastal sand dunes above the Pleistocene gravel, about halfway between Southbourne and Hengistbury Head - shown on old maps] to Poole Harbour is, however, dismissed in a very few words:- The "section presented by the cliffs is continued so precisely in the line of bearing of the strata [the dip], that no new beds rise up, and it is unnecessary to describe them in detail... The prevail character of the strata throughout this extent of coast is fine white sand; but yellowish and pinkish beds of sand occur, and thinly laminated clays in great abundance, resembling in appearance many of the light-coloured argillaceous marls of Montmatre near Paris; but in none could I discover any organic remains except vegetable impressions and these are very indistinct." The proofs of origin, whether marine or freshwater, are considered equivocal. The total thickness of the series, nowhere exposed to view is put down as "not less than 150 feet." It is also suggested that the argillaceous strata with shells of Alum Bay "are probably concealed here at some of the interruptions of the section."
The next description of these cliffs is by Professor Prestwich in 1848, written principally with the view of determining "the exact position which they bear with reference to the Barton Clay" (l.c.p.43) ...
[continues, including important notes regarding an exposure of the Hengistbury Head ironstone nodules in clay at the Run and at Mudeford Spit, thereby countering some correlations of the Hengistbury Beds with the Lower Barton Clay as seen at Highcliffe. See p. 211 et seq.].

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Gardner, J.S. 1879c. On the correlation of the Bournemouth Marine Series with the Bracklesham Beds, the Upper and Middle Bagshot Beds of the London Basin, and the Bovey Tracey Beds. Geological Magazine, 6, 148-154.

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Gardner, J.S. 1880. Excursion to the Hampshire Coast. Proceedings of the Geologists' Association, London, vol. 6, no. 7, July, 1880, pp. 316-320. Journal edited by J. Logan Lobley, F.G.S., University College, London. Price 1s, 6d.

This field report is of some interest particularly with regard to the cliffs of Bournemouth, which were then exposing good plant fossils, and also in relation to Hengistbury Head, Barton and eastwards. It has no diagrams but the text is reproduced in full, below:




EXCURSION TO THE HAMPSHIRE COAST.

EASTER MONDAY, MARCH 29TH, 1880 AND FOLLOWING DAY.

Director :J. STARKIE GARDNER, Esq., F.G.S.
(Report by Mr. GARDNER.)

The head-quarters of the Association were fixed at Bournemouth, and Members not arriving until Monday were indebted to Mr. Swain for procuring rooms, etc. A large number arrived during the previous week, and were able to explore the Fresh-water series to the west of Bournemouth, which could not be visited on the Monday or Tuesday. An excavation opened a few days previously by Professor Morris, Dr. Hy. Woodward, Prof. Corfield and Mr. Birch, yielding fine leaves, was visited by Dr. John Evans, Prof. McKenny Hughes, Mr. Warrington Smyth, Prof. Bonney, and many Members of the Association. .

First Day .- The Members and visitors, between 60 and 70 in number, met together at Bournemouth pier and proceeded along the shore towards Boscombe. On the way the Director pointed out the position of the Bournemouth series in the Eocene formation, and the chief geological features of the coast. Far to the west, and close to Poole harbour, could be seen the cliffs which contain a rich dicotyledonous flora, shed apparently from forest trees which clothed the hilly slopes of the right bank of the Eocene river. This flora, or rather series of floras, differ remarkably from those found nearer towards Bournemouth, especially in the hitherto total absence of remains of palm. The central ranges of cliffs are almost unfossiliferous, and from their confused bedding are conjectured to present a transverse section of the silting up of the old river channel. From the pier for nearly a mile, the eastern series of leaf-beds extends, containing the remains of a very much more tropical-looking flora, probably derived from the low-lying shores of the left bank of the river. Among the palms, which are very abundant, such genera as Phoenix, Calamus, Iriartea, Sabal, etc., are conspicuous, and among the ferns, some scarcely differing from such magnificently tropical forms as 0smunda javanica and Chrysodium aureum, Gleichenia dichotoma, Lygodim dichotomum, etc. Beyond these cliffs, skirting the nearly vertical Chalk downs, are the Lower Bagshot Beds, in which the well-known leaf-beds of Alum and Studland Bays are situated, invisible on Monday through the haze, and beneath these the Lower Tertiaries. Only the upper part of the Bournemouth Fresh-water series which are estimated to be 400 ft. thick, was actually passed on Monday. The broken angulated blocks, imbedded in sand, whence come Aroids and a representative of Araucaria Cunninghami, not met with higher in the series, were pointed out. Within a few hundred yards the Freshwater series, with its white clays, sharp quartzose sands, and entire absence of flint, became replaced by the Marine series. Owing to the absence of any slips, and the consequent inaccessibility of most of the beds, few fossils could be obtained, although indistinct leaf impressions of the reticulated fern-fronds, which immediately underlie the marine beds, were seen. The passage of Marine to Fresh-water beds at this point was pointed out. The marine beds are stiff liver-coloured clays, becoming black on exposure to the air, containing casts of several genera of Bryozoa and Crustacea, and greenish sandy clay with casts of Bracklesham molluscs. They are highly charged with lignitic matter, and contain in places very perfect fruits, and much teredo-bored wood. Overlying them are the clean white sands, with flint shingle-beds of the Boscombe series, and above these are thick capping of angular Quaternary gravel. The Eocene shingle beds consist of perfectly rounded flints, showing the existence, at the time they were deposited, of a heavy surf. In many cases the condition of the silex is changed, and appears a soft, chalk-like mass. Pebbles are met with in every stage of the change, whol1y converted, with black flint nucleus, half converted, or merely with a thickened white coat. The process and nature of the change gave rise to much discussion. The party were here met by Dr. Allman, President of the Linnrean Society, and Mr. Pike, owner of the vast china-clay pits near Corfe Castle. Nearing Boscombe, the positions of the various fruit-beds were pointed out, and the curious tubular borings of annelids fil1ed with horizontally-arranged lignitic matter or with fine sand, which, in places riddle the dark clays. At the corner of Boscombe Chine, instances of the denuding power of wind were seen, and in the extraordinary Honeycombe Chines, that of springs in rapidly excavating deep cirques in the soft strata. The zone of Nipadites was well seen, the empty husks floated out to sea, and now filled with sand, being in places crowded together. At another spot fragments of proteaceous or myricaceous leaves were found.

The party then proceeded somewhat rapidly to Hengistbury Head, a distance of about four miles. On the way it became apparent that, as the Fresh-water beds present a transverse section across a vast river-channel, so the Marine beds present a section through a great Eocene beach or sandbank, behind which lay a stagnant lagoon. The shingle in them became larger and larger towards the east, their well-rolled appearance indicating the distance they had travelled. Attention was called to their resemblance to the so-called Upper Bagshots of the London Basin.

The principal features of the Head-land itself were fully described in the "Quarterly Journal of the Geological Society" for May, 1879, p. 213, and tbe divisions were clearly made out. Having skirted it along the shore, the party mounted to the top over the debris is of the old quarries, and after enjoying the magnificent view, quickly made their way through the heather, past the prebistoric double ramparts and ditch, to the ferry over the Stour and Avon, and thence to Christchurch. Mr. George H. Birch, F.R.S., B.A., who bad travelled from London for the purpose, gave, in the failing light, an able and only too brief sketch of the history of the ancient and striking Priory Church. The Members then returned by rail to Bournemouth, and dined together at the Criterion Restaurant.

Second Day (Tuesday.) - The party proceeded by rail to Christchurch, when the fine Norman house attracted attention, and the church was again examined while waiting for conveyances. The different building stones used were pointed out by Mr. Birch, these included Hengistbury ironstone for the foundations, and Bembridge, Binstead, Headon, Portland, Purbeck and Caen limestones for the edifice. The Members then drove to Mudeford, and thence found their way along the base of the cliffs to Highcliff. The new channel recently created by the Stour and Avon for a mile along the base of these cliffs caused much surprise when the rapidity with which it had been formed became known. The thin Nummulite bed, which is considered by the Rev. O. Fisher to divide the Bracldesham and Barton Series, could not be found in the short time at disposal, owing to the cliff under Highcliff Castle having been sloped and drained. The main features of the coast were, however, pointed out, the sequence of the beds from Hengistbury to Highcliff, the Barton Clays and Sands, the Upper Bagshots and Headon Beds of Hordle. During the short halt for lunch, Prof. Morris favoured a number of the party with an eloquent address, in which he clearly pointed out the sequence and chief characteristics of the beds and their correlation with the Eocenes of Europe, and briefly sketched, in eulogistic terms, the work of those whose labours have made it possible to trace the history of their deposition.

Dr. Henry Woodward and Prof. Bonney and the Director, having also made a few remarks, the party dispersed to collect the well-known Barton shells, which usual1y lay exposed in thousands upon the slopes of the cliffs, and notwithstanding the dryness of the weather being unfavourable, many beautiful specimens of the characteristic shells and teeth were obtained. Beyond Chuton Bunny most of the party again came together. Owing, however, to the shingly character of the beach, and time pressing, a large number soon after chose the coast path, and viewed the Hordle part of the series from above. Lord Justice Thesiger, of Hordle House, wrote to express his regret at being unable to join the excursion. During a short halt, when Dr. Foulerton kindly proposed a vote of thauks to the Director, the magnificent panorama which stretched for 50 miles, embracing the Isle of Wight, the Solent and the whole coast to St. Alban's Head, and the Purbeck Hills, was fully appreciated. The Members soon after entered the conveyances provided for them at Milford, and drove to Lymington. The 5.50 train to London took the party to Brockenhurst, where a number left it to return to Bournemouth. The Excursion, was largely attended, and owing to the magnificent weather and the beauty and interest of the country traversed, was keenly enjoyed. [end of report]




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Gardner, J.S., Keeping, H. and Monckton, H.W. 1888. The Upper Eocene, comprising the Barton and Upper Bagshot Formations. Quarterly Journal of the Geological Society, London, 44, 578-635. [For Barton see particularly pp. 580, 583-4, 587-591, 594, 601, 620-633].

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Gardner, J.S. 1882. Description and correlation of the Bournemouth Beds. Part 2. Lower or Freshwater Series. Quarterly Journal of the Geological Society, London, 38, 1-15. By J. Starkie Gardner. February 1982. About two years ago I had the honour of laying before this Society a description of the marine beds of the Middle Bagshot, exposed between Highcliff and Bournemouth. In continuation of my former paper, I now propose completing the description of the Eocene cliffs of this part of Hampshire, as far as Poole Harbour.
These are of freshwater origin, and chiefly interestingon account of the fossil flora obtained from them. This appears to be the most extensive and varied yet brought to light from the Tertiary formations; and its study, even now, promises to modify the views held as to the age of the very many of the similar fossil floras described from other parts of the world. .... To illustrate the relative importance of the flora of Bournemouth, I may mention that there are 19 species of ferns described from it, and that only 10 have been met with in all the other British Eocenes and Oligocenes, including Bovey Tracey, and three of these are also found at Bournemouth....[continues]

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Gilkes , R. 1968. Clay mineral provinces in the Tertiary sediments of the Hampshire Basin. Clay Minerals, 7, 351-361.

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Goldring , R., Polland, J.E. and Taylor, A.M. 1992. Excursion A4. Sedimentology and ichnology of the shallow marine Barton Group (Eocene) at Hengistbury Head and Barton on Sea. Pp 53-65 in: BSRG 1992, Southampton, Field Excursion Guides, 65 p. Department of Oceanography, Southampton University.


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Green , J.F.N. 1945. The history of the Bourne and its valley. Journal?


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Guttridge, R. 2005. Boscombe and Southbourne; Photographic Memories. Francis Frith's Photographic Memories series. 94pp. By Roger Guttridge. Note that on p. 29 there is "The view from the Zigzag Path, 1922." This was taken on the East Cliff, looking towards Bournemouth Pier.

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Halcrow , Sir William and Partners, 1980. Poole and Christchurch Bays Research Project, Phase One Report, 2 Volumes. Report to the Department of the Environment.
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Hinchcliffe , J. & Hinchcliffe, V. 1984. Dive Dorset. Underwater World Publications, Area 4 - Offshore Diving, p. 164-5 (extract seen which starts at earlier page unknown and finishes at a later page). Supposed "fossil trees" at Middle Poole Patch, Bournemouth Rocks and Durley Rocks. A Tertiary age is implied. The "trunks" stand up to 5 feet high above the sea-floor. These have subsequently been examined petrographically, by XRD and SEM (by a student of mine) and are, in fact, pipes of pyrite with central cavities. Comparison has been made with the limonitic pipes of Redend Point, Studland, which might have been oxidised pyrite pipes of similar character. (More information will be provided on this subject later).


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Huggett, J.M. and O'B. Knox. 2006. Clay mineralogy of the Tertiary onshore and offshore strata of the British Isles. Clay Minerals, vol. 41, pp. 5-46. J.M. Huggett, Dept. of Mineralogy, Natural History Museum, London, O'B. Knox, British Geological Survey, Keyworth.
Abstract: Tertiary sediments are of restricted occurrence in the onshore British Isle but occur extensively offshore, attaining thicknesses of approximately 4 km. in the Faroe - Shetland Basin and approximately 3 km. in the North Sea Basin. Clay mineral stratigraphic studies of the North Sea Paleocene to Lower Miocene successions show a dominance of smectite (and smectite-rich illite-smectite) with minor illite, kaolin and chlorite. Abundant smectite in the Paleocene and Eocene reflects alteration of volcanic ash derived from pyroclastic activity associated with the opening of the North Atlantic between Greenland and Europe. However, the persistence of high smectite into the Oligocene and Middle Miocene indicates that smectite-rich soils on adjacent land areas may also have been an important source of detrital clays. An upward change to illite-dominated assemblages in the Middle Miocene reflects higher rates of erosion and detrital clay supply, with a subsequent increase in chlorite reflecting climatic cooling. The persistence of smectite-rich assemblages to depths of greater than 3000 metres in the offshore indicates little burial-related diagenesis within the mudstone succession, possibly as a consequence of over-pressuring. Despite the importance of Paleocene and Eocene sandstones as hydrocarbon reservoirs in the North Sea and Faroe-Shetland basins, there are few published details of the authigenic clays. The principal clay cements in these sandstones are kaolin and chlorite, with only minor illite reported.
The offshore successions proved a valuable background to the interpretation of the more intensively studied, but stratigraphically less complete, onshore Tertiary successions. The most extensive onshore successions occur in the London and Hampshire basins where sediments of Paleocene to earliest Oligocene age are preserved. Here clay assemblages are dominated by illite and smectite with subordinate kaolin and chlorite. The relatively large smectite content of these successions is also attributed to primarily to the alteration of volcanic ash. Associated non-smectitic clays are largely detrital in origin and sourced from the areas to the west, with reworking of laterites and "china clay" deposits developed over Cornish granites. Authigenic clays include glauconite (sensu lato), early diagenetic kaolin that has replaced muscovite (principally in the London Clay Formation of the London Basin)and smectite that has replaced ash. Pedogenesis has extensively modified the assemblages in the Reading Formation and Solent Group. Tertiary sediments are largely missing from onshore northern and western Britain, but clays and sands of Eocene age are locally preserved in small fault-bounded basins. Here, clay assemblages are dominated by kaolin and with minor illite.

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King , M.P. 1974. Beneath Your Feet: The Geology and Scenery of Bournemouth. The Purbeck Press, Swanage. 36pp, paperback booklet. By Michael P. King, B.A., County Borough of Bournemouth Education Committee.
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Kingzett , C. 1884. On a chalybeate water and saline deposit from Southbourne-on-sea. Journal?
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Kirkaldy , J.F. 1967. Fossils in Colour. 223pp. Blandford Press, Dorset. [including leaf remains from Alum Bay]


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Kundu, A., Goswami, B., Eriksson, P.G. and Charaborty, A. 2011. Palaeoseismicity in relation to basin tectonics as revealed by soft-sediment deformation structures of the Lower Triassic Panchet Formation, Raniganj Basin (Damodar Valley), eastern India. Journal of Earth Science Systems, Indian Academy of Science, Vol. 120, No.1, February 2011, pp 167-181. Available online. By Abhik Kundu, Bapi Goswami, Patrick G. Eriksson and Abhijit Chakraborty.
Abstract:
The Raniganj basin in the Damodar valley of eastern India is located within the riftogenic Gondwana Master-Basin. The fluvio-lacustrine deposits of the Lower Triassic Panchet formation of the Damodar valley in the study area preserve various soft-sediment deformation structures such as slump folds, convolute laminae, flame structures, dish and pillar structures, sandstone dykes, pseudonodules and syn-sedimentary faults. Although such soft-sediment deformation structures may be formed by various processes, in the present area the association of these structures, their relation to the adjacent sedimentary rocks and the tectonic and depositional setting of the formation suggests that these structures are seismogenic. Movements along the basin margin and the intra-basinal faults and resultant seismicity with moderate magnitude (2 -5 on Richter scale) are thought to have been responsible for the soft sediment deformation.

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Lavender , J. 1985. Land Shape and Geology. Pp. 9-13 in: Pepin, C. 1985. Hengistbury Head. Bournemouth Local Studies Publications, Roman Press Ltd., Bournemouth, 79pp.
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Lyell , C. 1827. On the strata of the Plastic Clay Formation exhibited in the cliffs between Christchurch Head, Hampshire and Studland Bay, Dorsetshire. Transactions of the Geological Society, London, Ser. 2, 2, 279-286.

Lyell, C. 1871. The Student's Elements of Geology. John Murray, Albemarle Street, London, 624pp. By Sir Charles Lyell, Bart. F.R.S., Author of 'The Principles of Geology', 'The Antiquity of Man' etc. With more than 600 illustrations on wood. (Brief references to Bournemouth on pp. 237, 238).

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Mackley. 2016. (originally 2015) Good Progress on Bournemouth Beach. Webpage with photographs. Mackley: Good Progress on Bournemouth Beach. Web page 2016.
Mackley is making good progress on the first phase of a long-term project to provide enhanced protection to Bournemouth beach. The current works are part of the Bournemouth Beach Management Scheme, a 17-year programme of work planned from 2015 to 2032. The scheme will eventually see all of the existing 53 groynes replaced and an additional three new groynes constructed, along with beach replenishment every five years. The entire project is expected to cost in the region of 50 million pounds, with the majority of funding provided by the Environment Agency and a smaller contribution from Bournemouth Borough Council. The initial phase being carried out by Mackley will see 10 groynes replaced at a cost of 3.6 million pounds. Works commenced in October 2015 and are scheduled for completion in early June 2016 - before the busy summer season.
Steve Martin, Mackley Contracts Manager, said: Progress was slow at the outset due to ground conditions making piling difficult. We overcame the conditions by pre-augering each position and installing piles using the Mackley Movax rig. Planking commenced as soon as first groyne piling was completed. The planks are 17 number deep by 300 mm which requires considerable excavation volumes (see pic below), and all excavations have to be backfilled each day to prevent quicksand forming. To date we have completed all of the piling works and more than 50 percent of the planking. We are working single tides during neap tides and double tides for seven days during spring tides in order to complete works at outer ends. [continues - see webpage and see photographs]
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May , V. 1990. Replenishment of the resort beaches at Bournemouth and Christchurch, England. Journal of Coastal Research, SI (6), 11-15.
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Melville , R.V. and Freshney, E.C. 1982. British Regional Geology: the Hampshire Basin. Institute of Geological Sciences, H.M.S.O., London. (Good introduction to the geology of the region).
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Monckton , H.W. and White, H.J.O. 1910. Hampshire and Bagshot District. Chapter 12, pp. 277-292 in: Monckton, H.W. and Herries, R.S. (Eds.) 1910. Geology in the Field. The Jubilee Volume of the Geologists' Association (1858-1908). Edward Stanford, London. 916 pp. Illustrated by 32 plates and 138 figures in the text. ["The Association has on three occasions visited the cliffs of Bournemouth and Barton, viz., at Easter, 1880, Easter, 1888, and Easter, 1894, and Mr Starkie Gardner, who acted as director, or one of the directors, on these occasions, explained that he did not wholly agree with the classification of strata adopted by the Geological Survey. His views of the relationship of the Hampshire Eocene beds to those of the Isle of Wight are very clearly shown by the diagram ..." continues. It includes fig. 48. View of the cliffs between Poole Harbour and Boscombe, showing position of plant-beds etc., J. Starkie Gardner. In addition to discussion of the Bournemouth cliffs before the promenade was built, and of Hengistbury Head, and of the breaching of Mudeford Spit, there are description of the Barton and Hordle cliff sections.]

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Morris , D. 1912. Nipadites in Eocene beds at Bournemouth. Proceedings of the Bournemouth Natural Science Society, 3, 78-81.

Morris, S. (Steven). 2009 (23rd January 2009). Shifting Sands Swell the Cost of UK's First Artificial Reef. The Guardian Newspaper, Friday 23rd January, 2009.
If all had gone to plan surfers would by now be whizzing into a Bournemouth beach on waves boosted by Britain's first artificial surf reef. Instead, taxpayers face a bill of almost a quarter of a million pounds to stop the project blowing away. The reef at Boscombe, east of the main town of Bournemouth, in Dorset, was due to be completed in the autumn but rain and winds halted the construction. Work is due to resume in April and finish by the summer's end. But the delay has inflated the reef's price and Bournemouth borough council says 169,000 pounds has to be found to replace sand brought in for its construction on the seabed but lost to the elements over the winter [see photographs above]. Flattening the temporary dune to protect it from the wind and tides would cost a further 70,000 pounds, says a report due to be seen by the local authority next week. Besides this, 100,000 pounds is reportedly needed to help pay the contractors, ASR. Originally the price of the reef project was estimated at 1.4m pounds. By last summer it was up to 2.7m pounds and, following the winter delay, it is now at the 3m pound mark. It could also cost as much as 100,000 pound a year to maintain the reef, and the cost of the wider regeneration project for Boscombe has also risen, to 11m pounds. Basil Ratcliffe, a Tory councillor, said: "Someone should be given the bullet over this ... these are big sums that could have been spent on something else." The report defends the soaring price, saying the reef is a complex marine structure. A council spokeswoman said: "The council has set aside ... 169,000 pounds but it might not need to buy this much [sand]."

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Morton, A. 2016. A Collection of Eocene and Oligocene Fossils; compiled by Alan Morton. Go to:
A Collection of Eocene and Oligocene Fossils, compiled by Alan Morton.
This Eocene and Oligocene Web Site of Alan Morton displays more than 2,000 of the characteristic fossils of the Eocene and Oligocene deposits of England. The photographs are of very high quality and very impressive. The main subsections, which can clicked on to enter, are: London Clay, Bracklesham Beds, Barton Beds, Headon Beds, and Hamstead, Osborne and Bembridge Beds. The particular collection that is the source of the specimen or specimens is cited. The author of the species is given, and with the date. The size is given in millimetres. Varieties are specified, with the name of the author. The CONTENTS list includes: THE COLLECTION; Instructions; What's New; Stratigraphy; References; Links; Acknowledgements; Contact Alan Morton. This website has been given the "Golden Trilobite Award" of the Palaeontological Association. It is an extremely useful and quite remarkable website.

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Ord , W.T. 1910. In: Hovenden, F., Monkton, H.W., Ord, W.T. and Woodward, A.S. Excursion to Swanage, Lulworth Cove and Bournemouth. Report by the Directors. Proceedings of the Geologists' Association, 21, 510-521.

Ord, W.T. (Dr William T. Ord) 1914. Geology. Pp. 303-356 in: Morris, D, 1914. (Editor - Sir Daniel Morris, K.C.M.G, J.P., M.A., D.C.L., D.Sc., F.L.S., F.R.H.S., President of the Bournemouth Natural Science Society). A Natural History of Bournemouth and District; including Archaeology, Topography, Municipal Government, Climate, Education, Fauna, Flora and Geology. By the Members of the Bournemouth Natural Science Society. 400pp. Published by the Natural Science Society. Sold by Horace G. Commin, 100, Old Commercial Road and Bright's Stores Ltd., The Arcade, Bournemouth. [This is an interesting account written when much was still visible in the cliffs and with some good points not discussed much elsewhere.]

Ord, T., Rankin, W.M. and St. Barbe, H. 1914. Topography. In Morris, D. 1914. A Natural History of Bournemouth and District. 400pp. By Dr. William T. Ord, F.G.S., William Munn Rankin, M.Sc., B.Sc. and Henry St. Barbe.

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Pepin, C. 1985. Hengistbury Head. Bournemouth Local Studies Publications, Roman Press Ltd., Bournemouth, 79pp.

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Peters, J., Couling D. and Ridley, M. 1978. Bournemouth Then and Now. Blandford Press, Poole, 224pp. Hard Cover, large book. ISBN 0 7137 0871 9. By John Peters, David Couling and Michael Ridley. An important historical publication with hundreds of old black and white (i.e. monochrome) photographs of Bournemouth showing the town, houses, people, piers, espanades and the Bournemouth coast and cliffs, in many different aspects. There are no colour illustrations. It is an impressive, good quality book. The pictures are Moire type of prints, but with very fine grain, fairly large photographs and they are generally good and clear. The book is recommended to geologists who wish to see the various pictures which include Bournemouth and Poole Bay coast in its relatively unspoilt condition before the promenade or espanade was constructed in 1914. The book is available online at prices from a few pounds to about 20 pounds. Try AbeBooks.co.uk.
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[By Dr. A.G. Plint or Dr. Guy Plint, a Professor at Western University, Ontario, Canada. He completed his D.Phil on the Bournemouth Cliffs in 1980 when he was at Oxford University. His papers are the most informative on the sedimentology of the Eocene Bournemouth cliffs.]

Plint , A.G. 1980. Sedimentary Studies in the Middle Eocene of the Hampshire Basin. Unpublished D.Phil. Thesis, University of Oxford, 3 volumes.

Plint, A.G. 1982. Eocene sedimentation and tectonics in the Hamphire Basin. Journal of the Geological Society of London, 139, 249-254.

Plint, A.G. 1983a. Sandy fluvial point-bar sediments from the Eocene of Dorset, England. Special Publication of the International Association of Sedimentologists, No. 6, 355-368.

Plint, A.G. 1983b. Facies, environments and sedimentary cycles in the Middle Eocene, Bracklesham Formation of the Hampshire Basin: evidence for global sea-level changes? Sedimentology, 30, 625-653.
Abstract:
The Bracklesham Formation is of Middle Eocene age and occurs throughout the Hampshire Basin of southern England. The basin is elongated east-west and filled with Lower Tertiary sediments. Its southern margin is marked by either large, northward-facing monoclines, or faults, both of which underwent differential movement, with uplift of the southern side throughout the Middle Eocene. The Bracklesham Formation, which is up to 240 m thick, shows pronounced lateral facies changes with dominantly marine sediments in the east passing to alluvial sediments in the west. Four principal sedimentary environments: marine, lagoonal, estuarine and alluvial are distinguished. Marine sediments comprise six facies including offshore silty clays and glauconitic silty sands, beach and aeolian dune sands, and flint conglomerates formed on pebble beaches. Offshore sediments predominate in the eastern part of the basin, as far west as Alum Bay, where they are replaced by nearshore sediments. Lagoonal sediments comprise four facies and formed in back-barrier lagoons, coastal marshes and, on occasions, were deposited over much of the basin during periods of low salinity and restricted tidal motion. Five estuarine facies represent tidal channels, channel mouth-bars and abandoned channels. These sediments suggest that much of the Bracklesham Formation was deposited under micro- to meso-tidal conditions. Alluvial sediments dominate the formation to the west of Alum Bay. They comprise coarse to fine sands deposited on the point-bars of meandering rivers, interbedded with thick sequences of laminated interchannel mudstones, deposited in marshes, swamps and lakes. Extensive layers of ball clay were periodically deposited in a lake occupying much of the alluvial basin. In alluvial areas, fault movement exposed Mesozoic rocks along the southern margin of the basin, the erosion of which generated fault-scarp alluvial fan gravels. Locally, pisolitic limestone formed in pools fed by springs emerging at the faulted Chalk-Tertiary contact. In marine areas, flint pebbles were eroded from coastal exposures of chalk and accumulated on pebble beaches and in estuaries. From other evidence it is suggested that older Tertiary sediments were also reworked. The Bracklesham Formation is strongly cyclic and was deposited during five marine transgressions, the effects of which can be recognized throughout the basin in both marine and alluvial areas. Each of the five transgressive cycles is a few tens of metres thick and contains little evidence of intervening major regression. The cycles are thought to represent small-scale eustatic sea-level rises ('paracycles') superimposed upon a major transgressive 'cycle' that began at the base of the Bracklesham Formation, following a major regression, and was terminated, at the top of the Barton Formation by another major regression. This major cycle can be recognized world-wide and may reflect a period of rapid northward extension of the mid-Atlantic ridge.

Plint, A.G. 1983c. Liquifaction, fluidization and erosional structures associated with bituminous sands of the Bracklesham Formation (Middle Eocene) of Dorset, England. Sedimentology, 30, 525-535. (Carbonaceous rather than bituminous sands?). Abstract: At Hengistbury Head, Dorset, the Boscombe Sands (Middle Eocene, Bracklesham Formation) are of estuarine channel facies. A mud-filled channel is exposed, the banks and eastern flank of which have a black carbonaceous stain, the degraded remains of a bitumen. At the time of deposition, the bitumen rendered the sediment firm and it was extensively burrowed by a Thalassinoides-forming organism (crustacean). The bituminous sand on the eastern channel bank suffered brecciation and dilation as a result of liquefaction and flowage of the underlying sediments. This is thought to have been due to rapid expulsion of pore water, possibly as a result of seismic shock. The layers of bituminous sand below the surface were ruptured during water-escape, resulting in localized zones of rapid flow causing fluidization and the development of dewatering pipes up to 1.2 m long. The estuarine sediments were subsequently transgressed during which the bituminous sand was exposed on the seafloor, when it was eroded into a hummocky topography and heavily burrowed. Blocks of bituminous sand were reworked into the marine basal conglomerate, composed mainly of flints, demonstrating the remarkable strength of the bituminous cement.
[I have not seen any evidence that this black sand is bituminous. It seems merely carbonaceous. Other people seem to have found it to be carbonaceous. However, I have not made on systematic study and will accept that it is bituminous if clear evidences is given. The liquifaction evidence is important. ]

Plint, A.G. 1988. Sedimentology of the Eocene strata exposed between Poole Harbour and High Cliff, Dorset, UK. Tertiary Research, 10, 107-145.


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Poole and Christchurch Bays, Shoreline Management Plan - SMP - Key Publications

See these important documents on the plans for the coastal management or shoreline management of the area. Summarised contents of a version are given below and look for the section of interest. However, this SMP is not the final version, and there will be an update. If you do not find it directly from the links here, search by Google etc for the latest version, using the keywords - "Poole Christchurch SMP".

Poole and Christchurch Bays Coastal Management Group. 2010. (SMP - Shoreline Management Plan)
Poole and Christchurch Bays Coastal Management Plan (or SMP - Shoreline Management Plan). Draft SMP2. Draft version of the SMP, later to be replaced by final version (see this when it is available. SMP2 is due to be published in April 2010.). Available online as PDFs at Poole and Christchurch Bays Coastal Management Plan.

Contents: Draft SMP2
Section 1, Introduction
Section 2, Environmental Assessment
Section 3, Basis for Development of the Plan
Section 4, Appraisal of Options and Rationale for Preferred Plan:
Section 4.1, Introduction.
Section 4.2, Policy Development Zone 1 Central and Eastern Sections of Christchurch Bay (Hurst Spit to Friars Cliff).
Section 4.3, Policy Development Zone 2 Christchurch Harbour and Central Poole Bay (Friars Cliff to Flag Head Chine).
Section 4.4, Policy Development Zone 3 Poole Harbour and Associated Coastline (Flag Head Chine to Handfast Point, including Poole Harbour).
Section 4.5, Policy Development Zone 4 Swanage (Handfast Point to Durlston Head).
Section 5, Summary of Preferred Plan and Implications
Section 6, Policy Summary, including Policy Summary Map.
Appendices (all documents open in a new window)
Appendix A, SMP Development.
Appendix B, Stakeholder Engagement.
Appendix C, Baseline Process Understanding, including Coastal Process Report and Flood and Erosion Mapping. Accessible from a separate page including No Active Intervention (NAI) and With Present Management (WPM) assessments, and summaries of the data used in assessments.
Appendix D, Natural and Built Environment Baseline (Thematic Review).
Appendix E, Issues and Objective Evaluation.
Appendix F, Strategic Environmental Assessment.
Appendix G, Scenario Testing.
Appendix H, Economic Appraisal.
Appendix I, Estuary Assessment.
Appendix J, Habitat Regulation Assessment - Appropriate Assessment.
Appendix K, The Metadatabase, GIS and Bibliographic Database is provided to the operating authorities on CD. It will be included in the final SMP.
Appendix L, Water Framework Directive (WFD)
Appendix M, Review of Coastal Processes and Associated Risks at Hengistbury Head.

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Prestwich , J. 1846. On the Tertiary or Supracretaceous Formations of the Isle of Wight, etc. Quarterly Journal of the Geological Society, London, 2, 255-259.

Prestwich, J. 1849. On the position and general character of the strata exhibited in the coast section from Christchurch Harbour to Poole Harbour. Quarterly Journal of the Geological Society, London, 5, 43-49.
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Reid , C. 1898. Geology of the Country round Bournemouth. Memoir of the Geological Survey. Sheet 329 (England and Wales). By Clement Reid.

Reid, C. 1916. Ancient rivers of Bournemouth. Proceedings of the Bournemouth Natural Science Society, 7, 73-82.

Reid, C. and Chandler, M.E.J. 1933. The Flora of the London Clay. British Museum, Natural History, London, 561pp.


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Riddle, C. (Charles). 1934. Bournemouth: an Historical Sketch. Pp. 38-47 in Watson Smith (1934). The Book of Bournemouth. 2010 pp.

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Smith , A.G. and Briden, J.C. 1977. Mesozoic and Cenozoic Paleocontinental Maps. Cambridge Earth Science Series, Cambridge University Press, 63 pp. ISBN 0 521 29117 8 (paperback).
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Stinton , F.C. 1975. Fish otoliths from the English Eocene. Palaeontographical Society (Monograph) : (1), pp.1-56. by Fred Stinton.

Stinton, F.C. and Curry, D. 1979. Lithostratigraphical nomenclature of the English Palaeogene succession. Geological Magazine, 116, 66-67.

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Velegrakis , A.F. 1994. Aspects of the Morphology and Sedimentology of a Transgressional Embayment System: Poole and Christchurch Bays, Southern England. Unpublished Ph.D. Thesis, Department of Oceanography, Southampton University, 319pp.

Velegrakis, A.F., Dix, J.K. and Collins, M.B. 1999. Late Quaternary evolution of the upper reaches of the Solent River, southern England, based on marine geophysical evidence. Journal of the Geological Society, London, vol. 156, pp. 73-87. [This is a key paper with a map showing the offshore buried channels in Poole Bay and Christchurch Bay.]
Abstract: Geological evidence suggests that during the Late Quaternary, a river system (the Solent River) drained a large part of central Southern England. Its upper reaches flowed in a west-east direction, flanked to the south by a Chalk ridge (the Purbeck-Isle of Wight Chalk Ridge). Today, only part of the upper reaches of the river's tributary channels remain, as the area was inundated during the Flandrian Transgression, forming. an embayment system (Poole and Christchurch Bays). In order to map the offshore buried channels of the upper reaches of the Solent River an extensive set of shallow-marine geophysical data was analysed and interpreted. The results of this investigation show that the Solent River system was disrupted irreversibly by southerly capture of its upstream section before the Flandrian Transgression. This disruption was the result of the fluvial breaching of the southern barrier of the system (the Purbeck-Isle of Wight Ridge) at three points, probably during Late Devensian time. Poole Bay was first to be submerged during the transgression. The estuaries which resulted from the drowning of the fluvial palaeovalleys of Poole Bay were infilled with transgressive facies sequences which have been preserved within the buried palaeovalleys. In contrast, Christchurch Bay was submerged at a later time, but because of the abrupt manner of its inundation, no transgressive facies have been preserved within its buried palaeovalleys. [end of abstract]
[Example extract from the introduction] The Isle of Wight, southern England, is separated from the mainland by a stretch of water known as the Solent (Fig. I). The Solent is located at the southern margin of the Hampshire Basin, an elongated asymmetrical downwarp of Tertiary deposits, the southern limb of which exhibits a near-vertical northern dip, whilst the beds on its northern limb slope gently southward (Melville & Freshney 1982). It has been widely proposeq that, during Pleistocene lowstands, the Solent formed a segment of a major axial stream (the 'Solent River'), which integrated all the consequent rivers of the basin (Fox 1862; Reid 1905; Everard 1954; West 1980). It has been suggested that this river constituted one of the principal northern tributaries of the English Channel River, a major river system established over northwestern Europe early in the Middle Pleistocene Epoch (Gibbard 1988). The Solent River flowed along a large W-E-trending valley incised into Tertiary arenaceous and argillaceous sediments and surrounded by high Chalk country (the Wiltshire and North Dorset Downs to the north and the South Dorset Downs and the Purbeck-Wight Chalk Ridge to the south). Much of the catchment area of the river was drowned during the last eustatic sea-level rise. Only parts of the tributary river systems are still intact; these form the modern drainage network of the area (Fig. 2).
Evidence for the existence of the Solent River system is distributed throughout the area. Onshore, extensive deposits of Pleistocene sands and gravels occur, forming terraces along the present river valleys (Keen 1980; Freshney et al. 1985; Allen & Gibbard 1993), and underlying the Flandrian deposits of some of the estuaries of the area (Nicholls 1987). Offshore, marine geophysical surveys have revealed systems of buried river valleys under the present seafloor, incised to a maximum depth of 46 m below OD to the east of the Isle of Wight (Hamblin et al. 1992). [continues for more than 14 pages, with maps and diagrams].

Velegrakis, A.F., Dix, J.K. and Collins, M.B. 2000. Late Pleistocene - Holocene evolution of the upstream section of the Solent River, Southern England. Pp. 97-99 in: Collins, M. and Ansell, K. 2000. Solent Science - A Review. Elsevier, Amsterdam, 385pp. [Using shallow seismic and echo-sounder profiles, seven palaeovalleys have been recognised offshore in Poole and Christchurch Bays. In Poole Bay, Palaeovalleys I, II and III appear to cut southward through the Purbeck-Wight ridge. In contrast Palaeovalleys IV, V, VI and VII in Christchurch Bay do not appear to cut through the Ridge. Valley-filling sediment of significant thickness are found only within Palaeovalleys I and II (Incidently Palaeovalley I has recently been intersected by a civil engineering borehole on the Sandbanks Peninsula)]

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Watson Smith, S. (1934). The Book of Bournemouth; written for the One Hundred and Second Annual Meeting of the British Medical Association held at Bournemouth in July 1934. Published at Bournemouth, 1934. 212 pp., hardcover book with illustrations.


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Webster Smith , B. 1931. The World in the Past: A Popular Account of What it was Like and and What it Contained. 2nd Edition. Frederick Warne and Co. Ltd. London. 365pp.
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West , G.H. 1886a. in: Report of the committee ... appointed for the purpose of inquiring into the rate of erosion of the sea coasts of England and Wales, and the influence of the artificial abstraction of shingle or other material in that action. 6 Christchurch to Poole. Topley, W. (editor). Report of the British Association for the Advancement of Science for 1885, 427-428.

West, G.H. 1886b. The geology of Bournemouth. Proceedings of the Dorset Natural History and Archaeological Society, 7, pp ?.
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White , H.J.O. 1917. Geology of the Country around Bournemouth: Explanation of Sheet 329 [Geological Survey 1 inch to one mile sheet for Bournemouth]. By H.J. Osborne White, F.G.S. 2nd Edition. Memoirs of the Geological Survey, England and Wales. Published by order of the Lords Commissioners of His Majesty's Treasury. Printed by J. Truscott and Son, Ltd, under the authority of His Majesty's Stationery Office. 79 pp. [This is an old edition of the Geological Survey Memoir - see also - Bristow, C.R., Freshney, E.C. and Penn, I.E. 1991. Geology of the Country around Bournemouth. Memoir for 1:50,000 geological sheet 329 (England and Wales). British Geological Survey, London, 116p. There is also the first edition of 1898 by C. Reid. Preface to the Second Edition by A. Strahan, Director: "The first edition of this Memoir, which was written by the late Mr. Clement Reid, was exceptionally brief, a general memoir descriptive of the Hampshire Basin as a whole having been at that time in contemplation. Circumstances have prevented the preparation of the larger work, and opportunity has now been taken ot the exhaustion of the stock of the original pamphlet to produce a memoir on the lines of other New Series Sheet Explanations... continues .. Much of the ground has been re-examined by Mr. White in order to bring the memoir up to date, but the map remains unaltered as the edition published in 1895 and colour-printed (Drift) in 1904."]
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Wood, N., 2010. Keeping the Sea at Bay. For over one hundred years, Poole has worked constantly to protect itself from the eroding effects of the waves, as Nick Woods recounts: The Dorset Magazine, Dorset Life. The Best of Dorset in Words and Pictures. Published in August 2010. By Nick Woods.
Go to:
Keeping the Sea at Bay.
'By gradually carrying out the works recommended .. a considerably greater improvement in the condition of the foreshore can be effected ... to achieve this, however, as is indeed essential in all works on the sea coast, great care and constant vigilance are needed...' This was the advice given by Professore L.F. Vernon-Harcourt in 1903 to the Poole Harbour Commissioners regarding erosion at Sandbanks and a proposal to construct an under-cliff drive at Bournemouth. If the narrow neck of land leading to Sandbanks had been breached it would have changed the face and history of Poole, jeopardising the operation of the Harbour and the development of the peninsula, which is now famed for its expensive property and celebrity residents. Seaside postcards from this time already show the developing use of the coast for leisure, the erosion of the cliffs and, in some cases, what seems to be early attempts at coast protection.
Professor Vernon-Harcourt found that the thirteen groynes built at Sandbanks between 1896 and 1898 were already in need of repairs and additions. He was able to make use of sea charts going back to 1785 and the results of 'float experiments' made in 1890 by John Elford, the Borough Surveyor, in connection with the Poole sewage outfall. The Borough's engineers have been working on the beaches and cliffs ever since, but now have the benefits of computer modelling and highly accurate surveying to assist them. The most recent works were the construction of rock groynes at the Borough boundary at Branksome Dene Chine in early 2009. Fifteen such groynes now protect Poole's beaches, along with two earlier timber and rocks groynes subsequently capped with concrete. The remains of earlier groynes are now buried beneath the beach itself.
[this continues with further information on creating dunes, maintaining beach levels, pumping sand by pipeline on a huge scale and altering yellow sandy cliffs into dismal sloping heathland. It is not enjoyable reading for the geologist, but it certainly is a good account. It shows the Bournemouth - Sandbanks coast to be very artificial and although seeming fairly natural, is really a large-scale engineering area, rather like a motorway. This is probably inevitable for a crowded holiday location, but one has to regret the loss of the natural cliffs.]

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Young , J.A. 1989. The Story of Southbourne. Bournemouth Local Studies Publications, The Professional Education Centre, 40 Lowther Road, Bournemouth, BH8 8NR. No. 695. 50pp. [John A. Young went to Bournemouth School and at one time was in the RAF (as did the writer here, Ian West, much later). John Young later became a Chief Adminstrative Officer for local schools. He wrote local history books on Pokesdown, Southbourne and Tuckton in the Bournemouth area.]
The publication on Southbourne is a very informative and well-organised booklet on the area.
Example extracts:
"Southbourne on Sea offers an interesting study of local enterprise, in which a deliberate plan was embarked upon to establish a new health resort, together with an associated residential district, quite separate from the rapidly expanding town of Bournemouth. The founder of this enterprise was Dr. Thomas Armetriding Compton, who had taken up practice in Bournemouth in 1866. ......
In March 1875 Dr. Compton purchased Cellars Farm; the land of the farm was good agricultural ground, a great deal of which was subsequently lost to the sea due to erosion. The higher ground [to the west] of Dr. Compton's property was covered with gorse or was sandy wild. In the north west corner was a small oak wood named Foxholes, and a little to south of this was a small fir plantation. ......
Probably the most noteworthy of the development works of the Land Company was the [Southbourne] Undercliff Esplanade. ..... The promenade consisted of a curved roadway forty feet wide, with a pedestrian pathway sixteen feet wide on the seaward side, the whole extending for about a third of a mile. At the centre of the promenade there was a short circular bend seaward, which might form an entry for a possible future pier. The sea wall rose to about eight feet above beach level, with foundations from six to nine feet below it. .. The whole of the works cost about 15,000 pounds [a very large sum of money then]. ..... The undercliff promenade [at Southbourne] was made many years earlier than the Undercliff Drive at Bournemouth.... six large houses were to be erected on the Drive .... continues with details about the new Southbourne Pier [800 feet long or thereabouts]; decking seventeen feet above high water mark, and thirty feet wide. ... Pier inaugerated on 2nd August 1888 without ceremony. .. Steamer 'Lord Elgin' would provide a daily service between Bournemouth and Southbourne Piers. [Paddle steamer services were suspended because of rough sea conditions]... After Christmas 1900, the closing days of December brought gales, and a storm of exceptional ferocity swept over the country on 28th December. At Southbourne the sea wall was breached and the pier damaged severely; further storms early in January extended this damage... The pier was finally dismantled in 1907." [the Undercliff Parade was abandoned, houses on the Esplanade were demolished and the whole parade gradually distintegrated .. some remains still visible over thirty years later.

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|Home and Contents | |Field Guides - Introduction |Sandbanks Peninsula |Brownsea Island, Poole Harbour |Hengistbury Head |Highcliffe, Barton & Hordle Geology |Studland, South Haven Peninsula |Sandbanks Peninsula

Copyright © 2016 Ian West, Catherine West, Tonya Loades and Joanna Bentley. All rights reserved. This is a purely academic website and images and text may not be copied for publication or for use on other webpages or for any commercial activity. A reasonable number of images and some text may be used for non-commercial academic purposes, including field trip handouts, lectures, student projects, dissertations etc, providing source is acknowledged.

Disclaimer: Geological fieldwork involves some level of risk, which can be reduced by knowledge, experience and appropriate safety precautions. Persons undertaking field work should assess the risk, as far as possible, in accordance with weather, conditions on the day and the type of persons involved. In providing field guides on the Internet no person is advised here to undertake geological field work in any way that might involve them in unreasonable risk from cliffs, ledges, rocks, sea or other causes. Not all places need be visited and the descriptions and photographs here can be used as an alternative to visiting. Individuals and leaders should take appropriate safety precautions, and in bad conditions be prepared to cancel part or all of the field trip if necessary. Permission should be sought for entry into private land and no damage should take place. Attention should be paid to weather warnings, local warnings and danger signs. No liability for death, injury, damage to, or loss of property in connection with a field trip is accepted by providing these websites of geological information. Discussion of geological and geomorphological features, coast erosion, coastal retreat, storm surges etc are given here for academic and educational purposes only. They are not intended for assessment of risk to property or to life. No liability is accepted if this website is used beyond its academic purposes in attempting to determine measures of risk to life or property.

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Dr Ian West, author of these webpages

Webpage - written and produced by:


Ian West, M.Sc. Ph.D. F.G.S.

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at his private address, Romsey, Hampshire, kindly supported by Southampton University,and web-hosted by courtesy of iSolutions of Southampton University. The website does not necessarily represent the views of Southampton University. The website is written privately from home in Romsey, unfunded and with no staff other than the author, but generously and freely published by Southampton University. Field trips shown in photographs do not necessarily have any connection with Southampton University and may have been private or have been run by various organisations.

Ian West was born in the London suburbs, but had family connections with Bournemouth. He came down to Bournemouth to live there in the Second World War and saw German planes close up in the town. Later he went to Bournemouth School and privately studied geology and collected fossils at Barton-on-Sea etc. He lived in Gerald Road, Bournemouth and later in a red brick house in Wildown Road, Southbourne, initially with a view of Hengistbury Head. He was a member of Bournemouth Natural Science Society. After studying geology in the RAF (national service) he returned to Bournemouth and commuted daily by steam train to Southampton University, where he has been a Member of Staff for 57 years so far. Ian knows Bournemouth very well, but now lives at Romsey on the other side of the New Forest and nearer to the University. He frequently visits the Bournemouth cliffs.
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