West, Ian M. 2013. Lulworth Cove, Dorset: Select Bibliograpy; Geology of the Wessex Coast. Internet site: www.southampton.ac.uk/~imw/lulref.htm. Version: 16th December 2013.

Lulworth Cove Geology Bibliography

Ian West,
Geology Wessex Coast, Romsey
and:
Faculty of Natural and Environmental Sciences
Southampton University,

Webpage hosted by courtesy of iSolutions, Southampton University

Click here for the full LIST OF WEBPAGES

(You can download this educational site to SurfOffline, WebCopier or similar software to keep a safe permanent offline copy, but note that at present there is periodic updating of the live version.) |Home and List of Webpages |Lulworth Cove |Stair Hole, Lulworth |Fossil Forest | Dungy Head | Durdle Door | | Purbeck Palaeoenvironments |
Click here for the full LIST OF WEBPAGES
Selected external links: | Jurassic Coast (DCC)| Lulworth Cove Heritage Centre


Go back to the Lulworth Cove field guide?


Contents

1. MAIN LIST - undivided publication list, geological and general
2. Conservation - Geological
3. Chalk
4. Geomorphology
5. Maps - Geological and Topographic
6. Portland Group
7. Purbeck Formation
8. Quaternary - Dolines and Solution Pipes etc.
9. Safety and Rock Falls
10. Structural Geology and Tectonics
11. Upper Greensand (Albian)
12. Wealden

Go back to top

Select Bibliography on the Geology of the Lulworth Cove Area

Go back to top

Internet Sites Relevant to the Geology of the Lulworth Area

Go back to top

1. MAIN LIST - General, Undivided - Geological and Geomorphological, with some non-geological publications (the other lists are incomplete and will be removed progressively)


..
Allen , P. 1976. Wealden of the Weald: a new model. Proceedings of the Geologists' Association, 86 (4) 389-437. [By the late Professor P. Allen of Reading University, well-known specialist on Wealden sedimentology]. Abstract: Wealden of the Weald: a new model. Proc. Geol. Ass., 86 (4), 389-437. An alternative to the deltaic model is presented. The Weald is seen as a subsiding graben-basin, with 'Macaraibo' sedimentary features, spasmodically open to the sea and margined by active horsts. Channel-facies are commoner in the Wealden sand and clay formations than previously suspected. The 'normal' environment was a variable-salinitv coastal mudplain with lagoons and sandy water-courses loosely connected north-westwards with the East Anglian Sea. Channel patterns fluctuated across the low - high sinuosity transition. Periodically, increased riverflow transformed parts of the basin into sandy braidplains, culminating sometimes in coalescent alluvial fans. These interruptions were brief and generated by marginal upfaulting of surrounding blocks combined with attendant climatic changes. Large expanses of alluvial plain were bare of trees and bushes, but supported rich growths of herbaceous pteridophytes where deposition and erosion became inactive temporarily. Herds of dinosaur travelled freely across the basin and maintained themselves in it. The climate was warm, with marked wet and dry seasons and, possibly, diurnal rhythms in precipitation. Its general trend was towards 'amelioration', as though Britain was leaving the Purbeck semiarid zone and moving across the warm temperate belt. Following mid-Purbeck earth movements and the final Cinder Bed transgression, the London-Kent horsts dominated Hastings times, being the main suppliers of arenaceous sediment and controlling water-salinity by acting as imperfect barriers against further inroads by the northern sea. On two occasions (Ashdown and Lower Tunbridge Wells formations) the channel-networks merged to build up a single braidplain spanning the basin. Bedload from Wessex and the Isle of Wight stopped short at the Hampshire-Sussex border, though some Norman sand may have reached south-east Sussex. During Weald Clay times the London and Kent blocks ceased to be important sources of sediment, the former letting in the muddy 'Snettisham' Sea voluminously. Several of the brackish-marine inundations sprinkled East Anglian sand across the north-west Weald. mixing it with 'London' gravel gathered up in passing. But most of the sand, now sparse, was generated by jolts in distant Cornubia and Armorica, rejuvenating the rivers and causing the Wessex alluvia to probe the western Weald. After their Horsham premiere the movements weakened, the younger sands reaching less far eastwards and becoming more restricted to their channel systems. Least affected by tectonic and marine influences were the eastern parts of the basin. The regional palaeoslope in the Anglo-French area seems to have tilted northeast, away from the ruptured continental margin, preluding increased spreading rates in the mid-Cretaceous Atlantic. There is no room in the new model for large-scale classical deltaic processes or for the traditional derivation of the immature 'western' detritus from Hercynian granites (or any other granites). The model removes some previous difficulties, e.g. the small sizes of the London catchments, the rapidity of many sedimentological changes and the paradox that both marine and fluviatile invasions appear to come from the same general direction. In the field, the well-known 'Rocks' (massive sandstone members) become the merged multistorey networks of braided channel-fills formed during climactic phases of uplift and river-rejuvenation on the basin margins.
..
W.J. Arkell The late Dr William Joscelyn Arkell of Oxford University, famous expert on and author of many publications on the Jurassic System. From a painting commissioned by Shell Oil Co. for an International Symposium on the Jurassic System. The photograph was kindly provided by Professor Michael House, the well-known Dorset Jurassic author and once a research student of Dr Arkell.
Arkell, W.J. 1933. The Jurassic System in Great Britain. Clarendon Press, Oxford, 344p. By Dr. William Joscelyn Arkell, Oxford, January 1933.

Preface:
In England, in the sphere of Jurassic geology, we are wardens of a classic area, for our cliffs and quarries are the standards of comparison for the whole world. A German authority, Dr. Hans Selfeld, remarked after a brief study in 1914. 'Research on the faunas and their successions shows that the English Upper Jurassic can be taken as the type of that of North-West Europe, in the most complete development anywhere yet known.' He had studied only the Upper Jurassic, but the same could with equal truth be said of the Lower.
This is no mean heritage. In our Jurassic rocks all the principles of stratigraphy are illustrated perhaps more clearly than in any other part of the geological record. Palaeontologically, too, the system contains an unequaled wealth of materials; and for the evolutionists, the ecologist and palaeogeographer no more favourable field exists.
The aim of this book is, first and foremost, to provide a general description of the Jurassic rocks of the British Isle, indicating what work has been done and where the information is to be obtained, and to illustrate some of the magnificent type-sections. It has been found that to give even an outline account of the rocks and the various changes that they undergo as they are traced across the country, pointing out the presence and significance of discordances, and arranging the facts in sequence as data for the elucidation of earth-history, is a matter of considerable difficulty within the limits of one volume.
[...continues]

Arkell, W.J. 1935a. The Portland Beds of the Dorset mainland. Proceedings of the Geologists' Association, 46, 301-347.

Arkell, W.J. 1935b. Analysis of the Mesozoic and Cainozoic folding in England. Report of the 16th International Geological Congress, Washington, 1933, 937-952. Arkell , W.J. 1936. The tectonics of the Purbeck and Ridgeway Faults in Dorset. Geological Magazine, 73, 97-118.

Arkell, W.J. 1938a. Three tectonic problems of the Lulworth district: studies of the middle limb of the Purbeck Fold. Quarterly Journal of the Geological Society, London, 94, 1-54. By William Joscelyn Arkell, M.A., D.Sc., F.G.S. No abstract. Example extract: Introduction etc.: "Of all the folds thrown up across the Chalk plains of North-West Europe during the Alpine orogeny, the most interesting and the most perfectly exposed is the Purbeck anticline. In the cliffs of the Dorset coast the sea has laid bare all parts of the structure, from the core or crestal region, through the vertical and overturned middle limb and the "foresyncline" (Busk 1929, p. 29), into the foreland, where the Upper pretaceous rocks are seen reposing with sharp unconformity upon a previously folded and eroded Jurassic foundation. The general and some special aspects of the fold and its associated faults have been discussed in a previous paper (Arkell, I936). The present paper results from a study of the middle limb, where it is dissected by the sea cliffs of the Lulworth district. These cliffs have long been renowned for their beauty, but their marvellous tectonic features, both great and small, have been neglected, with the result that their value to students of tectonics has not been fully utilized. The first three parts of the paper attempt a solution of the three most outstanding problems: contortions in the Purbeck Beds, the Purbeck Broken Beds, and the abnormal attenuation of the strata towards Durdle Door. The fourth part offers an interpretative essay and synthesis. The area dealt with is included in sheet 342 of the Geological Survey one-inch map and sheet 141 of the Ordnance Survey one-inch map.
Contortions in the Purbeck Beds: (a) Description. The contortions in the Purbeck Beds at Stair Hole are illustrated in Pl. I. The top of the Portland Stone and the hard "Cap" limestones of the basal Purbeck Beds dip northward at 40°, forming the arches through which the sea enters. In the sides of the little recess the rest of the Purbeck Beds, above the top of the Cypris Freestones, consisting of alternations of limestone and marl, shale, or clay seen in dipsection, begin to assume from below upwards an increasingly large knee-shaped anticlinal bend. The apex of the bend is directed upwards and outwards, towards the north, with the short horizontal limb to the south. The longer limb stands vertical or slightly inverted, and where the beds composing it plunge below the beach they are directed to meet the top of the Cypris Freestones at an angle of 50°. In the Corbula and Beef Beds (upper part of the Middle Purbeck) and Upper Purbeck strata, the sharp apex of the anticline becomes blunter with increasing size. In these beds, near the top of the east cliff, a second but smaller sharp anticline develops above the horizontal limb of the other. This is of the same type as the larger flexure, with the apex pointing in the same direction, but it is more overturned northwards, and it does not affect strata below the Cinder Bed. There are signs of a third fold just below the top of the cliff, but the upward continuation has been eroded away. The intervening synclines are closed and approaching recumbent. This structure, which may be called the Lulworth crumple, is continued in the direction of strike for a visible distance of a mile and a half, but the other sections are not so good. On the west side of Stair Hole (Pl. I and Fig. 4) only the main anticline and syncline are seen, at a higher elevation above the beach, showing that the crest-line is rising westward. At Dungy Head and Durdle Door only the lower part of the structure survives, truncated by the cliff top...."[continues].

Arkell, W.J. 1938b. The Purbeck Broken Beds. Geological Magazine, 75, 333-334.

Arkell, W.J. 1940. Dorset Geology 1930-1940. Proceedings of the Dorset Natural History and Archaeological Society, 61, 117-135.

Arkell, W.J. 1941. The gastropods of the Purbeck Beds. Quarterly Journal of the Geological Society, London , vol. 97, part 1, 79-128. [Example extract - the start - follows:]
Isolated occurrences of genera such as Viviparus and Valvata are known in Bathonian, Liassic and more doubtfully even earlier rocks, but the earliest assemblage of a dozen genera of unequivocally freshwater molluscs is found in the wonderful fauna of the Purbeck Beds. Attention was first called to it by Thomas Webster (1816, pp. 191-2) (see below, p. 81). His remark, "It is rather surprising that this very ancient freshwater formation should not have excited more attention," might almost be said to be still true; for since J. de C. Sowerby figured a couple of species of Viviparus from the Purbeck Beds in 1826 and six species of lamellibranchs in that year and in 1836 (in Fitton's memoir), no further Purbeckian mollusca have been adequately figured in this country or described in the English language.
Edward Forbes was preparing a monograph on the invertebrate fauna of the Purbeck Beds when his work was cut short in 1854 by his death at the age of 39. All that appeared was a preliminary account, in which the genera Viviparus, Valvata. Lymnaea, Planorbis, Hydrobia, Physa, Melania, Cyclas, and Unio were recorded, and also many marine genera, but no species were mentioned. A number of MS. names were introduced by him on labels and in the Survey catalogues, and some of them have been used by other authors, but if any manuscript or type specimens existed they have disappeared.
In 1856 Osmund Fisher published a detailed account of the stratigraphy of the Dorset Purbeck Beds, recording all the genera mentioned by Forbes and assigning them to their precise horizons. H. W. Bristow also noted many of them in his vertical sections of the Geological Survey, sheet 22 (1857). A useful reprint of the Durlston section with the beds numbered was published by Damon (1884, pp. 201-209).... [continues with systematic descriptions from page 83 onwards].

Arkell, W.J. 1947. The Geology of the Country around Weymouth, Swanage, Corfe and Lulworth. Memoir of the Geological Survey, 386 pp. The standard older publication on the area.

Arkell, W.J. 1940. Dorset Geology 1940-1950. Proceedings of the Dorset Natural History and Archaeological Society, 72, 176-194.

Arkell, W.J. 1956. Jurassic Geology of the World. Oliver and Boyd.

Arkell, W.J. and Tomkeieff, S.I. 1953. English Rock Terms: Chiefly used by Miners and Quarrymen. Oxford.
..
Ashley , H. 1992. The Dorset Coast: History, Lore and Legend. Countryside Books. Newbury Berkshire. 127 pp.

Go back to top


.
Barrois , C. 1875. Ondulations de la Craie dans le Sud de l' Angleterre. Ann. Soc. Geol. Nord, 2, 25.

Barrois, C. 1876. Recherches sur le Terrain Cretace Superieur de l'Angleterre et de l'Irlande. Mem. Soc. Geol. Nord (Summ. in Ann. Soc. Geol. Nord, 3, 189).
.
BBC News Website . 2007. Cliff walker fell 200ft to death. Mr Preston was found by rescue teams searching for two missing fishermen A 25-year-old medical student died after falling 200ft (60m) down a sheer cliff onto a beach while walking along a beauty spot on the Dorset coast. An inquest heard how Benjamin Preston, from Evershot near Dorchester, suffered massive head injuries in the fall on 16 December last year. His body was found at White Nothe, near Weymouth, by rescue teams searching for two missing fishermen....
Dc Cottrell told Bournemouth, Poole, and East Dorset Coroner's Court there were no foot marks on the shingle beach, indicating he had fallen. He said: "It was a 200ft sheer cliff. He was fully dressed in outdoor clothing, wearing a backpack. He appeared to be dressed as if walking the cliff. "The footpath that is regularly used is very close to the cliff edge. There is nothing to stop anybody from accessing the cliff edge." ..[continues]
..
Bevan , T.G. 1985. A reinterpretation of fault systems in the Upper Cretaceous rocks of the Dorset coast, England. Proceedings of the Geologists' Association, London, 96, 337-342. Mesofault systems in the Upper Cretaceous rocks of the steep limb of the Purbeck monocline are reinterpretated by analysing their geometry with reference to the orientation of sedimentary layers. As a consequence of using layering as a datum rather than the horizontal, the five original groups of mesofaults, previously recognised by Arkell and Phillips, have been condensed into two sets of conjugate extension faults. These faults are symmetrically arranged about the layering, the dip of which varies from vertical to steeply inclined. Mesofaults previously considered to have been generated during a complicated history of thrusting, related to the tightening of the synformal bend of the monocline and horizontal compression, are reinterpreted as being the result of layer-parallel extension during flexuring. Thus they are accomodation structures formed during the development of the monocline, itself related to drape over reactivated Jurassic growth faults during N-S shortening. South-dipping reverse macrofaults are reinterpreted as being the continuation to the surface of the reactivated Jurassic growth-faults, whilst north-dipping reverse macrofaults are interpreted as being antithetic to these reactivated faults. A tectonic implication arising from the proposed kinematic classification of the mesofaults is that they can be perceived as being the product of stretching of a steep fold limb during flexuring, rather than being related to several phases of horizontal compression.

Go back to top

British Geological Survey (BGS). (Compiled by M.A. Woods) 2011. Geology of South Dorset and South-East Devon and its World Heritage Coast.

The cover of the 2011 South Dorset Memoir of the British Geological Survey

An example page from the British Geological Survey, South Dorset Memoir, 2011

Special Memoir for 1:50,000 geological sheets 328 Dorchester, 342 West Fleet and Weymouth and 342/343 Swanage and parts of sheets 326/340 Sidmouth, 327 Bridport, 329 Bournemouth and 330 Newton Abbott. Compiled by M.A. Woods. By Barton, C.M., Woods, M.A., Bristow, C.R., Newell, A.J., Westhead, R.K., Evans, D.J., Kirby G.A., and Warrington, G. Contributors: Biostratigraphy - J.B. Riding; Stratigraphy - E.C. Freshney; Economic Geology - D.E. Highley and G.K. Lott; Engineering Geology - A. Forster and A. Gibson. British Geological Survey, Keyworth, Nottingham, 2011. 161 pp. This is the new version of the Geological Survey Memoir for the Dorset Coast etc. and replaces Arkell (1947) and the earlier memoir by Strahan (1898). It covers a wider area than these old memoirs, though, and includes all of "Jurassic Coast", UNESCO World Heritage Coast. It is a key reference work. Available from BGS Online Bookshop at 24 pounds stirling (in Jan. 2012).
.
Bigge, M.A. and Farrimond, P. 1998. Biodegradation of seep oils in the Wessex Basin- a complication for correlation. By M. Ashley Bigge and Paul Farrimond. Geological Society Special Publication. Vol 133, pp. 373-386.
Abstract: A detailed organic geochemical investigation of seep oils from the Dorset coast has revealed notable variation in both the extent and pathways of biodegradation. All the seep samples analysed from Mupe Bay, Stair Hole (near Lulworth Cove) and Osmington Mills have had their n-alkanes and acyclic isoprenoid alkanes removed, but some samples are more extensively degraded, with partial loss of steranes and/or hopanes. At Mupe Bay (conglomerate matrix samples; see Parfitt and Farrimond 1997 this volume) the hopanes have been preferentially attacked, whilst at Stair Hole the steranes appear heavily degraded although there has been no alteration to the hopane distribution. 25-Norhopanes were not detected in any of the samples. Biological marker distributions of seep oils which have suffered no hopane or sterane biodegradation are compared with those of three reservoired oils from the area (Wytch Farm and Kimmeridge fields). Molecular parameters indicate significant variation in source rock facies and maturity within the oils of the Wessex Basin.
..
Bird , E. 1995. Geology and Scenery of Dorset. Ex Libris Press. Bradford on Avon. 207 pp. ISBN 0 948578 72 6.
.
Brannon , P.1860. The Illustrated Historical and Picturesque Guide to Swanage and the Isle of Purbeck: with a clear digest of the Geology and a Minute Description of the Coast from Bournemouth Bay to White Nore. by Phillip Brannon, Architect, C.E. etc. Poole, Published by R. Sydenham, London, Longman and Co. 2nd Edition. 106 pp. See p. 79 - 84 on the Lulworth area. "The Sectional Bays of Bindon Liberty. Our description presumes that a boat has been taken from Kimmeridge or Tineham, and that it is at times resorted to as far as Ringstead Bay, on account of the deep and numerous sinuosities of the coast, and many otherwise inaccessible points. - We have chosen the above as the most suitable title for this extraordinary line of coast, the features of which we shall sketch as distinctly as our narrow space admits." [The author gives old and interesting names for various rocks, cliffs and valleys. The geology is in very simple terms. There are some interesting etchings in an exaggerated style.]

Brannon , P. 1864. Sea Coast Retirement at West Lulworth. Sydenham. London.
.
Bruce , P. 1989. Inshore Along the Dorset Coast. Boldre Marine, Kestral Cottage, Shirley Holms, Lymington, Hampshire, SO41 8NH, Tel. 0590 - 683106. 115 pages + maps. Price was £9.95. [This is useful for topographic details and names of rocks, coves and embayments etc.] See also later edition.

Bruce , P. 2001. Inshore along the Dorset Coast. Third Edition, Boldre Marine, Lymington. 134pp. Paperback. ISBN 1-871680-26-3 By Peter Bruce. Price was £14.95. From the back cover blurb: This is a book for seafarers and landsmen who have reason to visit the exceptionally beautiful and interesting east Dorset coast. It covers the area from Christchurch Bay to Portland Bill and gives in detail all the nautical lore, delights, tidal streams and history that most people would ever want to know. Every bay, every landing place and every feature has been surveyed in detail and researched to provide expert local knowledge. Furthermore the text is richly illustrated by superb aerial and sea level colour photographs which add considerably to the value of this unique book for those who venture on the water in any kind of craft, or for those who are curious about marine aspects of the coastline. [This book is very useful for local names and coastal detail for the eastern Dorset coast. This edition has very good colour photographs, many of them aerial photographs.]
..
Brunsden , D. and Goudie, A. 1981. Classic coastal landforms of Dorset. Geographical Association, Landform Guides, No. 1, 39 pp.
..
Buckland , W. 1837. Geology and Mineralogy considered with Reference to Natural Theology. William Pickering, London, Vols. 1 and 2. The Bridgewater Treatises on the Power Wisdom and Goodness of God as Manifested in the Creation, Treatise VI, 2nd Edition. [Published with funds left by the Right Honourable and Reverend Francis Henry, Earl of Bridgewater following his death in 1829. The Reverend William Buckland was Canon of Christ Church, and Reader in Geology and Mineralogy in the University of Oxford. Discusses the Fossil Forest].

Buckland, W. and De La Beche, H.T. 1835. On the geology of the neighbourhood of Weymouth and the adjacent coast of Dorset. Transactions of the Geological Society, London (2), 4, 1-46, pls. 1-3. [Discusses the Fossil Forest.]
..
Burton , E. St.J. 1937. The origin of Luworth Cove, Dorset. Geological Magazine, 74, 377-383.
..
Canning , A. D. and Maxted, K.R. 1979 (reprinted 1983). Coastal Studies in Purbeck: A Geographical Guide. Printed and Published by the Purbeck Press, Swanage, Dorset. 86 pp., paperback, ISBN 0 906406 07 2 [monochrome booklet].
..
Casey , R. 1963. The dawn of the Cretaceous Period in Britain. Bulletin of the South-East Union of Scientific Societies, Bulletin No. 117, 1-15. Preprint of Presidential Address to the Geological Section. Tunbridge Wells, 11th April 1963. "Some regimes were born in violence and others flowed in on a silent tide. So it is in geology. Not every page of Earth's history is numbered by crustal upheavals, volcanic outbursts and similar revolutions: all too often it is hard to tell where one chapter ends and the other begins..." [This has been a key paper in linking the Cinder Bed with the basal Cretaceous transgression of the Boreal Realm. This interesting correlation with the Boreal Jurassic/Cretaceous boundary has been largely overshadowed by later work. New evidence has made it possible to relate the Purbeck lagoonal succession to the marine Jurassic/Cretaceous boundary as defined in southern France. This is not of the same age as the Russian Jurassic/Cretaceous boundary. A local bioproduct of placing the Jurassic/Cretaceous boundary in the middle of the Purbeck sequence in southern England has been to create a terminological problem. Because chronostratigraphy and lithostratigraphy were not correctly separated, this paper split the Purbeck into two mixed chronostratigraphic and lithostratigraphic subdivisions - the "Lulworth Beds" below the Cinder Bed and the "Durlston Beds" for the Cinder Bed and overlying strata upto the Hasting Beds (lower part of the Wealden). The "Lulworth Beds" were to be grouped with the Portland, and the "Durlston Beds2 as part of the Wealden, although this did not happen. Unfortunately, the base of the Cinder Bed was taken as a chronostratigraphic boundary, the J-K Boundary, but the Portland/Lulworth Beds boundary was placed lithostratigraphically and the Durlston Beds/Hastings Beds boundary was also placed on lithostratigraphic criteria. This unsatisfactory nomenclature later became used by others authors to create the so-called "Lulworth Formation" and "Durlston Formation". However, they are only names and probably some people find them convenient. The present author does not see any use for them and considers that they should be abandonned, with a return to the "Purbeck Formation". Nevertheless, this is only one aspect of Casey's paper and there is much in it of value. It provides useful information on correlation within Britain, and on various details of strata tied in with the Cinder Bed. Casey's 1963 paper is not easily found but contains much interesting material and is well-worth reading.]
..
Cobban , W.A., 1983. Molluscan fossil record from the Northeastern part of the Upper Cretaceous Seaway, Western Interior. In Cobban, W.A. and Merewether, E.A.: Stratigraphy and paleontology of Mid-Cretaceous rocks in Minnesota and contiguous areas. Geological Survey (of USA) Professional Paper 1253 1-25 and 15 plates.
..
Clements , R.G. l973. A Study of Certain Non-Marine Gastropods from the Purbeck Beds of England. Unpublished Ph.D. Thesis, University of Hull, 49l pp.

Clements, R.G. 1969. Annotated cumulative section of the Purbeck beds between Peveril Point and the Zig-zag path, Durlston Bay. In: H.S. Torrens (Ed.) International Field Symposium on the British Jurassic, Excursion No. 1, Guide for Dorset and South Somerset. University of Keele, pp. 44-71. 71p. total.

Clements, R.G. 1993. Type-section of the Purbeck Limestone Group, Durlston Bay, Swanage, Dorset. Proceedings of the Dorset Natural History and Archaeological Society, 114 for 1992, 181-206. [Classic section log.]
..
Cleevely , R.J. and Morris, N.J. 2002. 7. Introduction to Molluscs and Bivalves [of the Chalk]. Pp. 99-160 in: Smith, A.B. and Batten, D.J. 2002. Fossils of the Chalk. Palaeontological Association, Field Guides to Fossils: Number 2, Second Edition, revised and enlarged. The Palaeontological Association, London. 374 pp. ISBN 0 901702 78 1. Price £14 paperback.
.
Cope, J.C.W. 2006. Upper Cretaceous palaeogeography of the British Isles and adjacent areas Proceedings of the Geologists' Association, London, 117, 129-143. By Professor John Cope, Department of Geology. National Museum of Wales, Cathays Park, Cardiff CFIO 3NP. UK.
Abstract: The Upper Cretaceous sub-Period saw the deposition of the Chalk over much of the British Isles region, with progressively inundated land areas. By the Late Maastrichtian land areas were at their minimum and a thick Chalk sequence accumulated over the region. In the Early Palaeocene uplift in the Irish Sea interrupted deposition, but in many areas marly chalk deposition resumed. Mid-Palaeocene uplift led to dramatic erosion of this cover so that in most places all the Danian, Maastrichtian and, in some places, Campanian and even Santonian Chalk were removed before deposition of Late Palaeocene sediments; this widespread and pervasive erosional event has masked the true extent of Maastrichtian deposition. In areas outside the Palaeocene basins erosion of the Chalk continued, rapidly exposing underlying rocks. [Not specifically on Lulworth Cove but a key paper on Chalk palaeogeography with a very good reference list of Chalk publications.]

Cope , J.C.W. 1974. Vertical pipes in the Dorset Chalk. Proceedings of the Dorset Natural History and Archaeological Society, 95, p. 105.

Cope, J.C.W. 2012. Geology of the Dorset Coast. Geologists' Association Guide, No. 22. 232pp., with many colour photographs and diagrams. New edition by John C.W. Cope. (See also the earlier editions by House, M.R. 1989 and 1993.)
.
Coram , R.A. 2003. Taphonomy and ecology of Purbeck fossil insects. Acta Zoologicica Cracoviensia, 46 (supplement - Fossil Insects), 311-318, Krakow, 15 October, 2003. Accepted for publication: 2002. By Robert A. Coram of Swanage, Dorset, UK.
Abstract. The basal Cretaceous Purbeck Limestone Group of southern England yields many fossil insects and study of their taphonomy allows a preliminary reconstruction of their life habitats. The aquatic fauna comprises a low diversity brackish water assemblage as well as transported remains of probably fresher water taxa. The terrestrial fauna comprises largely woodland inhabitants that generally became disarticulated prior to arrival at the site of deposition. [end of abstract].
Example extract from text:
1. Introduction and Geological Background:
The Purbeck Limestone Group, best exposed in Dorset, southern England, consists mainly of lagoonal sediments currently considered to be basal Cretaceous (Berriasian) in age (Allen and Wimbledon, 1991). Fossil insects are found at many horizons and can be very abundant, occurring in their hundreds on some bedding planes. They can be found at many coastal and inland quarry localities in Dorset, but the majority have come from the Purbeck type section at Durlston Bay, near Swanage (National Grid Reference SZ 035780), which is still productive (Fig. 1). Seventeen orders of Purbeck insects have been recognised and about 200 species have been described, although a far greater number await description (Coram and Jarzembowski, 2002). This paper is a preliminary attempt to divide the Purbeck insect fauna into broad environmental categories on the basis of their taphonomy and to make some taphonomic comparisons with other deposits of similar age. The Purbeck Limestone Group is divided into a lower Lulworth and upper Durlston formations. It is underlain by limestones of the Tithonian (Upper Jurassic) Portland Limestone Group containing a normal marine fauna, including giant ammonites, and is succeeded by non-marine, predominantly fluvial, deposits of the Wealden Group extending to the Upper Barremianl earliest Aptian. These are also insectiferous (Jarzembowski, 1984), providing the opportunity to track changes in the insect fauna through much of the Lower Cretaceous in southern England... [continues with a map of Dorset outcrops, three photographs of slabs with insects, a diagram showing ordinal representation of insect fossils in the Corbula Beds, and a good full-page diagram of the inferred life habitats of various Purbeck insects (dragonfly nymphs and chironomids in the brackish lagoon; beetles and cockroaches on the shell beach or sabkha; bugs and fly larvae in the freshwater lake; crane flies, gnats and midges in the damp forest; orthoptera in the open glades; snake flies, fungus gnats, cupedid beetles, buprestid beetles, aphids and plant bugs in the forested land).]
.
Crewe , R.J. 1977. Dorset: Rock Climbing Guide. Published by R.J. Crewe. ISBN 094405044. 235 pp. A small section only on the Lulworth Cove area. See pages 145 - 158. Lulworth and Portland. - specific climbs - Arthur's Mount; Stair Hole Bastion; Intermediate Slabs and Problem Corner etc. The one-mile difficult Lulworth Cove - Mupe Bay Traverse; Credo; Durdle Door; Exfoliator etc. [several of these are listed as severe, very severe or hard severe. They obviously should not be attempted by anyone not expert, not knowledgable about the route or not properly equiped. There have been a fatal accident on the outer cliffs near the Fossil Forest.]
.
Damon, Robert,

Robert Damon, 1814-1899, was a well-known Dorset geologist and collector of and dealer in fossils. He was born in Weymouth, with origins in a Flemish family. He ran a fossil shop at Augusta Place, the Esplanade, Weymouth. This shop is now a fish and chip shop (information kindly provided by his great, great grandaughter - Carole Burridge - nee Carole Damon, who lives in Bridport). Robert Damon was a Member of the Imperial Natural History Society of Moscow, and visited Russia in 1883, bringing back samples. His books are extremely interesting, with many diverse footnotes and sidelines. Robert Damon made a private collection of 400 Dorset fossils to illustrate his books. The Victoria Museum, Australia has ichthyosaurs from Damon, and many other museums contain fossils of his.

Damon , R. 1860. Handbook to the Geology of Weymouth and the Isle of Portland; with Notes on the Natural History of the Coast and Neighbourhood. By Robert Damon. Accompanied by a map of the district, geological sections, plates of fossils, coast views, and numerous other illustrations. London, Edward Stanton, 6 Charing Cross, 1860. This edition is available online in Google Book Search. The second edition, listed below is mostly the same but with some additions.

Damon , R. 1884. Geology of Weymouth, Portland, and Coast of Dorsetshire, from Swanage to Bridport-on-the-Sea: with Natural History and Archaeological Notes. New and Enlarged Edition (2nd Ed.), Weymouth, R.F. Damon, London, Edward Stanford. 250p. With a colour geological map of part of the Dorset coast, and including a log of the Purbeck strata of Durlston Bay, Swanage, by H. W. Bristow and Prof. E. Forbes (although note that it contains a small error). (A copy of Damon's second edition is in the possession of Ian West)
Preface to Second Edition
Since the issue of the First Edition increased attention has been given to the Geology of the coast of Dorsetshire, especially in the contributions of Messrs. Blake and Hudleston, and Professor Prestwich, which in part have been embodied in the present volume.
Elementary and explanatory notes are given for the use of those young in the study of the science.
A description of the geological formations of Swanage and Bridport, the two extremes of the district under consideration, is for more convenient reference placed towards the end.
The Geological Survey of this district was almost entirely made by Mr. Henry W. Bristow, Senior Director of the Geological Survey of Great Britain. To him I am greatly indepted for a final revision of the work. Mr. W. Topley, of the Survey, has also kindly given much assistance, as have also Messrs. G. Sharman and E. T. Newton with the lists of fossils. Mr. Etheridge has favoured me with the Bridport portion of his unpublished sections of the Oolitic rocks of England.
The works I have consulted are necessarily very numerous, and to their respective authors I acknowledge my great obligations.
To the above and other friends, who have kindly responded to my enquiries for information, my sincere thanks are rendered.
R. Damon
Weymouth, October 1884.
..
Davies , G.M. 1935. The Dorset Coast: A Geological Guide. Thomas Murby and Co. London. 1st edition. Extract from Preface to the First Edition: "The experience of many years has proved the Dorset coast to be an ideal training ground for field parties of geological students. There the beginner sees folds and faults as clearly recognisable as in text-book diagrams, while the advanced student finds many problems still inviting investigation. The fossil collector can make large bags, and the geographer, seeing how clearly surface features mirror the underlying structure, is more than ever convinced that geology is the foundation of geology.... It is primarily for such students that this book has been written...

Davies , G.M. 1956. The Dorset Coast: A Geological Guide. Adam and Charles Black. London. 2nd edition, 128 pages.
..
Defoe , D. 1705 [Probable date. Refers to 1703 storm which was obviously then recent and contains many letters dated 1704. Date not seen on the title page.] A Collection of the Most Remarkable Casualties Disasters which happen'd in the Late Dreadful Tempest both by Sea and Land on Friday the Twenty-fixth of November, Seventeen Hundred and Three. To which is added Several Suprising Deliverances. The Natural Causes and Original of Winds. Of the Opinion of the Ancients that this Island was More Subject to Storms than Other Parts of the World. With Several Other Curious Observations upon the Storm. The Whole Divided into Chapters under Proper Headings. 2nd Ed. George Sawbridge, London, 272 pp. [Notes: Wednesday 24th Nov. 1703. Start of storm. Mercury abnormally low. Wind direction SW by S or near S in the beginning and veered WSW towards end. Reports of earthquake. Spring tide high at 4 am when storm blowing. "A prodigious tide happen'd the next day but one, and was occasion'd by the fury of the winds".]
..
Donovan , D.T. and Stride, A.H. 1961. An acoustic survey of the sea floor south of Dorset and its geological interpretation. Philosophical Transactions of the Royal Society, Series B, 244, 299-330.
.
Dorey, W. 2004. Memories of Old Lulworth. Walter Dorey, Printed by Dolphin Printers, Poole. 29 pp. With editorial assistance from Janet Dorey. Booklet with monochrome and colour photographs, available for £2.99 at the Heritage Centre, Lulworth Cove. This is not geological but contains local historical information. There a few notes which might be of geological or geographical interest.
Notes: The brick water pumping station at Lulworth Cove was built in 1934, with two diesel engines and an electric one. It is not in use now. The supply was taken from the spring which rises between Cove Cottage and Spring Cottage. This went dry when Walter Dorey was young. a borehole was sunk outside the wall [of the pumping station?]. The Wessex Water Board took over on the 1st October 1976.
There was a well on the corner of no. 16 Main Road and one at the rear of Churchfield House, and Walter Dorey has a vague recollection of one at the rear of no. 29 and another in Grafton hedge. These wells were all filed in too.
There was an old reservoir under Bindon Hill above the school.
The Beach Cafe was once Henry Caffey's coal store in the days when coal was delivered by sea.
Sewage was at one time discharged from a pipe amongst the rocks near West Point below the Coastguard look-out (since collapsed). In the 1930s a new sewer was installed and this went through the cliff and discharged outside of the cove. Now sewage is diverted to Hambury Farm and goes through a macerator before it enters the sea.
..
Drummond , P.V.O. 1967. The Cenomanian Palaeogeography of Dorset and Adjacent Counties. Ph.D. Thesis, University of London. This is the results of Ph.D. research at Chelsea College of Science and Technology under the supervision of Dr. W.E. Smith, the specialist on the Cenomanian Limestone of Beer in East Devon.

Drummond , P.V.O., 1970. The Mid-Dorset swell: evidence of Albian-Cenomanian movements in Wessex. Proceedings of the Geologists' Association, 81, 679-716. Abstract: The Upper Cretaceous succession of Wessex was intermittently interrupted by periods of mild movements which were responsible for the numerous diastems within the Upper Albian-Cenomanian sequence. Important phases of activity involving the slight elevation of small periclines occurred at the close of the Mortoniceras inflalum Zone, Lower and Middle Cenomanian times. Of particular importance was a persistent line of periclines coincident with a north-west-south-east trending belt of thinning within the Upper Albian and Cenomanian sequences extending from central Dorset to the Isle of Purbeck and on toward the Isle of Wight. This structure (the Mid-Dorset Swell) had a profound effect upon Vraconian-Cenomanian sedimentation, causing extensive reworking, condensation and erosion of deposits over its crest, and separated a south-western shallow-water limestone province (the Wessex Shelf) from a north-eastern deeper-water chalk-greensand province (the Wessex Trough). The Mid-Dorset Swell was responsible for the isolation of the Vraconian Chert Beds into three distinct basins, for the restriction of Cenomanian Limestone sensu lato to the Wessex Shelf, and for confining the Cenomanian Chalk Marl within the Wessex Trough. The progressive overlap of the Chalk Marl up the eastern flank of the Mid- Dorset Swell enhances the stratigraphical break between the Vraconian and the Cenomanian, until eventually the Grey Chalk oversteps on to M. inflatum Zone greensands along the crest of the Swell. During the Upper Cenomanian the Mid-Dorset Swell was dormant and uniform Grey Chalk, subject only to regional south-westerly shallowing, was deposited over most of the region. Across the Wessex Shelf the Grey Chalk has a condensed Basement-bed of fossiliferous pebbly Middle and Lower Cenomanian debris resting on the waterworn surface of the top Upper Greensand. The Upper Cenomanian ended with renewed movements which rejuvenated the Mid-Dorset Swell and caused some erosion of the Grey Chalk prior to deposition of the Turonian. [This is a key paper for understanding Late Kimmerian movements in the Lulworth area.]
..
El-Shahat , A. l977. Petrography and Geochemistry of a Limestone Shale Sequence with Early and Late Lithification: the Middle Purbeck of Dorset,England. Unpublished Ph.D.Thesis , University of Southampton. 295 pp. By Dr. Adam El-Shahat, later a Professor at El-Mansoura University, Egypt. Supervisor - Ian West.

El-Shahat, A. and West, I.M. 1983. Early and late lithification of some aragonitic bivalve beds in the Purbeck Group (Upper Jurassic - Lower Cretaceous) of southern England. Sedimentary Geology, 35, l5-4l. Abstract: Beds of euryhaline bivalves alternating with shales constitute much of the middle Purbeck Group. They originated on "tidal" flats at the western margin of an extensive brackish lagoon. When these shell beds are thin and enclosed in shale they are often still preserved as aragonite and associated with "beef", fibrous calcite formed during compaction. In most cases, however, the shell debris has been converted into calcitic biosparrudite limestones. A compacted type has been lithified at a late stage, after deep burial. In this, pyrite is abundant and most of the shell aragonite has been replaced neomorphically by ferroan pseudopleochroic calcite. A contrasting uncompacted type of biosparrudite is characterised by bivalve fragments with micrite envelopes. Shells and former pores are occupied by non-ferroan sparry calcite cement, and there is little pyrite. These limestones frequently contain dinosaur footprints and originated in "supratidal" environments where they were cemented early, mainly in meteoric water. Once lithified they were unaffected by compaction. This uncompacted type indicates phases of mild uplift or halts in subsidence. These shell-bed lithologies, and also intermediate types described here, will probably be recognised in other lagoonal formations.

Go back to top


.
Emerton, S., Muxworthy, A.R. and Sephton, M. A. 2013. A magnetic solution to the Mupe Bay mystery. Marine and Petroleum Geology, vol. 46, pp. 165-172. September 2013. By Stacey Emmerton, Adrian R. Muxworthy and Mark A. Sephton. Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
[This is an important paper regarding oil migration in the Wessex Basin!]

Highlights:
• The clasts hold a magnetic signal unlike the matrix indicating two phase staining.
• The clasts show similar directions and thus were soft when deposited into the bed.
• The clasts indicate the onset of oil migration in the Early Cretaceous.
• The matrix is consistent with today's magnetic field and is an active oil seep.

Abstract:
An outcrop of Wealden beds at Mupe Bay (UK) is associated with a key piece of evidence for the timing of hydrocarbon migration in the Wessex Basin. A conglomeratic bed contains oil-stained clasts and matrix that appear different upon superficial observation. Conventional interpretations assign differences to the erosion and transport of oil-cemented clasts by Wealden rivers before their incorporation into a later stained conglomeratic bed. This scenario constrains the onset of oil migration in the basin to the Early Cretaceous; however, arguments have been put forward for single phase staining.
Magnetic information may provide new ways to examine the Mupe Bay record of oil migration. Migrating fluids such as hydrocarbons have been shown to cause chemical conditions suitable for the alteration or formation of authigenic magnetite resulting in associated chemical remanent magnetization (CRM). Magnetic characterization reveals both the matrix and clasts contain multi-domain magnetite but abundant hematite only exists within the clasts. Hysteresis parameters show the matrix has more multi-domain and likely larger magnetic grains than the clasts.
Magnetic directions are different in the clasts and matrix supporting a two-phase oil-staining event. Moreover, paleomagnetic directions for the clasts after tilt correction (82.6°N and 155.2°E) are consistent with biodegradation processes in the Early Cretaceous. Consistent directions in separate clasts imply the biodegradation and magnetite formation took place following transportation and incorporation of the oil-cemented clasts into the conglomerate bed. Magnetic directions reveal that the Mupe Bay matrix has a remanent magnetization corresponding to today's magnetic field, confirming the matrix represents an active oil seep.
This study represents an unprecedented use of magnetic data to date the onset of oil migration in a basin. The classic two-stage oil-staining scenario, which constrains the onset in the Wessex Basin to the Early Cretaceous, is supported by our data.

Go back to top

Go back to top

.

Ensom , P.C. 1985. An annotated section of the Purbeck Limestone Formation at Worbarrow Tout, Dorset. Proceedings of the Dorset Natural History and Archaeological Society, Vol. 106 (for 1984, published in 1985), 87-91. [Important graphical log of the Purbeck strata of Worbarrow Tout, in the style of the classic Clements' section of Durlston Bay. Essential for any serious study of the Purbeck sequence at Worbarrow.]

Ensom, P. and Turnbull, M. 2011. Geology of the Jurassic Coast; The Isle of Purbeck; Weymouth to Studland.. By Paul Ensom and Malcolm Turnbull. Jurassic Coast Trust. Coastal Publishing, Wareham. 128pp. Price £9. 95p. This is a very well-illustrated guide with many good colour photographs that are labelled in terms of stratal units. The text is in easily-readable, non-specialist language. There is a glossary for non-geologists. Some further reading is given in a list at the back.



Ensom, P. 2010. The Purbeck Limestone Group (Tithonian-Berriasian) Succession Between Bacon Hole and Mupe Bay, near West Lulworth, Dorset. Proceedings of Dorset Natural History and Archaeological Society, vol. 131, pp. 140-144. By Paul Ensom, who has published many papers on the Purbeck Group and has logged the Worbarrow Tout, Purbeck section.

Example part of the three-page lithostratigraphic log for the Purbeck Group of Bacon Hole and Mupe Bay, Dorset, by Ensom (2010)

[This includes a very useful graphic log of 157 beds at Bacon Hole, shown in 3 pages.]
This log is Appendix 2 in: Ensom, P. 2010. Lithostratigraphic sections through the Purbeck Limestone Group (Tithonian-Berriasian) at five Regionally Important Geological/Geomorphological Sites (RIGS) on the Isle of Purbeck, and at Bacon Hole near West Lulworth, Dorset, southern England. Proceedings of the Dorset Natural History and Archaeological Society, vol. 131, 2010, pp. 127-144.

Go back to top

Evans, R. 2009. Boy Buried in Rockfall [at Black Rocks, Lulworth Cove]. Daily Mirror, short newspaper article by Rebecca Evans.
A boy of nine was seriously injured when he was crushed by a ton of rocks which tumbled from a seaside cliff yesterday as he played on a beach. He and a younger girl were on the sand when the boulders suddenly came crashing down, hitting them both. The boy was buried up to his neck and suffered bad injuries to his head, neck and spine.
He was airlifted to hospital where his condition was being assessed last night after the horrific accident at the picturesque Lulworth Cove in Dorset. The girl was less seriously hurt.
Two shocked bypassers dialed 999 after seeing the rocks smash into them. A coastguard spokesman said: "The lad was very lucky not to have been killed. "The first report we had was that rocks weighing at least a ton had buried him up to his neck. When the rocks fall from the cliff - and that is always a possibility around the Dorset coast because of the rock structure - they pick up speed as they tumble down.
The boy and girl from Romsey and Ringwood, Hants, were with their respective dad and mum, who were a couple on a day out to the cove. It is a popular tourist destination on the Jurassic Coast World Heritage Site.
There have been rockfalls there before and around 10 people are killed by similar incidents in Britain every year.
[On Sunday, July 7th 1957, there was a similar rock fall at Black Rocks, Lulworth Cove: "9 in Hospital after Cove Rock Fall". "Nine people hurt by rocks that fell 100 feet to a crowded beach at Lulworth Cove, Dorset, were still in hospital today. A spokesman at Dorchester County Hospital said that were "fairly comfortable". [- continues]. Of course, there will be another rock fall here sooner or later and the consequences could be worse. My comments - It is not that the cliff is much more dangerous than elsewhere; cliff commonly have rock falls. The problem here is that people sit on the beach here almost every day there is fine weather. Rock falls occur at many places; fatal rock falls occur where people go.]

Go back to top


.
Fisher , O. 1856. On the Purbeck strata of Dorsetshire. Transactions of the Cambridge Philosophic Society, 9, 555-581. [Classic early log of the Durlston section with useful faunal information. See Wilding, 1988 for biography of Osmond Fisher]
.
Fitton , W.H. 1835. Notice on the junction of the Portland and Purbeck strata on the coast of Dorsetshire. Proceedings of the Geological Society, 2, 185-187.

Fitton, W.H. 1836. Observations on some of the strata between the Chalk and the Oxford Oolites, in the south-east of England. Transactions of the Geological Society, London, 4, 103-389.
..
Folk , R.L. Spectral subdivision of limestone types. In: Classification of Carbonate Rocks (Ed. by L.C. Pray and R.C. Murray), pp. 62-84. Memoir of the American Association of Petroleum Geologists, No. 1. [This does not, of course, refer to Lulworth Cove but is relevant to naming of limestone rock types seen in the Purbeck Formation at the cove.]

Folk, R. L. and Pittman, J. S., 1971, Length-slow chalcedony: a new testament for vanished evaporites: Journal of Sedimentary Petrology, vol. 41, pp. 1045-1058.
..
Francis , J. E. 1983. The Fossil Forests of the Basal Purbeck Formation (Upper Jurassic) of Dorset, Southern England: palaeobotanical and palaeoenvironmental investigations . Unpublished Ph.D. Thesis, University of Southampton. 295 pp. By Dr. Jane Elizabeth Francis, now at Leeds University. Abstract: During the Upper Jurassic, coniferous forests grew adjacent to the Purbeck evaporitic basin in Dorset: The palaeobotany of the forests is described for the first time and the Purbeck forest environment reconstructed. The basal Purbeck Formation of Dorset was deposited during minor transgressive and regressive phases on the borders of a shallow hypersaline basin. The sediments include evaporites, hypersaline intertidal algal stromatolitic sediments and lagoonal pelletoid silts interbedded with supratidal algal mat sediments. The unusual features are brecciated calcrete and calcareous marls representing former forest soils. The trees which grew in the rendzina-like palaeosols of the Lower and Great Dirt Beds are now preserved in situ as silicified tree stumps and branches. They were drowned by rising hypersaline water and preserved within mounds of algal stromatolitic sediment. The wood was rapidly silicified by length-slow chalcedony (quartzine), a type of silica commonly associated with evaporitic environments. The fossil forests were dominated by one type of conifer belonging to the extinct family Cheirolepidiaceae. The wood of this is designated Protocupressinoxylon sp. A nov., the small scale-like leaves are Cupressinocladus valdensis (Seward) Seward and the small male cones Classostrobus sp. Alvin, Spicer and Watson. The tree is a source of Classopollis Pflug pollen so widespread in the Jurassic. A reconstruction of this Purbeck tree, based on evidence from fossil remains, is presented. The trees were monopodial with low branches and shallow spreading roots and formed fairly dense, closed forests. A few other conifer species were also present but much less abundant and cycadophytes (Bennettitales) are also represented by their silicified stems. The miospore assemblage from the palaeosols is dominated by Classopollis pollen (70% of samples), but also represents a rather poor flora of filicalean and lycopsid plants. Comparison with modern tree-ring data from semi-arid regions suggests a Mediterranean-type of climate for the Purbeck with warm, wet winters and hot, dry summers. The markedly seasonal nature of the climate is supported by sedimentary and faunal evidence such as ephemeral lake sediments containing both a freshwater fauna and flora plus evaporites. Modern analogues to the Purbeck environment have been found in the Mediterranean areas of the southern parts of Australia. The environment of the Callitris forests of Rottnest Island, Western Australia, appears remarkably similar to that of the~Purbeck forests. This type of seasonal, semi-arid climate during the Upper Jurassic accounts for the paradoxical association of evaporites with well developed forest vegetation. It contrasts with the widely held view, that the Jurassic climate was warm and equable. The reconstruction of the Purbeck trees and forest environment may serve as a model for other Upper Jurassic and Lower Cretaceous vegetation.

Francis, J.E. 1983b. The dominant conifer of the Jurassic Purbeck Formation, England. Palaeontology, 26, 277-294. Abstract: Fossil trees are preserved in situ in fossil soils in the Lower Purbeck (Upper Jurassic) strata of Dorset. Silicified tree stumps, still rooted in the soils, stand erect and protrude into the overlying limestones. Numerous trunks and branches lie on the soils, which also contain conifer shoots. The forests were dominated by one kind of conifer with wood, named here as Protocupressinoxylon purbeckensis sp. nov., foliage belonging to the species Cupressinocladus valdensis (Seward) Seward and with male cones yielding Classopollis pollen. A reconstruction of the anatomy and habit of the tree is given. The Lower Purbeck palaeoclimate is discussed using the evidence of tree growth rings and the character of the associated sediments.

Francis, J.E. 1984. The seasonal environment of the Purbeck (Upper Jurassic) fossil forests. Palaeogeography, Palaeoclimatology, Palaeoecology, 48, 285-307. Abstract: In the basal Purbeck Formation of Dorset a paradoxical association of evaporites and fossil forest vegetation is found, representing well-developed gymnosperm forests which grew on the borders of the shallow, hypersaline Purbeck lagoon which covered southern England during the late Jurassic. The dominant tree was a cheirolepidiaceous conifer which appears from its morphology to have been adapted to growing in a semi-arid environment. The narrow and variable growth rings of the trees indicate that conditions were marginal for tree growth and highly irregular from year to year. Comparison with modern tree-ring data suggests that the Purbeck climate was of Mediterranean type, with warm wet winters when the trees were able to grow but with hot, arid summers suitable for the formation of evaporites. The seasonal nature of the climate is also reflected in adjacent sediments, including a clay containing both fresh-water fossils and evaporites, calcrete crusts in the palaeosols, the nature of the silicification and the presence of seasonal crustaceans in finely laminated shales. Analogous modern environments for both the forests and the seasonal lagoonal sediments can be found in the Mediterranean-type climatic regions of South Australia. This evidence shows that within the "equable" Jurassic climate marked seasonal variations affected the whole environment. The seasonal nature of this climate supports recent palaeoclimatic models which propose that such a climate prevailed along mid-latitude continental margins during the Mesozoic.

Francis, J. E. 1986. The Calcareous Paleosols of the Basal Purbeck Formation (Upper Jurassic) Southern England. p. 112-138 in: Wright, V.P. (Ed.) Paleosols: Their Recognition and Interpretation. Blackwell, Oxford. ISBN 0-632-01336-2. By Dr. Jane Francis of Leeds University. Summary: Rendzina paleosols are preserved within a sequence of marginal continental deposits of algal stromatolitic and pelletoid limestones, constituting the basal part of the Lower Purbeck Formation in Dorset. The Great Dirt Bed is the most well-developed paleosol exhibiting a characteristically simple A/C rendzina profile, consisting of a dark organic-rich horizon overlying limestone bedrock. The main component of the matrix of the A-horizon is decomposed plant debris. There is little evidence of the activity of soil organisms and a notable absence of a pelletoid moder fabric, the faecal pellet textures typical of modern rendzinas. The upper O-horizon of undecomposed plant litter is also lost. This soil supported a conifer forest of slow-growing shallow rooted trees, now preserved in situ as silicified tree trunks and carbonized roots. Pebbles derived from the underlying limestone are incorporated in the soil matrix. Some consist of blackened sediment derived from a desiccated and fractured organic-rich deposit previously formed on the margins of the adjacent lagoon. The semi-arid, seasonal Purbeck climate promoted the formation of laminated and mottled deposits of secondary carbonate or calcrete, present as micritized bedrock, laminar rinds and cement around pebbles. This was itself brecciated by the soil processes and probably also by the mechanical action of the tree roots, then to become incorporated into the solum as pebbles. The Lower and Basal Dirt Beds are immature forms of rendzinas, with similar simple profiles of organic-rich layers with high carbonate content, overlying marl and devoid of large pebbles. The Lower Dirt Bed also supported a forest of conifers and cycadophytes. Each paleosol is capped by algal limestone, which originated as algal-bound sediment formed when rising saline lagoon water successively inundated the forests. This covered the tree stumps and the top of each soil with a protective layer of sediment, ensuring the rather exceptional preservation of these paleosols with in situ tree stumps. [Key paper on the Basal Purbeck Dirt Beds of Lulworth and Portland.]
..
Gale, A.S. and Kennedy, W.J. 2002. Introduction [to the Chalk], pp. 1-26 in: Smith, A.B. and Batten, D.J. 2002. Fossils of the Chalk. Palaeontological Association, Field Guides to Fossils: Number 2, Second Edition, revised and enlarged. The Palaeontological Association, London. 374 pp. ISBN 0 901702 78 1. Price £14 paperback.

Gale, A.S., Smith, A.B., Monks, N.E.A., Young, J.A., Howard, A., Wray, D.S. and Huggett, J.M. 2000. Marine biodiversity through the Late Cenomanian-Early Turonian: palaeoceanographic controls and sequence stratigraphic biases. Journal of the Geological Society, 157, 745-757. [Not on the Lulworth area, but useful for broad palaeoceanography and also for a list of recent references on the Chalk, including many by Gale.]

Gale, A.S., Young, J.R., Shackleton, N.J., Crowhurst, S.J. and Wray, D.S. 1999. Orbital tuning of Cenomanian Marly Chalk Successions, towards a Milankovitch Time Scale for the Late Cretaceous. Philosophical Transactions of the Royal Society, London, A (1999), 357, pp. 1815-1829.
Outcrops of Cenomanian marly chalks in the Crimea (Ukraine) and SE England (UK), 2600 km apart, display conspicuous decimetre–scale rhythmicity and can be correlated by using 12 biostratigraphical events. Closely spaced samples from the two sections were used to generate long time–series of digitally captured grey–scale reflectance data. Spectral analysis of these data demonstrates that if the rhythmicity is assumed to be driven by precession (bedding cycles; mode at 20 ka), it is seen to be modulated by the short eccentricity cycle (100 ka bundles). The latter signal is expressed in the sediments by the occurrence of dark marls at precession minima occurring at eccentricity maxima. Although identified in the spectra, tilt (38 ka) and the long eccentricity cycle (400 ka) are not strongly expressed. Comparison of age modelled, unfiltered grey–scale data between the two sections reveals strikingly similar patterns, and enables the identification of a 80 ka hiatus in the UK chalks.
[This paper is not on the subject of the Isle of Wight or of Dorset or Devon, but is very relevant to any study of the Cenomanian of those regions.]


..
Garden , I.R. 1987. The Provenence of Upper Jurassic and Lower Cretaceous Coarse Grained Detritus in Southern Britain and Normandy. Unpublished Ph.D. Thesis. Department of Geology, University of Southampton. One volume of 410 pages plus 50 pages of Appendices. 63 monochrome plates. September, 1987. By Ian Ross Garden (supervisor - IMW). Abstract: The provenance of coarse-grained detritus from the Upper Jurassic Corallian Group and Lydite Beds and Lower Cretaceous Purbeck Formation, Spilsby Sandstone Formation, Wealden Group, Claxby Ironstone Formation, Lower Greensand Group and Gault Clay Formation of southern Britain and Normandy (northern France) has been studied. The coarse-grained detrital suites contain extrabasinal phenoclasts derived from Palaeozoic and Precambrian massifs, and Jurassic and Cretaceous clasts from intrabasinal highs. The former assemblage is dominated by chert derived from Carboniferous limestone and quartz. Sandstones, radiolarian cherts and tourmalinites are locally abundant. The intrabasinal detritus is composed principally of chert, phosphorite and ironstone...Progressive changes in phenoclast suites provide a means for studying both local variations associated with uplift of intrabasinal structures and regional variations associated with basin development...Local variations in the intrabasinal pebbles suites of Dorset provide evidence of major fault-associated uplift of the South Dorset High during earliest Cretaceous times. Post-faulting subsidence resulted in marine onlap and further erosion of the structure. The South Dorset High is structurally similar to other fault-associated highs in the Wessex and Paris Basins, and it is probable that they have undergone extensive Early Cretaceous uplift in conjunction with basin rifting... The Upper Jurassic and Lower Cretaceous phenoclast suites of southern Britain and Normandy are separable into three stratigraphical assemblages. The oldest assemblage, Oxfordian to Early Berriasian in age, is dominated by chert derived from Carboniferous limestones. The two younger assemblages (Late Berriasian to Barremian and Aptian to Middle Albian) are distinguished by a generally higher proportion of quartz. The Aptian to Middle Albian phenoclast assemblage is separable into two subassemblages (Aptian, and Lower to Middle Albian) and the latter shows lateral changes which enable it to be subdivided into three geographical provinces and five subprovinces... In the Wessex Basin, a change from chert-dominated to quartz-dominated phenoclast suites occcurred at the beginning of the Cretaceous System. This resulted from uplift and erosion of the marginal massifs adjacent to the rifting basin. On the East Midland Shelf, however, modifications in the detrital suites did not occur until mid-Cretaceous times. The delayed change was caused by limited uplift of the adjacent massifs during Early Cretaceous times and reworking of slightly older pebble beds on the shelf. The marginal highs were then uplifted and eroded during the mid-Cretaceous phase of thermal subsidence in the Southern North Sea Basin. [End of Author's Abstract]

Notes: See Appendix 1, page x etc. for percentage composition of Wealden pebble beds of the Lulworth area. Eg. Lulworth Cove - decreasing abundance - (for -3.5 phi) - opaque quartz - 28, radiolarian chert - 25, quartz plus tourmaline - 24, translucent quartz - 13, fibrous quartz - 10. Similar information given for two size fractions at Durdle Door, Mupe Bay and Worbarrow Bay. Data also for the Gault in this area. Descriptions are given of reworked Portland and Purbeck detritus in the Wealden, Lower Greensand and Gault of Dorset and the Isle of Wight.
..
Geology Holiday Guide . 1995. Lulworth Cove Area. [An excellent, clearly illustrated glossy colour brochure. It is currently available, often in the shops at Lulworth Cove, and is highly recommended. It is suitable for beginners and first visitors to the area.]
.
Hancock , J.M. and Kauffman E.G. 1979. The great transgressions of the Late Cretaceous. Journal of the Geological Society, London, 136, 175-186.
.
Heathcote , M.F. 1906. Lulworth and its Neighbourhood. Wykeham Press, Winchester.
.
Hesselbo , S.P. 1988. Sequence boundaries in the basal Wealden Beds ( Lower Cretaceous; Wessex Basin) at Mupe Bay, Dorset. B.S.R.G. - British Sedimentological Research Group, 1988, Cambridge, no page numbers. [Two erosion surfaces are angular unconformities - one is the palaeo-oil seep - fluvial above]

Hesselbo, S.P. and Allen, P.A. 1991. Major erosion surfaces in the basal Wealden Beds, Lower Cretaceous south Dorset. Journal of the Geological Society, London, 148, (1) 105–113. By Stephen P. Hesselbo and Phillip A. Allen, Department of Earth Sciences, University of Oxford, Parks Road, Oxford, OX1 3PR UK. Abstract: The transition from evaporitic and lagoonal Purbeck Beds into the fluviatile basal Wealden Beds (Ryazanian-Valanginian) has in the past been interpreted as a continuous regressive succession. Mupe Bay and Bacon Hole, in south Dorset, are the only localities in the Wessex Basin of southern England at which the transition strata are well exposed and not extensively faulted. On the basis of facies analysis the lowermost Wealden Beds are interpreted as a regressive-transgressive-regressive package. Environments fluctuated between lagoon, inner-lagoonal shoreline and fluvial flood plain. The overlying succession is remarkable for the presence of two major erosion surfaces which, based on field geometries and fades relationships, are interpreted as unconformities. The lower unconformity is overlain at Mupe Bay by sediments of lagoonal or lacustrine origin. The upper unconformity is expressed as the celebrated Mupe Bay palaeo-oilseep, an oil-cemented conglomeratic sand, overlain by a thick succession of fluvial sediments. A level near the basal sand and the two erosion surfaces are treated as candidate sequence boundaries (WBI-WB3), with the thin intervening ?lagoonal deposits representing peaks of transgression. The pattern of one minor (conformable) sequence boundary followed by two major (unconformable) sequence boundaries bears a strong resemblance to the Early Cretaceous sequence stratigraphy suggested in recent 'global cycle charts'. However, biostratigraphical calibration of the sections is currently inadequate to allow close correlation with candidate sequence boundaries in other areas. [Comments: They discussed the origin of the conglomeratic oil sand at Mupe Bay. They recognised unconformities and have considered these as candidates for major subdivisions within the Wealden. Two major erosion surfaces at Mupe Bay, one the celebrated oil sand channel, are interpreted as unconformities. These authors attempt to establish a sequence correlated with Early Cretaceous sequence stratigraphy suggested in recent global cycle charts. The authors also comment, that subsidence histories and stratal geometries show that the main extensional activity on the fault system took place in early Jurassic and late Jurassic/early Cretaceous times and that the faults are probably active throughout deposition of the Purbeck and Wealden Beds. They record soft sediment deformation at Mupe Bay.]
.
House , M.R. 1965. Chalk solution pipes. Proceedings of the Dorset Natural History and Archaeological Society, vol. 86, pp. 39,40.

House, M.R. 1996. Dorset Doline: Part 3, Eocene pockets and gravel pipes in the Chalk of St. Oswald's Bay. Proceedings of the Dorset Natural History and Archaeological Society, for 1995, vol. 117, 109-116.

House, M.R. 1989. Geology of the Dorset Coast. Geologists' Association Guide, 169pp, 39 text-figs and 34 monochrome plates. September 1989. Paper-back. ISBN 0 7073 0485 7.

House, M.R. 1993. Geology of the Dorset Coast. Geologists' Association Guide No. 22. 2nd edition, 164pp., 43 text-figs (mostly cliff diagrams and maps) and 32 plates, some in colour. Paper-back. ISBN 0 7073 0485 7. Extract from Preface: "This guide aims to provide a general introduction to what may may be seen and where. Emphasis is placed on the localities and the precise discrimination of the stratigraphic successions. It is hoped that in this way new observations can be better integrated with earlier work and thus form a more scientific basis for individual study, thought and interpretation and argument. Most emphasis is placed on the Jurassic rocks because these are such an international standard. Rather less detail is given on the Cretaceous and Tertiary rocks because these rocks are as well or better seen elsewhere, and the Dorset Chalk cliffs, being mostly vertical, are also dangerous. In any case, with such a wealth of geology to describe, some selection has been essential. The introductory sections on Sedimentology and Palaeontology have been added by request to introduce specialist terms to the general reader. "
.
Kinghorn , R.F., Selley, R.C. and Stoneley, R. 1994. The Mupe Bay Oil Seep Demythologised. Marine and Petroleum Geology, 11, (1), p 124-125. Discussion of paper by Miles et al. . As previously suggested, geochemical differences between the clasts and matrix can be attributed to different stages of maturation of the source, hence two distinct episodes of oil migration, before and after formation of the conglomerate. The sand clasts would not have survived transportation unless previously saturated by oil. Authors' reply p. 125-126.
.
Houghton , H. 1972. Operation Portland: the Autobiography of a Spy. Rupert Hart-Davis, London. 164pp. [This includes an account of landing of Russian spies at Lulworth Cove in about 1960.]
..
House , M.R. 1965. Chalk solution pipes. Proceedings of the Dorset Natural History and Archaeological Society, vol. 86, pp. 39,40.

House, M.R. 1968. Purbeckian calcareous algae. In Dorset Natural History Reports - 1967 - Geology. Proceedings of Dorset Natural History and Archaeological Society for 1967. vol. 89, p.41-45. [By the late Professor Michael R. House. Not on Lulworth Cove, but on the stromatolite horizon of Perryfield Quarry, Portland. The equivalent bed occurs in the Soft Cockle Member at Lulworth Cove.]

House , M.R. 1969. The Dorset Coast from Poole to the Chesil Beach. 2nd Edition, Geologists' Association Guides, 22, 32pp. By the late Professor Michael House.

House, M.R. 1993 (and earlier edition in 1989)- Geology of the Dorset Coast. Geologists Association Guide No. 22. 2nd edition, 164 pages plus plates. ISBN 0 7073 0485 7.

House, M.R. 1996. Dorset Doline: Part 3, Eocene pockets and gravel pipes in the Chalk of St. Oswald's Bay. Proceedings of the Dorset Natural History and Archaeological Society, for 1995, vol. 117, 109-116.

[Example extract from the Introduction]
This contribution concerns the large pockets of Tertiary material within the Chalk between Hambury Tout and Man-o'-War Head west of Lulworth Cove. The vast majority of solution subsidence structures, or dolines, in Dorset occur close to the boundary between the Chalk and the overlying Tertiary deposits. It would be expected that these would show well along the coast, and those at the southern end of Studland Bay, where the unconformity between the Chalk and the lowest Tertiary Beds is well seen, have been much commented upon in the literature (see Arkell 1947, p. 221,2). Elsewhere the actual boundary does not crop out along the coast, but in the area between Durdle Door and Dungy Head, especially between Man-o'-War Head and below Hambury Tout, remarkable structures are seen in the cliffs of chalk which here reach almost 120 m in height (Figure 1A,B, 2).
The outcrop of the base of the Tertiary here runs inland parallel with the cliffs, but some 300 m inland and to the north (see map in House 1993, p.100). Noticeable in the cliffs are large pockets of blue clay, and solution holes often filled with rudites in a red matrix. For convenience of reference these outcrops have been given letters (Figure 1B). One of the photographs given here (Figure lA) was taken from the eastern end of the long reef of Purbeck Beds off Man-o'-War Head which is known as "The Man-o'-War". Another (Figure 2) was taken from the sea between and offshore of Norman Rock and Pinion Rock.
Despite the popularity of this coastline, with well over a million visitors a year, many of them geologists, references to the doline structures is minimal, and there is no reference to the large pockets of blue clay at all. In the Memoir Arkell (1947, p. 227,8) wrote about the structures as follows: "The cliff under Hambury Tout, - mile west of Lulworth Cove, shows large solution pipes in the chalk, filled with rusty sands and ground-up flints, and in places the wider pipes (e.g., Red Hole) contain in addition masses of grey loamy sand. It is not clear whether these pipes were formed before the Chalk was tilted into a vertical position and have been tilted with it, or whether they post-date the folding. If the deepest ones started from the top of the present hill and the filling is presumed to be Pliocene, they must have penetrated at least 400 feet; if, as is more probable, the filling is Eocene and they were started from the top of the Chalk, probably as the fold began to rise, they must have penetrated at least 600 feet." The first sentence gives the only published description of these large structures. The position of Red Hole deserves comment. The Ordnance Surface six inch to the mile maps of the end of the last century engraved "Red Hole" as immediately east of the boundary fence which reaches the cliff top above the western end of St. Oswald's Bay (Figure 1) where there is disturbed ground above the position of Outcrop A, probably more recently modified by temporary military trenches. Current 1:10,000 maps place Red Hole rather further to the east. Yet Rowe (1901, p1.2) has a photograph of Red Hole taken from beach level and showing the lower cliff there on the east side of Man-o'-War Head illustrating the F4 fault and suggesting Red Hole is a either a sea cave (none of which are now red coloured) or a pocket a little way up the cliff which is now overgrown or lost by erosion. Mottram (1973 p.23), on the other hand, after commenting briefly on the red dolines remarks 'there are at least three Red Holes.' [continues]

House, M. R. 2000. Dorset geological notes: Geological Survey maps. Proceedings of the Dorset Natural History and Archaeological Society, 122, 177-178. Extract - Geological Survey Map part of Dorset geological notes: "Two new editions of coastal BGS 1:50,000 maps were published in 2000, but are still (early 2001) only available as flat sheets. These are the West Fleet and Weymouth Sheet (341 and part of 342) and the Swanage Sheet (342 (east) and 343). Considerable detail is included including extensive cross sections, structure maps and maps showing offshore seabed sediment distribution. One general problem is that the maps now show very much more detail than former editions, detail which is perhaps more appropriate to the 1:25,000 or 1:10,000 scale. Formerly it was easily possible to elucidate overall structural and distributional patterns, but now member and subdivision colouring is so diverse that this is not possible to do at a glance. Furthermore a complex stratigraphic terminology is introduced; the Chalk, for example is now divided into seven Formations. The Corallian Beds (given as 80 - 110m in thickness) are regarded as the Corallian Group and divided into five formations whilst the Kimmeridge Clay (given as up to 245m) and almost certainly of very longer duration, is regarded as a single Formation: this gives curious deference to differences in a largely carbonate succession (the Corallian) as opposed to equally diverse differences in a largely argillite succession (the Kimmeridge Clay). Both should be treated equally and, in the writer's view, Formation is appropriate to both. The Kimmeridge Clay, in addition, is likely to have been the longer in duration. Some specific errors are mentioned below. ...West Fleet and Weymouth Sheet. Thomas Webster made some of the best early drawings of this coast which were eventually published in 18818 in Englefield's Picturesque Beauties of the Isle of Wight. Plate 45 of that work shows how the Portland Beds of Durdle Door pass westward to form the offshore rocks of The Bull and The Calf, many will have swum out, as has the writer to check this. Not so the BGS, and these are mapped as Chalk Group on the map. Such an error gives little confidence. In our Proceedings (Vol. 71, 175-183) Mottram showed by detailed excavation and full report how the Gault was not cut out at Moigns Down Barn and to the ESE: this evidence is ignored here. The remarkable discovery of outcropping Upper Greensand 200m WNW of Greenhill, near Sutton Poyntz, reported in our Proceedings (Vol. 91, 39) was missed and is mapped as Chalk. Missed also is the small fault cutting the Tufa west of Chalbury Camp. These are not matters of opinion. There has been a traditional practice to show where a boundary is uncertain with a dotted line and keeping only a full line only for certainty. In the Weymouth lowlands everything is shown as certain with great prejudice to the truth. The welcome attempt to map the Forest Marble shell beds suffers here. The introduction of so many faults in the Sutton Poyntz area and the Ringstead area, contrary to earlier mapping, will need careful justification. This type of justification is curiously absent from the published Technical Reports which give details on the mapped areas.... Swanage Sheet. The remarkable contribution here is the detailed subdivision and mapping of the early Tertiary deposits. The main Chalk ridge from Lulworth to Old Harry Rocks and Ballard Down shows dip faults at Arish Mell and south of Studland but otherwise does not invoke faulting to explain twists along the ridge. The Cretaceous/Tertiary boundary south of Studland is mapped as faulted."
..
Hovenden , F., Monkton, H.W., Ord, W.T. and Woodward, A.S. 1910. Excursion to Swanage, Lulworth Cove and Bournemouth. Report by the Directors. Proceedings of the Geologists' Association, 21, 510-521.
.
Hyland , P. 1998.Isle of Purbeck. Discover Dorset Series. The Dovecote Press, Stanbridge, Wimborne, Dorset. 79 pp. ISBN 1 874336 58 X. [By Paul Hyland. Small, popular style, general guide book, not specifically geological but with some information on quarries etc. Interesting account with some very good illustrations. Was sold in 2001 at Lulworth Heritage Centre at £4.95p.]
..
Jefferies R.P.S. 1961 (although listed as 1962 in Jefferies, 1963). The palaeoecology of the Actinocamax plenus subzone (Lowest Turonian) in the Anglo-Paris Basin. Palaeontology 4 (4), 609-647. Abstract: The plenus Subzone often conforms to a standard succession of eight beds, numbered 1 to 8 in ascending order. The distribution of aragonitic fossils in the plenus Subzone was probably controlled more by preservation than ecology. Preservation was determined firstly by temperature and secondly by turbulence. In late subglobosus [ the old Holaster subglobosus Zone - upper part of the Cenomanian] times the distribution of macro- and microfauna was governed by depth of water, and the depth preferences of the various species of benthonic foraminifera were like those of their relatives in varians [the old Schloenbachia varians Zone -lower part of the Cenomanian] times. There was little faunal change at the beginning of Bed 1 times, despite extensive erosion. This indicates that the pre-Bed 1 shallowing, for which there is much lithological evidence, was accompanied by only a small rise in temperature. A sudden change at the beginning of Bed 2 times to a shallower-water type of fauna was due to a considerable rise in temperature which led also to the preservation of aragonitic fossils. The peculiarities of the fauna of Beds 4-6, including the presence of Actinocamax plenus and Oxytoma seminudum, suggest a moderate decrease in temperature with the appearance of species of Central European Russian affinities. This moderate fall in temperature is reflected in the microfauna. During the deposition of Beds 7 and 8 the temperature rose again slightly. On the basis of certain simplifying assumptions the temperature of deposition of Bed 1 was probably below 5-10° C., that of Beds 4-6 about 16.9° C. and that of Bed 2 considerably higher than 16.9° C. [end of abstract. This paper does not deal with Lulworth Cove or the adjacent Dorset area specifically. It particularly deals with a succession at Merstham, Surrey. It does reveal that much important macrofossil and microfossil faunal data has been obtained from the plenus marl and that major palaeoecological interpretations can be attempted.]

Jefferies, R.P.S., 1963. The stratigraphy of the Actinocamax plenus Subzone (Turonian) in the Anglo-Paris Basin. Proceedings of the Geologists' Association , 74 (1), 1-33. Abstract: In the central parts of the Anglo-Paris Basin the Actinocamax plenus Subzone of the Inoceramus labiatus Zone conforms more or less to a standard succession of eight beds, numbered I to 8 in ascending order, which differ from each other in fauna and lithology. There are important erosion surfaces beneath Beds I and 4 and less important ones also beneath Beds 2, 6 and 8. In the outer parts of the Anglo-Paris Basin the plenus Subzone is represented by a condensed succession or stratigraphical gap associated with an erosion surface homotaxial with those of the standard succession.. An isopach map of the plenus Subzone in England shows that the pattern of deposition was Turonian rather than Cenomanian and a study of the insoluble residue in the various beds suggests that at any one time the muddiest deposits were laid down in the quietest water. On the other hand a tendency for Chalk marl bands to overlie erosion surfaces seems to show that they were usually due to a fall in erosion base associated with increased turbulence of the bottom-water. The Black Band of Yorkshire and Lincolnshire is probably mainly post-plenus and is a stagnant-water deposit, current flow perhaps having been interrupted by irregularities in the sub-plenus erosion surface beneath. [end of abstract]. Some details are given of the plenus Marl at Durdle Door: " North-east corner of Durdle Cove at foot of cliff. Fig. 10. 30/805803. Despite great regional tectonic disturbance the plenus Subzone seems complete. Base Bed 1 abrupt. No 2b or 3a. Bed 8 consists of 8a, band c. Aragonitic fauna abundant in Bed 1 (highly exceptional) as well as in Beds 2-3 and 4-8. Characteristic fossils: Bed 1, large Ostrea vesicularis, Neithea quinquecostata; 2, Entolium membranaceum (c), Calliderma smithiae; 3, Metoicoceras geslinianum; 4, Actinocamax plenus, Oxytoma seminudum; 5, Sciponoceras sp., Metoicoceras gourdoni."
.
Kennedy W.J. 1970. A correlation of the uppermost Albian and the Cenomanian of south-west England. Proceedings of the Geologists' Association, London, 81, (4), 613-677. Abstract: In south-west England, the uppermost Albian and the Cenomanian show considerable lateral variation when compared with the Gault, Upper Greensand and Lower Chalk succession of south-east England. From Warminster as far south as Melbury Down, west of Salisbury, there is a continuous succession from Albian to Cenomanian, with some Cenomanian Upper Greensand. In the valley of the Stour, Cenomanian greensands have disappeared, and the top of the Upper Greensand is of Upper Albian Stoliczkaia dispar and Mortoniceras (Durnovarites) perinflatum Sub-zone age as far west as Evershot. A few kilometres south of Evershot, a quartzose sandstone, the Eggardon Grit, appears. At some localities, this grit yields Lower Cenomanian ammonites. The Eggardon Grit and the underlying Chert Beds appear just north of the line of the Hooke Valley, and thicken considerably in a south-westerly direction. These relationships can be interpreted as the result of a major north-west to south-east 'structure', the Mid-Dorset swell of Drummond (in Smith & Drummond, 1962). Westward, the top of the Upper Greensand is highly variable, with boulder beds, sandy limestones and phosphatic conglomerates, the latter yielding rich Lower Cenomanian ammonite faunas. Over most of south-west England the base of the Chalk is a phosphatic conglomerate known as the Chalk Basement Bed. This is diachronous. When traced south-westward, it yields phosphatised and unphosphatised faunas indicating progressively higher horizons in the Middle and Upper Cenomanian. Bed C, of Actinocamax plenus Marls, Metoicoceras gourdoni Zone age, the base of the Middle Chalk on the Devon Coast, is the obvious extension of this Basement Bed.
.

Lake, S.D. 1986. Brecciated pipes in the Broken Beds, Purbeck Limestone Formation. Proceedings of Dorset Natural History and Archaeological Society, 107 (for 1985), 191-192. By S.D. Lake, at the time, Department of Geological Sciences, University of Durham, South Road, Durham.
Abstract:
Previously unrecorded breccia pipes extend up from the underlying Broken Beds into the undisturbed sedimentary cover. These have been identified at Bacon Hole and Durdle Door in south Dorset. The likely cause for the formation of the Broken Beds is re-evaluated. The results imply both diagenetic and tectonic effects during the Tertiary uplift of the Isle of Wight/Purbeck monocline alonga former Mesozoic roll-over anticline. [end of abstract]

[some incomplete extracts follow:]

" ---- Recent fieldwork by the author led to the discovery of breccia pipes that extend, in some cases, at least 10 metres from the Broken Beds into the overlying Lower Purbeck sequence. Therefore these hypotheses listed by West (1960) must somehow explain this phenomena or alternative hypotheses put forward.

The occurrence of the breccia pipes is particularly well exhibited at Bacon Hole (SY842797) where the largest upstanding stack has a peculiar knoll at the top (Fig. 1). This is particularly well seen in Plate 1 of Arkell's (1947) Memoir. On close examination this knoll displays the typical limestone brecciation associated with the Broken Beds, yet lies at least 5m above the main Broken Beds horizon. Examination from the seaward (southern) side of the stack particularly well displays the upward extension from the main Broken Beds horizon. A small scale example is well displayed on the eastern side of the stack, the brecciation extends some 4m into the overlying "Cypris" Freestone Member (Fig.1). The width of both of these pipes is approximately 4m.

Durdle Door eastern promontory (SY807803) also displaysa similar feature. The bedding planes of the 'Cypris' Freestones show a hemispherical brecciated body at beach level between the beach and the promontory. This brecciated body bears remarkable similarity to the underying Broken Bed horizon yet lies some distance above it. The location and size of this brecciated body is interpreted as reflecting another breccia pipe and not a separate Broken Bed horizon, such as those identified at Worbarrow Tout by West (1975) and Ensom (1985). Clearly these breccia pipes are important in the evolution of the Broken Beds horizon.
[continues]
------
In the light of this work [previous papers by West] a further contribution can be made resulting from the observed breccia pipes and new structural evidence. The evolution of the Broken Beds can perhaps be envisaged as follows: Primary gypsum was intercolated with calcareous shale and pelletoidal limestones in the lowest portion of the Broken Beds, whilst ostracodal biosparites, intrasparites and pelletoidal limestones occurred towards the top of the Broken Beds unit (West, 1964, 1975). Increasing depth of burial of the unit resulted in dehydration of the gypsum to anhydrite. This undoubtedly occurred prior to the Eocene and the initiation of uplift. The depth of burial was probably less than 1500 m on based on known sedimentary thickness of the overlying units. This structural evidence is also in agreement with theoretical studies which demonstrate that dehydration of gypsum occurs at a temperature of 42 degrees centigrade. Similar consideration of the present day geothermal gradient (30 degrees C / Km) allows a minimal depth estimate of dehydration. Coincident with this increasing burial, calcitisation of the lower Purbeck evaporite sequence took place in response to decarboxylation of organic matter. The dehydration resulted in an approximately 38% volume decrease (Blatt et al., 1972) thus resulting in abnormal fluid pressures. Fluids were undoubtedly derived from the nearby algal limestones and clays. Locally the dirt beds (the Great Dirt Bed in particular) that lie at the base of the Broken Beds sequence may have acted partly as an impermeable layer preventing downward percolation of fluids. This combined with increasing hydrostatic pressure associated with burial may have caused the pressured fluids to have outflow diapirically or resulted in hydrofracturing into the overlying 'Cypris' Freestones Member prior to flexuring.

[continues with text]

[See also the Fig 1 - a diagram of a breccia pipe in an offshore Mupe Rock at Bacon Hole.]

[Reference and - END OF ARTICLE]

Go back to top


.
George Martin Lees, Military Cross, DFC, FRS, Royal Flying Corps, Assistant Political Officer in Southern Kurdistan, Advisor to Sheik Mahmoud, Royal School of Mines, Chief Geologist of the Anglo Persian Oil Company (i.e. BP). After success in Persia he initiated oil exploration in the UK. See Wikipedia for more information about this remarkable man. (also washed away in a river and survived by using his pith helmet as a float; also survived a plane crash, and escaped on horseback from a major attack!)

Lees, G.M. 1935. [Gravity Slip Origin of Lulworth Crumples] in discussion of a paper by: Harrison, J.V. and Falcon, N.L. Abstracts of the Proceedings of the Geological Society, no. 1299, p. 110.

Lees, G.M. 1936. [Gravity Slip Origin of Lulworth Crumples] in: Quarterly Journal of the Geological Society, vol. 92, pp. 100-101.

Lees , G.M. and Cox, P.T. 1937. The geological basis of the present search for oil in Great Britain by the D'Arcy Exploration Company, Ltd. Quarterly Journal of the Geological Society, 93, 156-194. [See particularly pp 163-167. Wealden oil sands of Dungy Head and Mupe Bay. Oil residues in the Purbeck at Mupe Bay, Lulworth Cove and Durdle Door. Plates 11 and 12 are labelled photographs of Lulworth Cove and of Durdle Door with oil indications marked. Note that the supposed oil sand on the eastern side of the cove is not oil but carbonaceous.]

Go back to top


..
Legg , R. 1989. Purbeck Island. 2nd Revised Edition (first published in 1972). Dorset Publishing Company at the Wincanton Press, Wincanton, Somerset. ISBN 0 948699 08 6. 230 pp. (Much useful historic and topographic and some geological information. Short sections on dinosaur footprints, quarries etc).

Legg, R. 1998. Lulworth Encyclopaedia. Dorset Publishing Company at the Wincanton Press National School. Wincanton, Somerset. 128pp, paperback. Price in 2001 - £1.99p. Covering the Lulworth Ranges and the Dorset coastal parishes of West Lulworth, East Lulworth, Tyneham, Steeple, East Holme and Coombe Keynes. [Historical and other information on specific localities in the Lulworth area. Not generally geological.]
.
Loader , J. and Loader, P. 1932 (reprinted 1984). Tales of Lulworth in Olden Days. Written by Misses J. and P. Loader. Contributed by Members of the Women's Institute, Lulworth. Deer Park Press, Richmond, Surrey, 43pp.
..
Lulworth Estate . Undated. Lulworth Walks No. 5. Lulworth Cove and Iron Age Hill-Fort. Colour brochure, 50 pence in 2001.

Lulworth Estate. Undated. Lulworth Walks No. 6. Lulworth Cove to Durdle Door, Bat's Head and White Nothe. Colour brochure, 50 pence in 2001.[Some other walking guides in this series relate to the area near Lulworth Castle.]

Lulworth Estate. Undated. A Guide to Lulworth Cove. 30 pence in 2001. [Colour map with information on tourist attractions of the coast.]
.
Lydekker , R. 1889. On certain chelonian remains from the Wealden and Purbeck. Quarterly Journal of the Geological Society, London, 45, 511-518.

Lydekker, R. and Boulenger, G.A. 1887. Notes on Chelonia from the Purbeck, Wealden and London Clay. Geological Magazine, (3), vol. 4, 270-275.
.
Martill , D.M. and Naish, D. 2001. Dinosaurs of the Isle of Wight. Palaeontological Association, Guides to Fossils: No. 10, Palaeontological Association, London, 433 pp. ISBN 0 901702 72 2. Edited by David M. Martill and Darren Naish, technical editing by David J. Batten, photography by Robert Loveridge, computer generated artwork by Stig Walsh, contributors - Stafford Howse, Stephen Hutt, Andrew R. Milner. Price for paperback in 2001 - £16. Address of editors: School of Earth and Environmental Sciences, The University of Portsmouth, Burnaby Road, Portsmouth, PO1 3QL, UK. Contents: Acknowledgements, Preface, Chapter 1 Introduction by David M. Martill, Darren Naish and Stephen Hut, Chapter 2 The Geology of the Isle of Wight by David M. Martill and Darren Naish, Chapter 3 The Global Significance of Isle of Wight Dinosaurs by David M. Martill and Darren Naish, Chapter 4 Taphonomy and Preservation by David M. Martill, Chapter 5 Ornithopod Dinosaurs by David M. Martill and Darren Naish, Chapter 6 Boneheaded and Horned Dinosaurs by David M. Martill and Darren Naish, Chapter 7 Armoured Dinosaurs by David M. Martill and Darren Naish, Chapter 8 Saurichian Dinosaurs 1: Sauropods by David M. Martill and Darren Naish, Chapter 9 Saurichian Dinosaurs 2: Theropods by David M. Martill, Stephen Hutt and Darren Naish, Chapter 10 Dinosaur Trace Fossils: Footprints, Coprolites and Gastroliths by David M. Martill and Darren Naish, Chapter 11 Pterosaurs by Stafford C.B. Howse, Andrew Milner and David M. Martill, Chapter 12 An Aid to the Easy Identification of the Commoner Wealden Dinosaur Bones by David M. Martill and Darren Naish. [Not on Lulworth Cove, but useful for understanding the Wealden of the Lulworth district by comparing it to the Wealden of the Isle of Wight which is described here. See Martill, D.M. and Naish, D. 2001. 2. The geology of the Isle of Wight. pp. 25-43 in the above publication.]

Martill, D.M. and Naish, D. 2001b. 2. The geology of the Isle of Wight. pp. 25-43 in: Martill , D.M. and Naish, D. 2001. Dinosaurs of the Isle of Wight. Palaeontological Association, Guides to Fossils: No. 10, Palaeontological Association, London, 433 pp. ISBN 0 901702 72 2. Edited by David M. Martill and Darren Naish.
.
May, V. 2008. Geomorphology of Dorset: a Review. Proceedings of the Dorset Natural History and Archaeological Society, 129, 2008, 149-162. By Professor Vincent May, Bournemouth University, Talbot Campus, Fern Barrow, Poole, BH12 5BB. [This paper discusses a wide range of topics including the origin of the Chesil Beach, the entrance of Poole Harbour, sand dunes of Studland, the Axe estuary, offshore ledges at Worbarrow Bay, lack of a submerged channel off Lulworth Cove, conservation and RIGS sites etc. It includes various reference, some of which are not well known and some of which are unpublished Ph.D theses of Bournemouth University (e.g. Cook, 2007 - Studland peninsula; Drayson 2005 - Weymouth Bay acoustic).
..
Melville , R.V. and Freshney, E.C. 1982. British Regional Geology: The Hampshire Basin and Adjoining Areas. British Geological Survey (formerly the Institute of Geological Sciences), London, Her Majesty's Stationery Office. 146 pp.
..
Mitchell , J.J. 1989. A History of Lulworth Cove and Churchfield House. Milbury Publications Ltd., Maidstone, Kent. 76 pp.
..
Morris , S. 2005. Two friends feared drowned after being Swept from rocks. By Steven Morris. The Guardian Newspaper, Saturday November 5. p. 13. "Two teenage boys were feared drowned last night [evening of Thursday, November 3, 2005] after being swept from rocks into the sea at a Dorset beauty spot... Matthew Myburgh, 16, and Charles Morrell, 15, both from West Lulworth, had clambered past danger signs on to rocks in 70mph winds at Lulworth Cove... A third boy, Richard Lawrence, 15, jumped into the sea to try to rescue his friends but could not reach them. He saved himself by grabbing a buoy and swam back to shore to raise the alarm. A search operation took place yesterday; watched by the boys' relatives and friends. More than 100 rescuers examined nooks and crannies in the rocky coast but the only trace of the pair was one of their shoes and a baseball cap found washed up a mile from where they disappeared... The three boys, close friends and pupils at the Purbeck school in Wareham, decided to go on to the rocks to fish or to watch the stormy sea on Thursday evening. Matthew and Charles, who were perched on a ledge, were caught by a wave and thrown into the water. At first, Richard, who was on a higher ledge, thought they were joking when they shouted for help, but when he realised what had happened he jumped into the water. He could still hear his friends shouting, but because it was dark he could not find them... It was estimated the boys could have survived for three hours in the water. The search continued all day yesterday, with rescuers hoping they might have made it to shore and be clinging on to the cliffs or sheltering in a rock hole. At one time more than 100 people including the coastguard, police, lifeboat crews and Royal Marines were involved. Relatives of the missing boys visited the spot yesterday. The mother of the surviving boy said: "He is very upset but bearing up quite well.".. A neighbour added: "You would always see the three lads together in the village. But why the hell they went there on a night like that, I just don't know." One resident, whose son is a friend of the boys, said: "They were just normal nice boys." A restaurant worker said: "Everybody knows everybody, so it has hit the community hard." Mark Rodaway, coastguard commander for southern England, said: "The waves were enormous, the biggest seas I have seen in years. The severe gales coupled with the high tide created a mix which made for treacherous and atrocious conditions. "... Warning signs at Lulworth Cove state that climbing is prohibited and it is "extremely dangerous" to climb or sit beneath the cliffs. Friends of the missing boys also joined in the search. One of them, Maria Osmond, said: "It is horrible, but you can't give up hope.".. Police last night took over the operation from the coastguard, indicating that the emergency services now believed it was unlikely the boys would be found alive. Police divers will search the bay today for their bodies." [end of article, with a small photograph of a lifeboat]
(There were several other media reports in national Newspapers and in the Bournemouth Daily Echo and Weymouth Daily Echo for 4 November 2005. Accounts are also in subsections of the Internet versions of these newpapers - entitled - This is Bournemouth and This is Weymouth. They contain similar information.)
.
Mortimore, R.N., Wood, C.J. and Gallois, R.W. 2001. British Upper Cretaceous Stratigraphy. Geological Conservation Review Series (GCR), Volume No. 23. Joint Nature Conservation Committee (JNCC), UK. 558 pp., illustrations, A4 Hardback, ISBN 1 86107 488 3. Chapter 1 and Chapter 3 are available free as pdf files online. Price for the thick book, in 2009, - 53 pounds sterling.
This volume provides a comprehensive explanation of the geology and the geological significance of 37 GCR sites across the British Isles from coastal cliffs to individual small chalk pits.
Summary:
Upper Cretaceous rocks, primarily Chalk, cover a vast area of England forming the Downs and Wolds as well as the spectacular chalk cliffs from Flamborough Head to south-east Devon. In south-east Devon and the Inner Hebrides of north-west Scotland, white chalk rests on greensands, calcareous sands and commercially important quartz sandstones. Scientific knowledge of these rocks is an essential part of planning construction projects, developing and protecting groundwater resources and utilising the materials such as flint, chalk and sands for industrial processes.
Historically, the fossils from the Chalk, such as the echinoid Micraster, have made major contributions to evolutionary studies. Fossils, combined with detailed analyses of the structure and sedimentology of the Chalk and associated rocks, continue to be a focus for developing new ideas in stratigraphy, modelling past climates and investigating biodiversity and mass extinctions.
Thirty-seven GCR sites across the British Isles are described and linked to numerous other sites to provide a comprehensive explanation of the geology and the geological significance of each GCR site. Individual sites vary from coastal cliffs, many kilometres long, to individual small chalk pits. Where possible, sites have been extensively re-investigated to provide the most up-to-date reviews.
..
Mottram , B. 1972. Some aspects of the evolution of parts of the Dorset coast. Proceedings of the Dorset Natural History and Archaeological Society, 94, 21-26.
..
Nowell , D.A.G. 1996. Faults in the Purbeck - Isle of Wight monocline. Proceedings of the Geologists' Association, 106, 145-150. Faults at Arish Mell and Corfe Castle in Dorset and at Freshwater Bay and Shide, Newport on the Isle of Wight cut the Purbeck - Isle of Wight monocline. Evidence for these hitherto unrecognised faults is based on outcrop displacement and differences in: (a) outcrop widths either side of the faults; (b) strike and dip of the strata; and (c) the direction of the axis of the monocline. These faults developed above offsets in large normal faults beneath the subsequent monocline and were active growth faults during deposition of the Chalk. During the later Alpine tectonic episode which formed the Purbeck - Isle of Wight monocline these faults were reactivated so displacing the boundary between the Chalk and the Reading Beds. The faults locally weakened the chalk ridge and allowed south to north drainage to develop through the ridge.

Nowell, D.A.G. 1997a. Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting. Proceedings of the Geologists' Association, 108, 257-268. Pre-Albian northwest-southeast faults have been inferred along the coast between Durdle Door and Worbarrow Tout. From the westward increase in the thickness of Wealden units between Mupe Bay and Lulworth Cove followed by the dramatic thinning across the cove it is suggested that these faults were synsedimentary growth faults during the early Cretaceous. Also the Wealden is shown to contain two main quartz grit bands, only the lower of which is seen in Lulworth Cove due to increasing westwards Albian erosion which mainly explains the westward thinning of the Wealden. These faults may have continued to be active throughout the rest of the Cretaceous. During the later Alpine formation of the Purbeck monocline, southward dipping faults also developed. Their alignment may have been controlled by the reactivated northwest-southeast faults. To the west of Lulworth Cove much of the succession between the Portland Stone and the Chalk is cut out by these east-west thrusts.

Nowell, D.A.G. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): reply. Proceedings of the Geologists' Association, 109, 239-240. This is a reply to a discussion of Nowell's 1997a paper by Jon Radley of Reading University. Radley, J.D. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): comment. Proceedings of the Geologists' Association, 109, 237-238.

Nowell, D.A.G. 1998b. The geology of Lulworth Cove, Dorset. Geology Today, 13, 207-210.

Nowell, D.A.G. 2000. The geology of Worbarrow, Dorset. Geology Today, Vol. 16 (2), 71-6.

Nowell, D.A.G. 2001. Southern Dorset remapped? Reviews. Circular of the Geologists' Association, No. 949 for December, 2001, p. 12. [Referring to this and the new sheet for Swanage (342 east and part of 343) and for Dorchester (328). Amongst other favourable points, the writer commented that: " These maps have completely revised stratigraphic units that more fully reflect the distribution of the different rock types and recognisable sequences within the sediments of southern Dorset that, across country, can be mapped in greater detail than was previously possible. The clearest changes are to the traditional lower, middle and upper divisions of the Chalk, which have been replaced by up to eight formations, while the Purbeck is divided into five members of the Durlston and Lulworth Formations. Another necessary change, even if it is slightly garish, is the effective use of red and grey tones to show the complex sand and clay variations within the Eocene sequence, which was deposited after the uplift and erosion of the Chalk.... These splendid maps can be thoroughly recommended to anyone who is interested in the picturesque and fascinating geology of southern Dorset. Flat or folded copies cost £9.95p. each and can be ordered from the Sales Desk, British Geological Survey, Nottingham, NG12 5GG (Tel. 0115-936 3241 Fax 0115-936 3488) or obtained by visiting the BGS London Information Office at the Natural History Museum (Tel. 020-7589-4090)." But see also House, 2000]
..
Owen H.G. 1971. Middle Albian stratigraphy in the Anglo-Paris basin. Bulletin of the British Museum, Natural History (Geology), Supplement, 8, 1-164.
..
Perkins , J.W. 1977. Geology Explained in Dorset. David and Charles, Newton Abbott, 224 pp. ISBN 0-7153-7319-6. [A good explanation of Dorset geology with well-labelled diagrams.]
.
Phillips W.J. 1964. The structures in the Jurassic and Cretaceous rocks on the Dorset coast between White Nothe and Mupe Bay. Proceedings of the Geologists' Association, London, 75, (4), 373-405. By W.J. Phillips, Department of Geology, University College of Wales, Aberystwyth. Abstract: The structures associated with the steep, northward inclined Portland and Purbeck Beds, and the nearly vertical or overturned Wealden Beds and Chalk, exposed on the Dorset coast between White Nothe and Mupe Bay, form the subject of an important paper by W. J. Arkell (1938). Arkell thought that the structures occurred on the steep north limb of a major monocline which was formed by lateral pressures from the south. In the present paper the minor structures in the Purbeck Beds are described in detail and it is shown that they can be related to the development of a fold formed by the increasing northward dip of the underlying massive Portland Beds. The direction of overturning of the minor folds indicates movement of the beds down the dip slope and not upward drag as postulated by Arkell. The formation of the sets of shear planes and faults recognised by Arkell in the Chalk is considered, and it is suggested that they can be divided into two genetic groups. The first group of structures formed during the closing of the syncline, while the second group brought about its modification by thrust displacements on southward inclined thrust planes and late faults. Arkell's conclusions concerning the causes of the reduction in the thickness of the incompetent Wealden Beds are summarised briefly, but by the construction of cross-sections of the main structure, it is demonstrated that the missing portions of the Purbeck and Wealden successions could have been displaced only by thrust movements on southward inclined major faults. A stage-by-stage synthesis of the development of the structures is presented and it is suggested that they were formed as the result of the accommodation of the blanket of largely unconsolidated sedimentary beds above a major thrust fault in the basement. At first a broad flexure developed and this became most pronounced in the highest division, the Chalk, because of the buckling and northward sliding of these beds off the rising land to the south. As the magnitude of the fault increased, successively higher beds fractured and eventually the fault extended to the surface and brought about the displacement and modification of the structures formed during the earlier phase of folding.
.
Prestwich , J. 1875. Notes on the phenomena of the Quaternary period in the Isle of Portland and around Weymouth. Quarterly Journal of the Geological Society, London, 31, 29-54. [Raised beach, landslides, beef and middle Purbeck detritus at Portland Bill, Chesil Beach, vertebrate remains in fissures, the Portland Mammaliferous Drift etc.]

Prestwich, J. 1892. The raised beaches and 'Head' or rubble-drift, of the south of England; their relation to the valley drifts and to the Glacial Period; and on a late post-Glacial submergence. Quarterly Journal of the Geological Society, London, 48, 263-343.
.
Pridham, L. 194?. The Dorset Coastline; from a personal and photographic point of view. Written by Dr. Llewellyn Pridham, M.R.C.S, L.R.C.P., R.N. (RETD). Photography by Edwin Kestin. 126pp. Longmans (Dorchester) Ltd., 4 Cornhill, Dorchester, Dorset, The Friary Press. A classic Dorset book with excellent monochrome photographs.

The Fountain Rock, east of White Nothe, is something of a Dorset secret, but it shows good horizontal Chalk at about the axis of the foresyncline, old photograph by Edwin Kestin in Llewellyn Pridam's book - The Dorset Coastline
.
Radley, J. D. . Derived fossils in the southern English Wealden (non-marine early Cretaceous): a review. Cretaceous Research, vol. 26, issue 4, pp. 657-664. By Dr. Jonathon D. Radley, Warwickshire Museum.
Abstract:
Derived fossils occur in all the principal facies associations of the southern English Wealden succession (non-marine early Cretaceous). They confirm the presence of Palaeozoic and early–mid Mesozoic source massifs surrounding the Weald and Wessex depocentres, fringed by scarps and intrabasinal highs of Jurassic strata. The derived macrofossil material is largely siliceous and phosphatic. It gains abundance in lake strandline gravels but also occurs as scattered reptilian gastroliths and among lagoonal shell concentrations. Calcareous fossils are abundant at one site, reflecting proximity to source. Jurassic dinoflagellate cysts are widespread among finer-grained facies.
.
Robinson , C.E. 1882. A Royal Warren or Picturesque Rambles in the Isle of Purbeck. The Etchings by Alfred Dawson. London. The Typographical Etching Company, 23 Farringdon Street. 186pp.
..
Rowe , A.W. and Sherborn, C.D. 1900. The zones of the White Chalk of the English coast 1. Proceedings of the Geologists' Association, London, 16, 289-368.

Rowe, A. W. and Sherborn, C.D. 1902. (check 1901?) The zones of the White Chalk of the English coast. 2. Dorset. The maps and cliff sections by C. D. Sherborn. The White Chalk of the Dorset Coast. From White Nothe to Worbarrow Bay, and from Ballard Hole to Studland Bay. Proceedings of the Geologists' Association, London, 17, 1-76. [Dr Arthur W. Rowe and C. Davies Sherborn. An important classic with good maps and diagrams. It does not, however, show the F4 fault in the Bindon Hill cliff. Very good for details of fossil occurrences and zones. Photographs of the cliffs by Professor Armstrong are of very good quality.]
.
Schnyder , J., Baudin, F. and Deconinck, J-F. 2005. A possible tsunami deposit around the Jurassic–Cretaceous boundary in the Boulonnais area (northern France). Sedimentary Geology, 177, Issues 3-4, 209-227. By Johann Schnyder, François Baudin and Jean-François Deconinck.
Abstract: An unusual succession of facies locally deposited around the Jurassic–Cretaceous boundary in the Boulonnais (northern France) is attributed to a tsunami event by comparison with recent tsunami deposits. This sedimentary succession includes basal erosion with reworked lithified blocks, soft-sediment deformations, an erosional conglomerate overlain by wood fragments and clays containing continental and marine fossils in one setting and conglomerate with mixed fauna in an other setting. The tsunami probably affected the coast of the Boulonnais area of the London–Brabant Massif. The origin of the event is unknown. It was most probably triggered by an earthquake, but other origins such as volcanic eruptions, a giant landslide, or even the impact of an extraterrestrial bolide into the ocean may also be considered. [Position within the Purbeck sequence is not certain but it is near the J/K boundary and some evaporites are present. Thus by comparision with Dorset it is likely to be Lower (perhaps to Middle) Purbeck and not equivalent to the Stair Hole liquifaction bed (Upper Purbeck).]

Schnyder, J., Ruffell, Deconinck, J-F and Baudin, F. 2006. Conjunctive use of spectral gamma-ray logs and clay mineralogy in defining late Jurassic–early Cretaceous palaeoclimate change (Dorset, U.K.). By Johann Schnyder (Universite Paris), Alistair Ruffell (Queen's University, Belfast), Jean-Francois Deconinck (Universite de Bourgogne) and Francois Baudin (Universite Paris). Palaeogeography, Palaeoclimatology, Palaeoecology, 229, (4), Jan 2006, 303-320. Available online from Elsevier - Science Direct. Abstract: Detrital clay mineralogy is controlled by weathered source rock, climate, transport and deposition that in turn influence the spectral gamma-ray (SGR) response of resultant sediments. Whilst a palaeoclimate signal in clay mineralogy has been established in some ancient successions, the SGR response remains contentious, largely because the data sets have yet to be collected at the same or appropriate vertical scales to allow comparison. In addition, the influence of organic matter on SGR is not always considered. Here, we present clay mineralogical, total organic carbon (TOC) and SGR analyses from the late Jurassic and early Cretaceous of the Wessex Basin, a period of previously documented palaeoclimate change. The aim of this paper is to estimate the sensitivity of SGR as palaeoclimatic tool, SGR and clay mineral data having been collected at the same sample points, making this one of the most rigorous comparison of clay mineral and SGR to date. Overall, the correlation between high thorium/potassium or thorium/uranium and kaolinite associated with a well-established palaeoclimate change shows that elevated thorium may be used as a proxy for humid palaeoweathering, as suggested by few previous studies. [end of abstract]. Keywords: spectral gamma ray; clay; clay mineralogy; palaeoclimate; Purbeck facies; Jurassic; Cretaceous; Jurassic–Cretaceous boundary; thorium; Dorset; England.
..
Sellwood , B.W., Durkin, M.K. and Kennedy, W. J. 1970. Field meeting on the Jurassic and Cretaceous rocks of Wessex. Proceedings of the Geologists' Association, 81, (4), 715-732. By Professor Bruce Sellwood of Reading University and co-authors. [This is a well-illustrated and informative paper, notable for a set of excellent diagrams of trace-fossils]. Information on Lulworth Cove is limited. See the following extract: "Tuesday, 8 April, 1969. Upper Jurassic and Cretaceous of Lulworth Cove and Durdle Door (SY 830797-805803). Features of this area have been described by West, Shearman & Pugh (1969), and no detailed description is therefore given here. The party left Axminster and drove to Lulworth, where they climbed to the ridge between Lulworth Cove and Stair Hole. From this vantage point the structure and stratigraphy of the area were outlined. The Portland and Purbeck Beds were examined in Stair Hole, after which the party walked to the east side of Lulworth Cove, climbed to the Fossil Forest, and examined in detail the Dirt Beds, Broken Beds, algal limestones and stromatolitic horizons of the Purbeck Beds. Returning to Lulworth, the party went to St. Ostwald's Bay, and examined the Portland Beds to Upper Chalk succession in both the eastern and western ends of the bay. The final exposure examined was the Upper Greensand and Lower Chalk west of Durdle Door. Members then climbed to the car-park above Durdle, to meet the coach. A vote of thanks to the Directors was proposed by Mr. H. I. Porter, and the party then returned to Weymouth.
.
Shinn, E.A. 1983. Tidal flat environment. By Eugene A. Shinn. Pp. 171-210 in: Scholle, P.A., Bebout, D.G. and Moore, C.H. 1983. Carbonate Depositional Environments. American Association of Petroleum Geologists, Tulsa, Oklahoma. 708 pp. [This does not refer to Lulworth Cove, but the description of tidal flat and other environments is relevant to the Purbeck Formation and the Portland Group of Lulworth Cove.]
..
Skelton , P.W. (editor) 2003. The Cretaceous World. The Open University and Cambridge University Press. 360pp. Edited by Peter W. Skelton. Authors Peter W. Skelton, Robert A. Spicer, Simon P. Kelly and Ian Gilmour. ISBN 0521 53843 2 paperback, ISBN 0521 83112 1 hardback. This publication forms part of an Open University Course, S369, The Geological Record of Environmental Change. Example extract from the first page, which is about the book in general: "The rich geological record of the Cretaceous Period reveals a world that experienced extreme climatic warmth and significantly higher global sea-levels than today. Elevated levels of atmospheric carbon dioxide have been implicated in these conditions. It thus provides a natural case study of the Earth in 'greenhouse' climatic mode, which this interdisciplinary textbook analyses from the perspective of Earth System Science. With mounting concerns over global warming today, an understanding of how the Earth system operates when in greenhouse mode is very relevant to studies of future climatic change. Part 1 (Chapters 1-5) surveys what the Cretaceous world was like, covering the evidence for the major changes in palaeogeography, sea-levels, life and climates that took place during the period, and especially the remarkable responses to climatic conditions of high-latitude vegetation and the shallow marine biota at low latitudes. Part 2 (Chapters 6-9) explores the interactions between the physical, chemical and biological processes, both within the Earth and at its surface, that together controlled conditions on the Cretaceous Earth, and highlights how they differed from those of our present world. Comparison is made between the global carbon cycles of then and now, with particular attention to the geological sources (especially volcanism) and sinks (organic carbon on land and carbonate plus organic carbon in the sea). Other biogeochemical cycles are also discussed. The results from computer modelling of climates are also critically reviewed. Part 3 (Chapters 10-13) investigates the infamous mass extinction that terminated the period, and its causation. Finally, a short Epilogue considers broader issues arising from this case study of the Cretaceous world..." [continues]. [This is a very good, very interesting and stimulating book and it is highly recommended - IMW]
..
Smith, A.B. and Batten, D.J. 2002. Fossils of the Chalk. Palaeontological Association, Field Guides to Fossils: Number 2, Second Edition, revised and enlarged. The Palaeontological Association, London. 374 pp. ISBN 0 901702 78 1. Price £14 paperback. Contents: Preface to the first edition; Preface to the second edition; 1. Introduction - A. S. Gale and W. J. Kennedy; 2. Sponges - R. Wood; 3. Corals - A. S. Gale; 4. Serpulids - A. S. Gale. 5. Brysozoans - P. D. Taylor; 6. Brachiopods - E. Owen; 7. Introduction to molluscs and bivalves - R.J. Cleevely and N. J. Morris; 8. Gastropods - R. J. Cleevely and N. J. Morris; 9. Ammonites - C. W. Wright and W. J. Kennedy; 10. Nautiloids - W. J. Kennedy; 11. Belemnites - P. Doyle; 12. Arthropods - S. F. Morris and J. S. H. Collins; 13. Echinoderms - A. B. Smith and C. W. Wright; 14. Fishes - A. E. Longbottom and C. Patterson; 15. Reptiles - A. C. Milner; References; Index.
Preface to Second Edition: Since the first edition of Fossils of the Chalk appeared 14 years ago a great deal of new information on the taxonomy of the fauna and the nature of the Chalk environment has been published, and refinements to the biostratigraphical and lithostratigraphical framework have been made. This new edition is consequently revised and enlarged to bring it up to date with current thinking. There is an expanded Introduction that outlines the depositional environment of Chalk sediment and a more detailed stratigraphical tramework. Three new chapters have been added, covering corals, serpulid worms and nautiloid molluscs, groups that were omitted trom the first edition. Other chapters from the original edition have been updated, some with new text-figures or plates, to take into account work published since 1987. There are now descriptions and illustrations of 434 species in 67 plates, providing even better coverage of the Chalk fauna. Andrew B. Smith, David J. Batten.
.
Smith, Steven. 2009. Nine-year-old boy who was buried by rocks at Lulworth Cove is discharged.
[This was a rock fall from about 10ft (3m.) above and not from the high Black Rocks sourc site high in the cliffs.]
The nine-year-old boy thought to have been seriously injured when he was buried under rocks was discharged from hospital yesterday, Coastguards said. He was completely covered by the falling rubble on Sunday as he played in the late summer sun at Lulworth Cove. Initially it was thought that the child had serious spinal injuries, but yesterday he was discharged from hospital, a Coastguard spokesman confirmed.

He said: "It's all round good news, if you consider the situation. It’s an unpredictable event of being in the wrong place at the wrong time; it had a very successful outcome." The child was thought to have been lying down at the time the rocks fell from 10ft above and shocked onlookers, including the boy’s father, raced to free the child from the rubble, which also struck an 11-year-old girl.

When Coastguards arrived, the child had already been freed from under the rocks and was airlifted to Dorset County Hospital in Dorchester, while the girl was taken via ambulance. She was released the same day. The incident happened on the eastern side of the cove at Black Rock. Coastguards said that cliff falls do not happen often at the cove, the last one being earlier this year, but nobody was nearby at the time.

Yesterday Lulworth Estate staff were at the cove assessing the scene. A spokesman said rock falls and land slips were rare, but warning signs were put up around coastal areas. Patrick Durnford, assistant to the Lulworth Estate general manager, said: “It is not known what may have triggered this particular slip, although this is being looked into. The incident is regrettable and we do hope that visitors will not be discouraged from enjoying the stunning and unspoilt coast around Lulworth Cove. "The estate is relieved to hear that both the children, particularly the boy, who was more seriously injured, are making a good recovery and our thoughts remain very much with them and their family."
..
Steers , J.A. 1946. The Coastline of England and Wales. Cambridge University Press, and 2nd Edition 1964.

Steers, J.A. 1960. The Coast of England and Wales in Pictures. Cambridge University Press. 146.

Steers, J.A. 1981. Coastal Features of England and Wales. The Meander Press, Cambridge.
.
Stewart , D.J., Ruffell, A., Wach, G. and Goldring, G. 1991. Lagoonal sedimentation and fluctuating salinities in the Vectis Formation (Wealden Group, Lower Cretaceous) of the Isle of Wight, southern England. Sedimentary Geology, 72, 117-134. Abstract: Sedimentation in the Shepherd's Chine Member of the Vectis Formation is characterised by a cyclicity of four principal facies on which a strong asymmetry has been imprinted by erosional events. The four lithofacies are: (1) very fine to fine sandstones; (2) heterolithic sand/silt and mudstones; (3) parallel-laminated (pinstripe) mudstones; and (4) black mudstones. The biota, principally associated with lithofacies 2 and 3 (as shelly partings and coquinas), can be grouped into five molluscan associations which range from freshwater to quasi-marine. These associations are poorly correlated with the lithofacies, but fluctuate within and between cycles. Salinity and storm frequency increase towards the top of the formation, heralding the main marine Aptian transgression. Lithofacies and biotas indicate deposition in a lagoon that was shallow and temporarily emergent. The cyclicity is thought to represent the more distal phases of the advance and retreat of deltaic sand bodies, derived from a westerly direction, into the lagoon. Major storm events broke the symmetry of the cycles. A deltaic facies, represented by the Barnes High Sandstone Member, is thought to be laterally linked, reworked deltaic sandstone lobes.
..
Strahan , A. 1898. The Geology of the Isle of Purbeck and Weymouth. Memoirs of the Geological Survey. Her Majesty's Stationery Office, London. 278 pages with a map.

Strahan, A. 1906. Guide to the Geological Model of the Isle of the Isle of Purbeck. Memoirs of the Geological Survey.
.
Strasser , A. 1986. Ooids in Purbeck limestones (lowermost Cretaceous) of the Swiss and French Jura. Sedimentology, 35, 711-727.

Strasser, A. 1988. Shallowing-upward sequences in Purbeckian peritidal carbonates (lowermost Cretaceous, Swiss and French Jura Mountains). Sedimentology, 35, 369-383.
..
Sunamura , T. 1992. Geomorphology of Rocky Coasts. John Wiley and Sons, Chichester, 302pp. By Tsuguo Sunamura, Institute of Geoscience, University of Tsukuba, Ibaraki 305, Japan. One of the Coastal Morphology and Research Publications, Series Editor - C.F. Bird. ISBN 0-471-91775-3. Includes bibliographic references and index. Contents: Introduction, Nearshore Wave Field, Water Level Factors: Tide and Storm Surges, Stengths of Landform Materials, Processes of Cliff Erosion, Underwater Bedrock Erosion, Shore Platforms, Some Characteristic Erosional Platforms, Effects of Human Activity on Rocky Coasts, References, Appendix One: Conversion Factors, Appendix Two: Worldwide Coastal Cliff Erosion Rates, Author Index, Location Index, Subject Index. [Not specifically on English south coast localities, although some are mentioned. It is very good for world-wide data and theories, and is relevant to the English south coast.]

Go back to top


..
Thomas , J. and Ensom, P. 1989. Bibliography and Index of Dorset Geology. Dorset Natural History and Archaeological Society. 102 pp. Valuable guide to Dorset geological literature including journal articles, newspaper reports and obscure publications.

Go back to top


.
Townson , W.G. 1971. Facies Analysis of the Portland Beds. Unpublished. D.Phil. thesis, Oxford University. 284 pp. By William Geoffrey Townson (Geoff. Townson). Supervised by Dr. A. Hallam.

Townson, W.G. 1974. Geology of Coombe Valley; remapped after investigation of a gas-main trench dug in October 1969. [near Chalbury and Bincombe Hill, north of Weymouth, Dorset.] Proceedings of Dorset Natural History and Archaeological Society, for 1973, published in July, 1974, vol. 95, pp. 7-8. Short paper.
[Extract: Introduction]
The Jurassic and Lower Cretaceous rocks in Dorset were laid down conformably but were folded and faulted before further deposition during the Upper Cretaceous period. In the Tertiary the strata were folded and faulted again and some of the pre-Albian high-angle faults were re-orientated to have the appearance of thrusts. Detailed information of this is given in Arkell (1947) together with an admirable map which illustrates these features on the scale of three inches to one mile (Arkell, 1947, Pl. XIX).
The geology of the area around Bincombe, Greenhill Barton and Coombe Valley is thought to differ from that depicted by Arkell. This is emphasised by Professor House (1969) in a note in these Proceedings, and implied by Miss Samuel (1969)[Samuel, E.M., 1970, Formations exposed in the trench for the natural gas main in the area southeast of Bincombe, Proceedings of Dorset Natural History and Archaeological Society, vol. 91, pp. 39-41.] in an article on the formations exposed in a trench across the area. During a study of the Portland Beds in Dorset I have examined all the outcrops and as many exposures as are available in the area shown on Arkells map. [This paper reports that the formerly termed "Black Sandstones", Parallel Bands and the West Weare "Sands" of the Isle of Purbeck and Portland are in fact dolomite, not sandstone. For more details see Townson (1975).]

Townson, W.G. 1975. Lithostratigraphy and deposition of the type Portlandian. Journal of the Geological Society, London, vol. 131, pp. 619-638, 5 figures. Key paper for the Portland strata, with good diagrams. Available online in the Lyell Collection of the Geological Society of London. By William Geoffrey Townson (now a retired petroleum geologist, Dorset geologist and geological artist).
The "Portland Beds" of Dorset (Portlandian of English usage) are described in terms of a Group comprising two Formations and seven Members. Facies and thickness variations indicate the presence of a swell separating an East from a West Basin. The swell may be due to the movement of Triassic salt [a thick sequence of Triassic salt has since been proven under the Isle of Portland]. The environmental history of the Portland Group is described in terms of three cycles consisting of a major regressive and minor transgressive phases superimposed on an overall regression. The lower cycle consists of siliciclastics and dolomite deposited in a relatively deep marine environment. The dolomite formed by in situ replacement of lime mud. The middle cycle consists of cherty fine-grained limestones deposited on the outer part of a carbonate shelf. The abundance of replaced sponge spicules adequately accounts for the amount of chert. The upper cycle consists of cherty limestones passing up into shallow water grainstones. Ooid shoals developed over the swell. These marine limestones are overlain by stromatolites and evaporites which formed on the basin margin.

Townson, W.G. 1975. Information for a Geological Field Excursion to Dorset. Field Guide, A4 size. 2nd Edition (Revised). Shell U.K. Exploration and Production Limited. 83 pp.

Townson, W.G. 1976. Discussion of Portlandian faunas. Journal of the Geological Society, London, 132, 335-336.

Go back to top


..
Tresize, G.R. 1960. Aspects of the lithology of the Wessex Upper Greensand. Proceedings of the Geologists' Association, 71, 316-339.

Go back to top


.
Underhill , J.R. and Stoneley, R. 1998. Introduction to the development, evolution and petroleum geology of the Wessex Basin. In: Underhill, J.R. (Ed.) Development, Evolution and Petroleum Geology of the Wessex Basin. Geological Society, London, Special Publications, 133, 1-18. (Key paper)

Underhill, J.R. and Patterson, S. 1998. Genesis of tectonic inversion structures: seismic evidence for the development of key structures along the Purbeck - Isle of Wight Disturbance. Journal of the Geological Society, London, vol. 155, pp. 975-992. By John R. Underhill and Susan Patterson.
The interpretation of a densely spaced and well-calibrated seismic grid sheds new light on the development and evolution of key regional and local structures in the Wessex Basin. The results help to resolve long-standing controversies concerning the tectonic significance of apparently anomalous outcrop patterns and the role of important, local ancillary structures with respect to the major monoclinal folds with which they are associated. Although the structures are entirely consistent with the effects of contractional reactivation (tectonic inversion) of normal faults, the subsurface data demonstrate the role that original extensional fault segmentation and associated relay ramps had on original depositional patterns, subsequent inversion geometries and resultant outcrop patterns. As well as illustrating regional controls on the formation of structures, the new seismic-based interpretations enable a reassessment of the Lulworth Crumple and the Ballard Down Fault. The Lulworth Crumple is interpreted as a parasitic fold complex generated by internal folding of the inverted, incompetent syn-rift fill in the immediate hanging wall to the Purbeck Fault, a reactivated major normal fault. The Ballard Down Fault's origin is interpreted to result from the formation of a local, late-stage 'out of the syncline' reverse fault which propagated southwards and upwards through a Chalk succession. As the Chalk had already been rotated to form the northward-dipping steep limb of the Purbeck Monocline at Ballard Down, the structure cuts down stratigraphically. The results stress the importance of understanding the nature of original extensional fault geometries and the competence of the sedimentary units incorporated in folds in gaining a full understanding of the genesis and evolution of structural styles in inverted basins.
[this is a key paper on south Dorset structures!]
.
Watson J. and Alvin, K.L. 1996. An English Wealden floral list, with comments on possible environmental indicators. Cretaceous Research, volume 17, number 1, February 1996 , pp. 5-26.
Abstract:
An up-to-date floral list of well-authenticated species is presented for the Lower Cretaceous, Wealden succession of England. Elements of the flora are assessed for evidence of Wealden climate and environments. Modes of preservation and plant reconstructions, as well as structural and morphological features of plant organs are used in assessment. The frequent preservation of some plants as fossil charcoal, and the occurrence of certain specialized features resembling those found today amongst fire-climax communities, suggest that fire was sometimes an important environmental factor. Growth rings in secondary wood indicate a degree of seasonality and many botanical features point strongly to the occurrence of periods of aridity.
.
Webster , T. 1816. in: Englefield, Sir H.C. 1816. A Description of the Principal Picturesque Beauties, etc., of the Isle of Wight. With additional observations on the strata of the Island, and their continuation in the adjacent parts of Dorsetshire, by T. Webster. Payne and Foss, London.

Webster, T. 1826. Observations on the Purbeck and Portland Beds. Transactions of the Geological Society, London, 2, 37-44.
..
West, I.M. 1964. Evaporite diagenesis in the Lower Purbeck Beds of Dorset . Proceedings of Yorkshire Geological Society, 34, 315-330.
[Petrographic evidence of vanished evaporites in the Caps and Broken Beds - pseudomorphs, celestite, lutecite etc. Diagenetic history established.]
Abstract: Five stages have been determined in the diagenetic history of the calcium sulphate beds of Lower Purbeck age in Dorset, particularly by reference to abundant pseudomorphs and other relict textures and structures preserved in late-formed gypsum and in secondary silica and calcite. The weight of the overburden is thought to have controlled the changes. Occurrences are described of minerals, including celestite, calciostrontianite, lutecite and quartz remaining after the removal in solution of gypsum. A description is also given of secondary limestones which occur particularly in the Caps and Broken Beds. They are shown to be almost entirely replacements of original sulphate deposits.

West, I.M. 1964. Age of the Alpine Folds of Southern England. Geological Magazine, 101, 190-191.

West, I.M. 1964. Deformation of the incompetent beds in the Purbeck Anticline. Geological Magazine, 101, p.373.
In a recent paper Williams (l961) has considered the movement of incompetent material from the limbs towards the crests and troughs of similar folds. He suggested that the shearing forces at the top of the incompetent bed differ in direction from those commonly accepted. This provides an explanation of the position of minor folds within the Purbeek Anticline. A generalized reconstruction of the major structure is shown in Text-fig. 1. This is based on the Dorset coastal sections assuming a nearly constant easterly plunge. Although complicated by unconformity, disharmonic tendencies are apparent in the anticline. This was perhaps implied by Strahan (1898, p. 218) when he suggested that Lulworth Cove lay between a region of compression below and gaping above. The difference in dip (usually at least 30 degrees) between the Chalk and the Portland Stone at most of the coastal sections may result from this type of folding. Williams' shearing forces in such a disharmonic fold are opposite to those produced by normal bed over bed sliding at the top of the incompetent beds, but in a similar direction at the base, If both forces existed during the formation of the Purbeck anticline they would tend to neutralize each other at the top of the incompetent Lower Cretaceous strata and reinforce each other at the base. This would explain the position of the Lulworth and Peveril Crumples, interpreted as drag folds by Arkell (1938), in the Purbeck Beds just above the competent Portland Stone. [continues with references and a diagram.]

West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite . Proceedings of the Yorkshire Geological Society, vol. 35, pp. 47-58.
Abstract:
A nodular structure, here termed "macrocell structure", is commonly associated with enterolithic veins in the British Purbeck gypsum and anhydrite. The veins and the macrocell structure preceded the brecciation that gave rise to the Broken Beds and were present in early secondary anhydrite. Both structures probably originated when primary gypsum was undergoing compaction before the lithification of the associated marl, and have not resulted from the hydration of anhydrite. A sequence of diagenesis for Purbeck calcium sulphate with macrocell structure is established, comparable to that previously elaborated for the calcium sulphate with net-texture. Similar features are present in other evaporite deposits.

Diagram showing postulated diagenetic history of nodular and other gypsum, Purbeck Formation, Dorset and Sussex, by Ian West, 1965




West, I.M. 1973. Vanished evaporites - significance of strontium minerals . Journal of Sedimentary Petrology, 43, 278-279. By Ian West. [A short note, reproduced in full beneath]

In a recent paper, Folk and Pittman (1971) have clearly indicated the importance of the lutecite and quartzine varieties of chalcedony as evidence for the former presence of evaporites. Although lutecite (fig. 1) has been successfully employed by the present writer for the detection of former gypsum deposits removed by dissolution (West, 1964; West, Brandon and Smith, 1968), confirmatory evidence is usually necessary. Fortunately those processes which cause the removal of evaporites in solution frequently also result in their partial replacement by other minerals.
Groundwater with bicarbonate ions may partly convert calcium sulphate deposits to calcium carbonate before dissolution of any remaining gypsum. Examples of such calcitized evaporites have been described by West (1964), Shearman and Fuller (1969) and other authors. In a dolomitic succession the calcitic nature of such replacements may be conspicuous. Pseudomorphs, relics of anhydrite in euhedral quartz crystals, and traces of net-texture (West, 1964) or nodular structure (West, 1965) may be present in any replacements or residues of dissolved evaporites. A positive indication of the former presence of calcium sulphate is the occurrence of celestite. This mineral is rarely found in sedimentary deposits other than evaporites, replaced evaporites or insoluble residues of evaporites. The related mineral barite is not so restricted. Associations of celestite with present or former evaporites have been described by Lacroix (1897), Zaritsky (1961), West (1964), West, Brandon and Smith (1968) and many other authors. Celestite is, in most cases, formed by the replacement of gypsum or anhydrite; it is much less soluble than those minerals. It is usually formed by selective removal of strontium ions from groundwater by reaction with deposits of calcium sulphate.

Lutucite pseudomorph after a lenticular crystal of gypsum, Lower Purbeck, Durlston Bay, Dorset

FIG. 1. Lutecite pseudomorph after a lenticular crystal of gypsum. Adjacent moulds have been left by the dissolution of gypsum crystals. Lower Purbeck Beds, Durlston Bay, Dorset. Partly crossed polars. X 43.

Water containing a large proportion of calcium ions and a small proportion of strontium ions most commonly exists where limestone deposits occur in proximity. Celestite beds of appreciable thickness may be thus formed, particularly at the upper or lower boundaries of gypsum or anhydrite deposits. Such diagenetic formation of celestite is most favoured where there is an appreciable flow of groundwater. Continuing diagenesis in a bicarbonate- rich environment may convert celesrite to calciostrontianite (Salter and West, 1965).

Small-scale occurrences of celestite may be produced by a similar mechanism where gypsum veins have penetrated into limestone. Examples occur in the marine Portland Stone of Dorset where eelestite casts of fossils are replacements of gypsum or anhydrite which has penetrated down from the overlying Purbeck Beds.

Fig. 2. Lutecite spherulites in celestite. Basal Purbeck gypsum deposit. Mountfield Mine, Sussex. Partly crossed polars. X 36.

Similarly in Rhaetic limestones [Penarth Group, Trias] of southern England gypsum veins originating from underlying Triassic strata have been converted to celestite. Thus, there are many criteria for indicating the former presence of evaporites and it is wise to employ at least two. The occurrence of strontium minerals together with length-slow chalcedony (fig. 2) [and/or lutecite] provides reliable evidence of the former presence of evaporites.

[REFERENCES (for this paper only; continue down for main reference list )
Folk, R. L. and Pittman, J. S., 1971. Length-slow chalcedony: a new testament for vanished evaporites: Journal of Sedimentary Petrology, v. 41, pp. 1045-1058.
Lacroix, A. 1897, Le gypse de Paris et les mineraux qui l'accompagnent: Nouvelle. Arch. Mus. Hist. Nat., Paris, vol. 9, pp. 201-296.
Salter, D. L. and West, I. M., 1965, Calciostrontianite in the basal Purbeck Beds of Durlston Head, Dorset: Mineralogical Magazine, vol. 35, p. 146-150.
Shearman, D.J. and Fuller, J.G. 1969, Anhydrite diagenesis, calcitization and organic laminites, Winnipegosis Formation, Middle Devonian, Saskatchewan: Bulletin of Canadian Petroleum Geology, vol. 17, p. 496-525.
West, I. M., 1964, Evaporite diagenesis in the Lower Purbeck Beds of Dorset: Proceedings of Yorkshire Geological Society, vol. 34, pp. 315-330.
West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite. Proceedings of the Yorkshire Geological Society, vol. 35, pp. 47-58.
West, I.M., Brandon, A. and Smith, A. 1968 A tidal flat evaporitic facies in the Vis6an of Ireland. Journal of Sedimentary Petrology, vol. 38, pp. 1079-1093.
Zaritsky, P. V., 1961, Celestite from the Lower Permian deposits of the Donbas: Doklady, vol. 133, pp. 801-804.]
[END OF THIS PAPER]



West , I.M. 1975. Evaporites and associated sediments of the basal Purbeck Formation (Upper Jurassic) of Dorset. Proceedings of the Geologists' Association, London, 86, 205-225.
Abstract: Four facies of limestones, each with particular contents of calcitised evaporites and of skeletal debris were recognised. They are compared with sediments of modern evaporite-depositing environments. The lowermost limestones, stromatolitic and pelletoid with foraminifera, probably originated in intertidal to shallow subtidal, moderately hypersaline, water. Overlying pelletoid limestones with algal-mats and some gypsum are products of high-intertidal flats. The main evaporite beds were originally gypsum, probably formed in supratidal to intertidal, very hypersaline, palaeoenvironments. The gypsum was converted to anhydrite and later brecciated in part, forming the Broken Beds. Extensive calcitisation produced porous unfossiliferous limestones. Ostracodal limestones above probably originated in shallow, only moderately hypersaline water. All the basal Purbeck strata were formed in and around a large shallow gulf with extensive tidal flats and with water of varying but predominantly high salinities. At times of uplift, thin soils developed on the former margins of the gulf. Forests were able to exist there because, although the area was within the semi-arid zone, it was probably very near to the boundary of the warm-temperate zone. End of Abstract. [Additional notes on topics discussed: Palaeosalinity origins of the basal Purbeck facies and lateral correlation. Mostly hypersaline to varying extents, including the stromatolite horizons. Fossil trees 'pickled' in a salt lake. Details of the basal Purbeck strata at all the main localities, studied petrographically. Depositional environments of the dirt beds and marls. Palaeoenvironmental significance of sedimentary cyles. Thickness variations of the facies. Relationship of the Broken Beds to the evaporitic facies. Local uplift. Penecontemporaneous fault movement. The Mupe Bay oil sand.]





..
Wethered , E. 1890. On the occurrence of fossil forms of the genus Chara in the Middle Purbeck Strata of Lulworth, Dorset. Proceedings of the Cotteswold Naturalists Field Club, 10, 101-103.
..
Wimbledon, W.A., Allen, P. and Fleet, A.J. 1996. Penecontemporaneous oil-seep in the Wealden (early Cretaceous) at Mupe Bay, Dorset, U.K. Sedimentary Geology, 102, 213-220. Abstract: Investigation of an oil-globule enveloped in laminated silty clay shows that oil, derived from the Lias, impregnated early Wealden alluvial sediments penecontemporaneously and later. Some of the earlier oil reached the surface of the floodplain and seeped from the eroding bank of an ephemeral river. Lag-sediment in the channel, comprising debris from the oily alluvium, was invaded by later oil (or oils). The palaeoseep was geologically short-lived. Relevant geochemical and petrological data and the geological context are presented. Process-models based on fault and/or water-table controls on oil migration are briefly proposed.
..
Woodward , H.B.1895. The Jurassic Rocks of Britain. Vol 5. The Middle and Upper Oolitic Rocks of England (Yorkshire excepted). Memoirs of the Geological Survey of the United Kingdom. 499pp.

[end of the MAIN LIST - the undivided section of publications]



Go back to top

2. Conservation - Geological

[end of Conservation Section]

Go back to top

4. Geomorphology
.
Belov , A.P., Davies, P. and Williams, A.T. 1999. Mathematical modeling of basal coastal cliff erosion in uniform strata: A theoretical approach. Journal of Geology,107, 99-109. Abstract: This article utilizes the general assumption that cliff erosion is dependent on the strength of wave assailing forces and the resistance of the cliff material. It considers the possibility of understanding and describing coastal cliff erosion processes, particularly basal erosion, through a mathematical analysis of one of the clearest manifestations of its action, i.e., the development of the basal cliff notch through mechanical wave action. It analyzes profile change through time, assuming a cliff composed of uniform strata. Deterioration of the cliff is expressed by means of the erosion function, which in this study is related to the cliff erosion rate. An equation, termed the Belov, Davies, Williams (BDW) equation, has been formulated for a moving surface, and this is proposed as a mathematical model of cliff profile change. Explicit solutions of the BDW equation are found for both steady state and time-dependent erosion rates. In both cases, it is assumed that wave erosion intensity decreases exponentially with height. Solutions obtained showed that cliff retreat, related to basal notching, depends upon the erosion intensity and magnitude of the geophysical parameters. The model predicted the occurrence of cliff basal notching, the depth of which is comparable to field observations and can be applied to other locations. It is believed the approach and model has the potential to be developed further for other structural contexts such as locations with a variable lithology. [Not on the Lulworth area but it presents mathematical models useful for comparison with cliff profiles.]
.
Goudie , A. and Brunsden, D. 1997. Classic Landforms of the East Dorset Coast. Published by the Geographical Association in conjunction with the British Geomorphological Research Group. Sheffield. 48 pp. Series Editors - Rodney Castleden and Christopher Green. Low cost paperback , pocket size booklet. Concise with excellent colour illustrations including good aerial photographs. Sections comprise: Introduction, the Portland Cliff, the Portland Raised Beach, the south Dorset coast, the Lulworth Coast, the east Purbeck coast, Studland Bay and the South Haven Peninsula, Poole Harbour, Glossary, Bibliography. (see also companion volume on West Dorset). In summary this guide is concise, clear, colourful and cheap. It contains some minor errors in the diagrams but it is very good. There is basic information for the beginner and, for experienced geologist and geomorphologist, some good new discussion and data, particularly with regard to Portland and Lulworth. It is well-worth purchasing and using with Michael House's guide to the geology of the Dorset coast.
.
Higgins , C.G. 1980. Nips, notches, and the solution of coastal limestone: an overview of the problem with examples from Greece. Estuarine and Coastal Marine Science, 10, 15-30. [Not specifically on the Lulworth area, but relevant to the notches of the coast near Durdle Door.]
.
Steers , J.A. 1946. The Coastline of England and Wales. Cambridge University Press, and 2nd Edition 1964.

Steers, J.A. 1960. The Coast of England and Wales in Pictures. Cambridge University Press. 146.

Steers, J.A. 1981. Coastal Features of England and Wales. The Meander Press, Cambridge.
.
Sunamura , T. 1992. Geomorphology of Rocky Coasts. John Wiley and Sons, Chichester, 302pp. By Tsuguo Sunamura, Institute of Geoscience, University of Tsukuba, Ibaraki 305, Japan. One of the Coastal Morphology and Research Publications, Series Editor - C.F. Bird. ISBN 0-471-91775-3. Includes bibliographic references and index. Contents: Introduction, Nearshore Wave Field, Water Level Factors: Tide and Storm Surges, Stengths of Landform Materials, Processes of Cliff Erosion, Underwater Bedrock Erosion, Shore Platforms, Some Characteristic Erosional Platforms, Effects of Human Activity on Rocky Coasts, References, Appendix One: Conversion Factors, Appendix Two: Worldwide Coastal Cliff Erosion Rates, Author Index, Location Index, Subject Index. [Not specifically on English south coast localities, although some are mentioned. It is very good for world-wide data and theories, and is relevant to the English south coast.]
.
Wentworth , C. K. 1939. Marine bench-forming processes: 2, solution benching. Journal of Geomorphology, 2, 3-25. [Not on the Lulworth area, but relevant to the notch at Bats Head.]

[end of Geomorphology Section]

Go back to top

5 Maps - Geological and Topographic

(Flat or folded copies geological maps can be ordered from the Sales Desk, British Geological Survey , Nottingham, NG12 5GG (Tel. 0115-936 3241 Fax 0115-936 3488) or obtained by visiting the BGS London Information Office at the Natural History Museum (Tel. 020-7589-4090).

British Geological Survey 1:50,000 geological map - Swanage, Sheet 343 and 342. This is one of three main geological maps published on the area. It covers the Isle of Purbeck with Lulworth Cove in the western part. A new edition has been published in 2000.
.
British Geological Survey. 1974. 1:50,000 geological map - Weymouth, Sheet 342. [This covers Weymouth and Portland with Lulworth Cove in central part (a large part of this map is sea, the geology of which is not shown). It extends from west of Weymouth to east of Kimmeridge and northward to Winfrith Newburgh. This map, based on a survey of 1896, is more reliable and easier to read than the new 2000 West Fleet and Weymouth Sheet (see House (2001) and details given here), and is recommended for use as the standard geological map for the area (perhaps with the new map as a supplement).]

British Geological Survey. 2000. Geological Map: West Fleet and Weymouth. 1:50,000 Series, England and Wales Sheet 341 and part of sheet 342. Solid and Drift, with seafloor geology, cross-sections and other data. New map. [This commences just to the west of Durdle Door, Lulworth and includes Bats Head. It extends from here westward to Abbotsbury, including all the Fleet Lagoon and the Isle of Portland. It provides a cover of most of the Weymouth Anticline. The continuation southward onto seafloor geology is something that the previous Weymouth and Fleet maps do not have. There are large, north-south cross-sections based on boreholes and seismic data. These show deep faulting and such features of interest as the thickness and distribution of evaporites in the Permo-Trias. It has good structural contour maps for the top Penarth Group and the top Corallian and other information, such as sea-floor sediment data for the offshore area around Weymouth and Portland.

There are clearly different views on this map. It has been favourable reviewed by David Nowell (2001) in the Circular of the Geologists' Association No. 949 for December, 2001. Referring to this and the new sheet for Swanage (342 east and part of 343) and for Dorchester (328). Amongst other favourable points, he commented that: " These maps have completely revised stratigraphic units that more fully reflect the distribution of the different rock types and recognisable sequences within the sediments of southern Dorset that, across country, can be mapped in greater detail than was previously possible. The clearest changes are to the traditional lower, middle and upper divisions of the Chalk, which have been replaced by up to eight formations, while the Purbeck is divided into five members of the Durlston and Lulworth Formations. Another necessary change, even if it is slightly garish, is the effective use of red and grey tones to show the complex sand and clay variations within the Eocene sequence, which was deposited after the uplift and erosion of the Chalk.... These splendid maps can be thoroughly recommended to anyone who is interested in the picturesque and fascinating geology of southern Dorset. Flat or folded copies cost £9.95p. each and can be ordered from the Sales Desk, British Geological Survey, Nottingham, NG12 5GG (Tel. 0115-936 3241 Fax 0115-936 3488) or obtained by visiting the BGS London Information Office at the Natural History Museum (Tel. 020-7589-4090)."

Although the Weymouth map certainly provide more details, in terms of members there are also, unfortunately, some problems (which one hopes will be corrected in later editions). Some of the defects have been discussed by Professor Michael House (2001) who has mapped the Weymouth area in detail. Most of these are not considered here, and reference should be made to his article. Most easily seen, and most affecting the coastal geology, are anomalies in outcrop and symbols in the offshore around Bats Head to White Nothe. The offshore rocks of Portland Stone at Bats Head, the Cow and the Calf have been placed not in a Portland outcrop but in the Chalk Group. As Professor House (2001) House points out their Portland Stone composition has been known since 1818. Indeed, in the past the Geological Survey has always described them correctly. Strahan (1898), for example, stated "Its [Portland Stone] further course under the sea is marked by ..... by the Bull, and the Blind Cow, the Cow and the Calf Rocks, all portions of a submerged escarpment of vertical Portland Stone running parallel to the vertical Chalk of the adjacent coast." See also the data in Donovan and Stride (1961). The 1974 edition of the Weymouth map actually comments on "vertical, outlying rocks of Portland Stone". Furthermore there seem to be some other strange aspects of mapping in this area. The well-known foresyncline of Chalk here is shown with the symbols of an anticline and the Chalk outcrop is too wide. On the south side of the fold the Chalk is shown in apparently unconformable contact with the Portland and Purbeck strata. In fact, the "Late Kimmerian" unconformity here is the base of the Gault, not the Chalk. The Chalk could only be in contact with Purbeck by faulting, but a fault is not shown.

The earlier British Geological Survey Map Offshore Map, the 1:250,000 sheet - Portland 50N04W clearly shows Gault and Upper Greensand between the Chalk and the Purbeck. The 1974 edition of the 1:50,000 Weymouth Sheet, 342, is clear, trustworthy and well-labelled and shows correct features in this Bats-Head to Whitenothe area. The new sheet of 2000 certainly contains much useful supplementary information but would be much better if revised, at least as far as correcting significant errors.

Another aspect, less important, is the use of the so-called "Lulworth Formation"and "Durlston Formation". This is a little strange, because it seems to break the rules of stratigraphic nomenclature. These are not true lithostratigraphic units (formations) but represent a renaming of unsatisfactory divisions based on mixed chronostratigraphy and lithostratigraphy ("Lulworth Beds" and "Durlston Beds"). There were set up for a special purpose by Casey (1963 p. 14), contrary to modern methods, when the Jurassic-Cretaceous boundary was placed between them, on the basis of circumstantial correlation with the Russian boundary. The Jurassic-Cretaceous boundary, which is in any case now placed lower, is not relevant to lithostratigraphy. It is clearly preferable in the future, however, to follow normal stratigraphical rules and not to use these anomalous "formation" names.

British Geological Survey 1:250,000 Series, Portland Map, Sheet 50 degrees N. -0.4 degrees W. This includes Lulworth Cove but is on a smaller scale and more complex. It does, however, include an enlargement of the area south of the cove which is based on the work of Donovan and Stride (1961).

British Geological Survey - Institute of Geological Sciences and Wessex Water Authority. 1979. Hydrogeological Map of the Chalk and Associated Minor Aquifers of Wessex. Including parts of hydrographic areas 43, 44 and 53. Scale 1:100,000. Lulworth Cove (very small) is in the central southern part of the map. Useful for appropriate specialists.
.
Ordnance Survey, 1:25,000 maps, Outdoor Leisure Series, 15, Purbeck and South Dorset. A specially designed map of this popular recreational area. This is the recommended topographic map for geologists using the area. It includes Swanage, St Albans Head, Worbarrow Bay, Lulworth Cove, White Nothe, Weymouth, Portland and the Chesil Beach to West Bay and Bridport. Larger scale maps - 1:10,000, and 1:2,500 can be obtained from map suppliers for specific area, such as Lulworth Cove or Durdle Door. These would be needed for student project work or research. References for the larger scale maps can be obtained from the National Grid which is shown on the 1:25,000 map. The 1:2500, large scale, Durdle Door map is SY 8080, SY being the index letters for the area and 80 being the easting and 80 also being the appropriate northing. The reference is given from the southwestern corner and remember - "eastings before northings"! St Oswald's Bay is SY 8180, Lulworth Cove is SY 8279 (the northern part is in SY 8280) and the Fossil Forest is in SY 8379. Aerial photographs are also available from the Ordnance Survey.

[end of Maps Section]

Go back to top

6. Portland Group


.
Arkell, W.J. 1935. The Portland Beds of the Dorset Mainland. Proceedings of the Geologists' Association, 46, 301-347.

Arkell, W.J. 1947. The Geology of the Country around Weymouth, Swanage, Corfe and Lulworth. Memoir of the Geological Survey, 386 pp. (Discussion of Portland strata including the sequence at Dungy Head - see pages 109 and 110. A section at Dungy Head is given)
.
Blake , J.F. 1880. On the Portland rocks of England. Quarterly Journal of the Geological Society of London, 36, 189-236.
.
Coe , A, L. 1996. Unconformities within the Portlandian Stage of the Wessex Basin and their sequence stratigraphical significance. In: Hesselbo, S.P. and Parkinson, D.N. 1996. Sequence Stratigraphy in British Geology. Geological Society Special Publication No. 103, 384 pp, ISBN 1-897799-49-7. By Dr. Angela Coe.
.
Cope , J.C.W., Duff, K.L., Parsons, C.F., Torrens, H.S., Wimbledon, W.A. and Wright, J.K. (1980). A correlation of Jurassic rocks in the British Isles. Part two: Middle and Upper Jurassic. Geological Society of London, Special Report, 15: 1- 109.
.
Cox , L.R. 1929. Synopsis of the Lamellibranchia and Gastropoda of the Portland Beds of England. Proceedings of Dorset Natural History and Antiquarian Field Club, 50, 131-202.
.
Latter , M.P. 1926. The petrography of the Portland Sand of Dorset. Proceedings of the Geologists' Association, London, 37, 73-91
.
Quest , M. 1985. Petrographic and Geochemical studies of the Portland and Purbeck Beds of Dorset. Unpublished Ph.D. Thesis, Geol. Dept., University of Birmingham, England, 347pp. [stable isotope and trace element studies]
.
Townson, W.G. 1971. Facies Analysis of the Portland Beds. Unpubl. D.Phil. Thesis, Oxford Univ., 284pp.

Townson, W.G. 1975 Lithostratigraphy and deposition of the type Portlandian. Journal of the Geological Society, London, 131, 619-638.

Townson, W.G. 1976. Discussion of Portlandian faunas. Journal of the Geological Society, London, 132, 335-336.
.
Wilson , R.C.L. 1967. Diagenetic carbonate fabric variations in Jurassic limestones of southern England. Proceedings of the Geologists' Association, London, 78, 535-554.
.
Wimbledon , W.A. and Cope, J.C.W. 1978. The ammonite faunas of the English Portland Beds and the zones of the Portlandian Stage. Journal of the Geological Society, London, 135, 183-190.
.
Woodward , H.B. 1895. The Jurassic Rocks of Britain. Vol 5. The Middle and Upper Oolitic Rocks of England (Yorkshire excepted). Memoirs of the Geological Survey of the United Kingdom. 499pp.

[end of Portland Section]

Go back to top

7. Purbeck Formation

(See also more extensive Purbeck literature lists in relation to the type section at Durlston Bay and a general Purbeck Bibliography )

Bibliography of the Purbeck Formation

Purbeck Type Section at Durlston Bay Additional Purbeck information is given here.

Purbeck Type Section at Durlston Bay - Bibliography Additional Purbeck references, specifically in relation to Durlston Bay, are given here.

Fossil Forest Field Trip. Additional Purbeck information and references are given here.
.
Brown , P.R. 1961. Petrology of the Lower and Middle Purbeck Beds of Dorset. Unpublished Ph.D. thesis, Liverpool University, 205 pp.

Brown, P.R. 1963. Algal limestones and associated sediments in the basal Purbeck of Dorset. Geological Magazine, 100, 565-573.

Brown, P.R. 1964. Petrography and origin of some upper Jurassic beds from Dorset, England. Journal of Sedimentary Petrology, 34, 254-269.
.
Clements , R.G. 1969. Annotated cumulative section of the Purbeck beds between Peveril Point and the Zig-zag path, Durlston Bay. In: H.S. Torrens (Ed.) International Field Symposium on the British Jurassic, Excursion No. 1, Guide for Dorset and South Somerset. University of Keele, pp. 44-71. 71p. total. This is not on Lulworth Cove but it provides a thorough description of the type section which can be used for comparision.

Clements , R.G. 1993. Type-section of the Purbeck Limestone Group, Durlston Bay, Swanage, Dorset. Proceedings of the Dorset Natural History Arch. Society , 114 for 1992, 181-206. Classic section log. This is an improved version of the 1969 one above with much valuable detail. Again, it is not on the Lulworth area but it is needed to understand the Purbeck succession. See also the Ensom log of Worbarrow Tout.
.
El-Shahat , A. l977. Petrography and Geochemistry of a Limestone Shale Sequence with Early and Late Lithification: the Middle Purbeck of Dorset,England. Unpublished Ph.D.Thesis , University of Southampton. 295 pp. By Dr. Adam El-Shahat.

El-Shahat , A. and West, I.M. 1983. Early and late lithification of some aragonitic bivalve beds in the Purbeck Formation (Upper Jurassic - Lower Cretaceous) of southern England. Sedimentary Geology, 35, l5-4l.
..
Francis , J. E. 1983. The Fossil Forests of the Basal Purbeck Formation (Upper Jurassic) of Dorset, Southern England: palaeobotanical and palaeoenvironmental investigations . Unpublished Ph.D. Thesis, University of Southampton. 295 pp. By Dr. Jane Elizabeth Francis, now at Leeds University. Abstract: During the Upper Jurassic, coniferous forests grew adjacent to the Purbeck evaporitic basin in Dorset: The palaeobotany of the forests is described for the first time and the Purbeck forest environment reconstructed. The basal Purbeck Formation of Dorset was deposited during minor transgressive and regressive phases on the borders of a shallow hypersaline basin. The sediments include evaporites, hypersaline intertidal algal stromatolitic sediments and lagoonal pelletoid silts interbedded with supratidal algal mat sediments. The unusual features are brecciated calcrete and calcareous marls representing former forest soils. The trees which grew in the rendzina-like palaeosols of the Lower and Great Dirt Beds are now preserved in situ as silicified tree stumps and branches. They were drowned by rising hypersaline water and preserved within mounds of algal stromatolitic sediment. The wood was rapidly silicified by length-slow chalcedony (quartzine), a type of silica commonly associated with evaporitic environments. The fossil forests were dominated by one type of conifer belonging to the extinct family Cheirolepidiaceae. The wood of this is designated Protocupressinoxylon sp. A nov., the small scale-like leaves are Cupressinocladus valdensis (Seward) Seward and the small male cones Classostrobus sp. Alvin, Spicer and Watson. The tree is a source of Classopollis Pflug pollen so widespread in the Jurassic. A reconstruction of this Purbeck tree, based on evidence from fossil remains, is presented. The trees were monopodial with low branches and shallow spreading roots and formed fairly dense, closed forests. A few other conifer species were also present but much less abundant and cycadophytes (Bennettitales) are also represented by their silicified stems. The miospore assemblage from the palaeosols is dominated by Classopollis pollen (70% of samples), but also represents a rather poor flora of filicalean and lycopsid plants. Comparison with modern tree-ring data from semi-arid regions suggests a Mediterranean-type of climate for the Purbeck with warm, wet winters and hot, dry summers. The markedly seasonal nature of the climate is supported by sedimentary and faunal evidence such as ephemeral lake sediments containing both a freshwater fauna and flora plus evaporites. Modern analogues to the Purbeck environment have been found in the Mediterranean areas of the southern parts of Australia. The environment of the Callitris forests of Rottnest Island, Western Australia, appears remarkably similar to that of the~Purbeck forests. This type of seasonal, semi-arid climate during the Upper Jurassic accounts for the paradoxical association of evaporites with well developed forest vegetation. It contrasts with the widely held view, that the Jurassic climate was warm and equable. The reconstruction of the Purbeck trees and forest environment may serve as a model for other Upper Jurassic and Lower Cretaceous vegetation.

Francis, J.E. 1983b. The dominant conifer of the Jurassic Purbeck Formation, England. Palaeontology, 26, 277-294. Abstract: Fossil trees are preserved in situ in fossil soils in the Lower Purbeck (Upper Jurassic) strata of Dorset. Silicified tree stumps, still rooted in the soils, stand erect and protrude into the overlying limestones. Numerous trunks and branches lie on the soils, which also contain conifer shoots. The forests were dominated by one kind of conifer with wood, named here as Protocupressinoxylon purbeckensis sp. nov., foliage belonging to the species Cupressinocladus valdensis (Seward) Seward and with male cones yielding Classopollis pollen. A reconstruction of the anatomy and habit of the tree is given. The Lower Purbeck palaeoclimate is discussed using the evidence of tree growth rings and the character of the associated sediments.

Francis, J.E. 1984. The seasonal environment of the Purbeck (Upper Jurassic) fossil forests. Palaeogeography, Palaeoclimatology, Palaeoecology, 48, 285-307. Abstract: In the basal Purbeck Formation of Dorset a paradoxical association of evaporites and fossil forest vegetation is found, representing well-developed gymnosperm forests which grew on the borders of the shallow, hypersaline Purbeck lagoon which covered southern England during the late Jurassic. The dominant tree was a cheirolepidiaceous conifer which appears from its morphology to have been adapted to growing in a semi-arid environment. The narrow and variable growth rings of the trees indicate that conditions were marginal for tree growth and highly irregular from year to year. Comparison with modern tree-ring data suggests that the Purbeck climate was of Mediterranean type, with warm wet winters when the trees were able to grow but with hot, arid summers suitable for the formation of evaporites. The seasonal nature of the climate is also reflected in adjacent sediments, including a clay containing both fresh-water fossils and evaporites, calcrete crusts in the palaeosols, the nature of the silicification and the presence of seasonal crustaceans in finely laminated shales. Analogous modern environments for both the forests and the seasonal lagoonal sediments can be found in the Mediterranean-type climatic regions of South Australia. This evidence shows that within the "equable" Jurassic climate marked seasonal variations affected the whole environment. The seasonal nature of this climate supports recent palaeoclimatic models which propose that such a climate prevailed along mid-latitude continental margins during the Mesozoic.

Francis, J. E. 1986. The Calcareous Paleosols of the Basal Purbeck Formation (Upper Jurassic) Southern England. p. 112-138 in: Wright, V.P. (Ed.) Paleosols: Their Recognition and Interpretation. Blackwell, Oxford. ISBN 0-632-01336-2. By Dr. Jane Francis of Leeds University. Summary: Rendzina paleosols are preserved within a sequence of marginal continental deposits of algal stromatolitic and pelletoid limestones, constituting the basal part of the Lower Purbeck Formation in Dorset. The Great Dirt Bed is the most well-developed paleosol exhibiting a characteristically simple A/C rendzina profile, consisting of a dark organic-rich horizon overlying limestone bedrock. The main component of the matrix of the A-horizon is decomposed plant debris. There is little evidence of the activity of soil organisms and a notable absence of a pelletoid moder fabric, the faecal pellet textures typical of modern rendzinas. The upper O-horizon of undecomposed plant litter is also lost. This soil supported a conifer forest of slow-growing shallow rooted trees, now preserved in situ as silicified tree trunks and carbonized roots. Pebbles derived from the underlying limestone are incorporated in the soil matrix. Some consist of blackened sediment derived from a desiccated and fractured organic-rich deposit previously formed on the margins of the adjacent lagoon. The semi-arid, seasonal Purbeck climate promoted the formation of laminated and mottled deposits of secondary carbonate or calcrete, present as micritized bedrock, laminar rinds and cement around pebbles. This was itself brecciated by the soil processes and probably also by the mechanical action of the tree roots, then to become incorporated into the solum as pebbles. The Lower and Basal Dirt Beds are immature forms of rendzinas, with similar simple profiles of organic-rich layers with high carbonate content, overlying marl and devoid of large pebbles. The Lower Dirt Bed also supported a forest of conifers and cycadophytes. Each paleosol is capped by algal limestone, which originated as algal-bound sediment formed when rising saline lagoon water successively inundated the forests. This covered the tree stumps and the top of each soil with a protective layer of sediment, ensuring the rather exceptional preservation of these paleosols with in situ tree stumps. [Key paper on the Basal Purbeck Dirt Beds of Lulworth and Portland.]
.
House , M. R. 1993. Geology of the Dorset Coast. Geologists' Association Guide, 162pp.

Marshall , J. D. 1982. Isotopic composition of displacive fibrous calcite veins: reversal in pore-water composition trends during burial diagenesis. Journal of Sedimentary Petrology, 52, 0615-0630.
.
Phillips W.J. 1964. The structures in the Jurassic and Cretaceous rocks on the Dorset coast between White Nothe and Mupe Bay. Proceedings of the Geologists' Association, London, 75, (4), 373-405. By W.J. Phillips, Department of Geology, University College of Wales, Aberystwyth. Abstract: The structures associated with the steep, northward inclined Portland and Purbeck Beds, and the nearly vertical or overturned Wealden Beds and Chalk, exposed on the Dorset coast between White Nothe and Mupe Bay, form the subject of an important paper by W. J. Arkell (1938). Arkell thought that the structures occurred on the steep north limb of a major monocline which was formed by lateral pressures from the south. In the present paper the minor structures in the Purbeck Beds are described in detail and it is shown that they can be related to the development of a fold formed by the increasing northward dip of the underlying massive Portland Beds. The direction of overturning of the minor folds indicates movement of the beds down the dip slope and not upward drag as postulated by Arkell. The formation of the sets of shear planes and faults recognised by Arkell in the Chalk is considered, and it is suggested that they can be divided into two genetic groups. The first group of structures formed during the closing of the syncline, while the second group brought about its modification by thrust displacements on southward inclined thrust planes and late faults. Arkell's conclusions concerning the causes of the reduction in the thickness of the incompetent Wealden Beds are summarised briefly, but by the construction of cross-sections of the main structure, it is demonstrated that the missing portions of the Purbeck and Wealden successions could have been displaced only by thrust movements on southward inclined major faults. A stage-by-stage synthesis of the development of the structures is presented and it is suggested that they were formed as the result of the accommodation of the blanket of largely unconsolidated sedimentary beds above a major thrust fault in the basement. At first a broad flexure developed and this became most pronounced in the highest division, the Chalk, because of the buckling and northward sliding of these beds off the rising land to the south. As the magnitude of the fault increased, successively higher beds fractured and eventually the fault extended to the surface and brought about the displacement and modification of the structures formed during the earlier phase of folding.
.
Pugh , M.E. 1968. Algae from the Lower Purbeck limestones of Dorset. Proceedings of the Geologists Association, 79, 513-523. By Mary Pugh.
.
Thomas , J. and Ensom, P. 1989. Bibliography and Index of Dorset Geology. Dorset Natural History and Archaeological Society, Dorchester, Dorset, 102p. see p.96 for index. [Many useful Purbeck references.]
.
Quest , M. 1985. Petrographic and Geochemical studies of the Portland and Purbeck Beds of Dorset. Unpublished Ph.D. Thesis, Geology Department, University of Birmingham, England, 347pp.
.
B>West , I.M. 1960. On the occurrence of celestine on the Caps and Broken Beds at Durlston Head, Dorset. Proceedings of the Geologists' Association, 71, 391-401. By Ian West. Abstract: An occurrence of celestine in the Lower Purbeck Beds at Durlston Head is described and shown to be of syngenetic origin. Deposition probably took place near the margin of a basin of evaporite deposits into which strontium solutions were introduced. At a later date the celestine has been involved both in the brecciation that formed the Broken Beds and in complex local faulting. [This record of strontium minerals was the first definate evidence of former evaporites in the Broken Beds. It supported the hypothesis of Hollingworth (1938) that gypsum or anhydrite were once present at this horizon. The precise origin of the celestite, however, was not well-understood at that time, and it was later shown to be a replacement of evaporites (connected with groundwater flow up the fault-plane) and not syngenetic. See West (1973; 1975). The cliff section (fig. 2) is of a downbulge into former evaporites, and is a relatively complex part of the Durlston Bay cliffs that is not easily interpreted at first sight. Two celestite horizons are present, but the palaeosols of the Lulworth area are not properly developed here because this locality is in the "basinal" facies of the Purbecks. Since this paper was written celestite has been found in the Purbecks in the Soft Cockle Member of Durlston Bay and the Isle of Portland, in the Caps and Broken Beds at Worbarrow Tout and at Stair Hole. Calciostrontianite also occurs at Durlston Head (Salter and West, 1965).]

West , I.M. 1964. Deformation of the incompetent beds in the Purbeck Anticline. Geological Magazine, 101, p.373. [Lulworth Crumples in the Upper Purbecks]

West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite. Proceedings of the Yorkshire Geological Society, 35, 47- 58.

West, I.M. 1964. Evaporite diagenesis in the Lower Purbeck Beds of Dorset. Proceedings of Yorkshire Geological Society, 34, 315-330. [Petrographic evidence of vanished evaporites in the Caps and Broken Beds - pseudomorphs, celestite, lutecite etc. Diagenetic history established.] Abstract: Five stages have been determined in the diagenetic history of the calcium sulphate beds of Lower Purbeck age in Dorset, particularly by reference to abundant pseudomorphs and other relict textures and structures preserved in late-formed gypsum and in secondary silica and calcite. The weight of the overburden is thought to have controlled the changes. Occurrences are described of minerals, including celestite, calciostrontianite, lutecite and quartz remaining after the removal in solution of gypsum. A description is also given of secondary limestones which occur particularly in the Caps and Broken Beds. They are shown to be almost entirely replacements of original sulphate deposits.

West, I.M. 1975. Evaporites and associated sediments of the basal Purbeck Formation (Upper Jurassic) of Dorset. Proceedings of the Geologists' Association, London, 86, 205-225. Abstract: Four facies of limestones, each with particular contents of calcitised evaporites and of skeletal debris were recognised. They are compared with sediments of modern evaporite-depositing environments. The lowermost limestones, stromatolitic and pelletoid with foraminifera, probably originated in intertidal to shallow subtidal, moderately hypersaline, water. Overlying pelletoid limestones with algal-mats and some gypsum are products of high-intertidal flats. The main evaporite beds were originally gypsum, probably formed in supratidal to intertidal, very hypersaline, palaeoenvironments. The gypsum was converted to anhydrite and later brecciated in part, forming the Broken Beds. Extensive calcitisation produced porous unfossiliferous limestones. Ostracodal limestones above probably originated in shallow, only moderately hypersaline water. All the basal Purbeck strata were formed in and around a large shallow gulf with extensive tidal flats and with water of varying but predominantly high salinities. At times of uplift, thin soils developed on the former margins of the gulf. Forests were able to exist there because, although the area was within the semi-arid zone, it was probably very near to the boundary of the warm-temperate zone. End of Abstract. [Additional notes on topics discussed: Palaeosalinity origins of the basal Purbeck facies and lateral correlation. Mostly hypersaline to varying extents, including the stromatolite horizons. Fossil trees 'pickled' in a salt lake. Details of the basal Purbeck strata at all the main localities, studied petrographically. Depositional environments of the dirt beds and marls. Palaeoenvironmental significance of sedimentary cyles. Thickness variations of the facies. Relationship of the Broken Beds to the evaporitic facies. Local uplift. Penecontemporaneous fault movement. The Mupe Bay oil sand.]

West, I.M. 1979. Sedimentary Environments and Diagenesis of Purbeck Strata (Upper Jurassic - Lower Cretaceous) of Dorset, U.K. Unpublished Ph.D. Thesis, Southampton University, 181 p.

West, I.M., 1979. Review of evaporite diagenesis in the Purbeck Formation of southern England. Symposium: Sedimentation Jurassique W. Europeen. A.S.F. Publication Speciale, No.1, Mars 1979. 407-416.

West, I. M. 1992. Contribution on the Purbeck Formation in: Cope, J.C.W., Ingham, J.K. and Rawson, P.F. (editor). 1992. Atlas of Palaeogeography and Lithofacies. Geological Society of London.

West, I.M. 1965. Macrocell structure and enterolithic veins in British Purbeck gypsum and anhydrite. Proceedings of the Yorkshire Geological Society, 35, 47-58. Abstract: A nodular structure, here termed "macrocell structure" [nodular or chicken-wire structure] , is commonly associated with enterolithic veins in the British Purbeck gypsum and anhydrite. The veins and macrocell structure preceded the brecciation that gave rise to the Broken Beds and were present in early secondary anhydrite. Both structures probably originated when primary gypsum was undergoing compaction before the lithification of the associated marl, and have not resulted from hydration of anhydrite. A sequence of diagenesis for Purbeck calcium sulphate with macrocell structure is established, comparable to that previously elaborated [West, 1964a] for the calcium sulphate with [the microscopic] net-texture. Similar features are present in other calcium sulphate deposits.

West, I.M., 1969. Contribution in International Field Symposium on the British Jurassic; Guide for Dorset and South Somerset. Ed. H.S. Torrens, A60-61.

West, I.M. 1973. Vanished evaporites - significance of strontium minerals. Journal of Sedimentary Petrology, 43, 278-279. [On indicators of former evaporites such celestite and associated lutecite, the oblique-extinguishing variety of chalcedony; also length-slow chalcedony - quartzine etc.] Extracts: 'In a recent paper, Folk and Pittman (1971) have clearly indicated the importance of lutecite and quartzine varieties of chalcedony as evidence for the former presence of evaporites. Although lutecite has been successfully employed by the present writer for the detection of former gypsum deposits removed by dissolution (West, 1964; West, Brandon and Smith, 1968), confirmatory evidence is usually necessary. Fortunately, those processes which cause the removal of evaporites in solution frequently also result in their partial replacement by other minerals. Groundwater with bicarbonate ions may partly convert calcium sulphate deposits to calcium carbonate before dissolution of any remaining gypsum. Examples of such calcitised evaporites have been described by West (1964), Shearman and Fuller (1969) and other authors. In a dolomitic succession the calcitic nature of such replacements may be conspicuous. Pseudomorphs, relics of anhydrite in euhedral quartz crystals, and traces of net-texture (West, 1964) or nodular structure (West, 1965) may be present in any replacements or residues of dissolved evaporites. A positive indication of the former presence of calcium sulphate is the occurrence of celestite. This mineral is rarely found in sedimentary deposits other than evaporites, replaced evaporites or insoluble residues of evaporites. The related mineral barite is not so restricted. Associations of celestite with present or former evaporites have been described by Lacroix (1897), Zaritsky (1961), West (1964), West, Brandon and Smith (1968) and many other authors. Celestite is, in most cases, formed by the replacement of gypsum or anydrite; it is much less soluble than those minerals. It is usually formed by the selective removal of strontium ions from groundwater by reaction with deposits of calcium sulphate. Water containing a large proportion of calcium ions and a small proportion of strontium ions most commonly exists where limestone deposits occur in proximity. Celestite beds of appreciable thickness may be thus formed, particularly at the upper and lower boundaries of gypsum or anhydrite deposits. Such diagenetic formation of celestite is most favoured where there is appreciable flow of groundwater. Continuing diagenesis in a bicarbonate-rich environment may convert celestite to calciostrontianite (Salter and West, 1965). Smaller scale occurrences of celestite may be produced by a similar mechanism where gypsum veins have penetrated into limestone... Thus, there are many criteria for indicating the former presence of evaporites and it is wise to employ at least two. The occurrence of strontium minerals together with length-slow chalcedony [and/or lutecite] provides reliable evidence for the former presence of evaporites.'

West, I.M. 1974. Evaporite diagenesis in the Lower Purbeck Beds of Dorset. Reprinted in Kirkland and Evans (Ed.): Marine Evaporites, Origin, Diagenesis and Geochemistry. Benchmark Papers in Geology. [See West, 1964] Abstract: Five stages have been determined in the diagenetic history of the calcium sulphate beds of Lower Purbeck age in Dorset, particularly by reference to abundant pseudomorphs and other relict textures and structures preserved in late-formed gypsum and in secondary silica and calcite. The weight of the overburden is thought to have controlled the changes. Occurrences are described of minerals, including celestite, calciostrontianite, lutecite and quartz remaining after the removal in solution of gypsum. A description is also given of secondary limestones which occur particularly in the Caps and Broken Beds. They are shown to be almost entirely replacements of original sulphate deposits.

West, I.M. 1975. Evaporites and associated sediments of the basal Purbeck Formation (Upper Jurassic) of Dorset. Proceedings of the Geologists' Association, London, 86, 205-225. By Ian Michael West of Southampton University. Abstract: Four facies of limestones, each with particular contents of calcitised evaporites and of skeletal debris were recognised. They are compared with sediments of modern evaporite-depositing environments. The lowermost limestones, stromatolitic and pelletoid with foraminifera, probably originated in intertidal to shallow subtidal, moderately hypersaline, water. Overlying pelletoid limestones with algal-mats and some gypsum are products of high-intertidal flats. The main evaporite beds were originally gypsum, probably formed in supratidal to intertidal, very hypersaline, palaeoenvironments. The gypsum was converted to anhydrite and later brecciated in part, forming the Broken Beds. Extensive calcitisation produced porous unfossiliferous limestones. Ostracodal limestones above probably originated in shallow, only moderately hypersaline water. All the basal Purbeck strata were formed in and around a large shallow gulf with extensive tidal flats and with water of varying but predominantly high salinities. At times of uplift, thin soils developed on the former margins of the gulf. Forests were able to exist there because, although the area was within the semi-arid zone, it was probably very near to the boundary of the warm-temperate zone. [End of Abstract.] [Additional notes on topics discussed: Palaeosalinity origins of the basal Purbeck facies and lateral correlation. Mostly hypersaline to varying extents, including the stromatolite horizons. Fossil trees 'pickled' in a salt lake. Details of the basal Purbeck strata at all the main localities, studied petrographically. Depositional environments of the dirt beds and marls. Palaeoenvironmental significance of sedimentary cyles. Thickness variations of the facies. Relationship of the Broken Beds to the evaporitic facies. Local uplift. Penecontemporaneous fault movement. The Mupe Bay oil sand. Perryfield Quarry succession on the Isle of Portland.]

West, I.M. 1979. Sedimentary Environments and Diagenesis of Purbeck Strata (Upper Jurassic - Lower Cretaceous) of Dorset, U.K. Unpublished Ph.D. Thesis, Southampton University, 181 p. Abstract: Twelve papers, notes and a contribution to a book, all either published or accepted for publication, constitute this thesis. All parts of the classic, shallow-water, schizohaline Purbeck Formation of the type area are discussed but emphasis is on Lower Purbeck evaporites. Diagenesis of these involved much conversion of initial small lenticular crystals of gypsum to anhydrite with net-texture. The anhydrite was extensively replaced by calcite and celestite in the Broken Beds, a tectonic evaporite breccia at the base of the Purbecks. Evaporites were almost completely lost in solution from this breccia leaving characteristic relics of "vanished evaporites". Elsewhere, in the more argillaceous parts of the formation the sulphate remains, mainly as porphyrotopic secondary gypsum. Nodules and enterolithic veins are abundant in both the calcium sulphate and in the replacements. The similarity to those in Holocene sabkhas of the Trucial Coast (Shearman, 1966) suggested an origin on supratidal sabkhas, but there is a lack of desert sediments and instead the evaporites are interbedded with forest soils. Analogous Carboniferous evaporites show evidence of sabkha origins but no sign of desert conditions [West, Brandon and Smith, 1968. A tidal flat evaporitic facies in the Visean of Ireland. Journal of Sedimentary Petrology, 38, 1079-1093.]. New evidence has come from sabkhas in Northern Egypt where gypsum nodules develop in partly vegetated environment, dry but not excessively so, and supports other evidence for a semi-arid origin for the Lower Purbeck evaporites [West, Ali and Hilmy. 1979. Primary gypsum nodules in a modern sabkha on the Mediterranean coast of Egypt. Geology, 7, 354-358.]. The relatively dry climate was temporary and facies of higher parts of the Purbecks seem to result from sub-humid conditions. Throughout the formation lagoonal, 'intertidal' and supratidal deposits can be recognised but in the Middle and Upper Purbecks the lagoonal sediments have abundant brackish shelly faunas and, there, 'tidal-flat' deposits consist of shell-sand with dinosaur footprints but usually without evaporites. Progressively the proportion of land-derived clastics such as kaolinite and quartz sand increases as the continental Wealden is approached and final Purbeck sediments contain debris eroded from the underlying Portland Stone Formation, then uplifted at the western margin of the basin.

West, I.M. 1979. Review of evaporite diagenesis in the Purbeck Formation of Southern England. Symposium on: Sedimentation Jurassique W. European. ASF Publication Speciale, No. 1, 407-415.

West, I.M., Shearman, D.J. and Pugh, M.E. 1969. Whitsun Field Meeting in the Weymouth Area, 1966. Proceedings of the Geologists' Association, 80, 331-340.
.
Woodward , H.B. 1907b. Stanford's Geological Atlas of Great Britain and Ireland; with Plates of Characteristic Fossils. Preceded by descriptions of the geological structure of Great Britain and Ireland and their counties; and of the features observable along the principal lines of railway. Edward Stanford, London. Pp 189 & Plates.

[end of Purbeck Section]

Go back to top

.

8. Quaternary Features - Dolines, Solution-Pipes etc.
.
Cope , J.C.W. 1974. Vertical pipes in the Dorset Chalk. Proceedings of the Dorset Natural History and Archaeological Society, 95, p. 105.

Go back to top

9. Safety, Rock Falls etc.

There is some literature on this subject regarding Lulworth Cove which is not listed separately here. For a brief general overview see Lee, 1992 . In particular, for Black Rocks see Anonymous, 1957 . Please see also the footnote attached to this which points out that risks at Lulworth Cove are not higher than elsewhere, and that provided sensible care is taken, it would be wrong to get an exaggerated impression of hazards. For southeast side of Lulworth Cove see Anonymous, 1977a , Anonymous, 1977b . For Durdle Door see Anonymous, 1977c and Lee, 1992 .

Go back to top

[end of Safety Section]

Go back to top

10. Structural Geology and Tectonics
.
Bevan , T.G. 1985. A reinterpretation of fault systems in the Upper Cretaceous rocks of the Dorset coast, England. Proceedings of the Geologists' Association, London, 96, 337-342. Mesofault systems in the Upper Cretaceous rocks of the steep limb of the Purbeck monocline are reinterpretated by analysing their geometry with reference to the orientation of sedimentary layers. As a consequence of using layering as a datum rather than the horizontal, the five original groups of mesofaults, previously recognised by Arkell and Phillips, have been condensed into two sets of conjugate extension faults. These faults are symmetrically arranged about the layering, the dip of which varies from vertical to steeply inclined. Mesofaults previously considered to have been generated during a complicated history of thrusting, related to the tightening of the synformal bend of the monocline and horizontal compression, are reinterpreted as being the result of layer-parallel extension during flexuring. Thus they are accomodation structures formed during the development of the monocline, itself related to drape over reactivated Jurassic growth faults during N-S shortening. South-dipping reverse macrofaults are reinterpreted as being the continuation to the surface of the reactivated Jurassic growth-faults, whilst north-dipping reverse macrofaults are interpreted as being antithetic to these reactivated faults. A tectonic implication arising from the proposed kinematic classification of the mesofaults is that they can be perceived as being the product of stretching of a steep fold limb during flexuring, rather than being related to several phases of horizontal compression.
.
Nowell , D.A.G. 1996. Faults in the Purbeck - Isle of Wight monocline. Proceedings of the Geologists' Association, London, 106, 145-150. Faults at Arish Mell and Corfe Castle in Dorset and at Freshwater Bay and Shide, Newport on the Isle of Wight cut the Purbeck - Isle of Wight monocline. Evidence for these hitherto unrecognised faults is based on outcrop displacement and differences in: (a) outcrop widths either side of the faults; (b) strike and dip of the strata; and (c) the direction of the axis of the monocline. These faults developed above offsets in large normal faults beneath the subsequent monocline and were active growth faults during deposition of the Chalk. During the later Alpine tectonic episode which formed the Purbeck - Isle of Wight monocline these faults were reactivated so displacing the boundary between the Chalk and the Reading Beds. The faults locally weakened the chalk ridge and allowed south to north drainage to develop through the ridge.
Nowell, D.A.G. 1997a. Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting. Proceedings of the Geologists' Association, 108, 257-268. Pre-Albian northwest-southeast faults have been inferred along the coast between Durdle Door and Worbarrow Tout. From the westward increase in the thickness of Wealden units between Mupe Bay and Lulworth Cove followed by the dramatic thinning across the cove it is suggested that these faults were synsedimentary growth faults during the early Cretaceous. Also the Wealden is shown to contain two main quartz grit bands, only the lower of which is seen in Lulworth Cove due to increasing westwards Albian erosion which mainly explains the westward thinning of the Wealden. These faults may have continued to be active throughout the rest of the Cretaceous. During the later Alpine formation of the Purbeck monocline, southward dipping faults also developed. Their alignment may have been controlled by the reactivated northwest-southeast faults. To the west of Lulworth Cove much of the succession between the Portland Stone and the Chalk is cut out by these east-west thrusts.

Nowell, D.A.G. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): reply. Proceedings of the Geologists' Association, 109, 239-240. This is a reply to a discussion of Nowell's 1997a paper by Jon Radley of Reading University. Radley, J.D. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): comment. Proceedings of the Geologists' Association, 109, 237-238.

Nowell, D.A.G. 1997b. The geology of Lulworth Cove, Dorset. Geology Today, 13, 207-210.
.
Phillips , W.J. 1964. The structures in the Jurassic and Cretaceous rocks on the Dorset coast between White Nothe and Mupe Bay. Proceedings of the Geologists' Association, London, 75, 373-405

Radley, J.D. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): comment. Proceedings of the Geologists' Association, 109, 237-238. This is a discussion of the paper - Nowell, D.A.G. 1997a. Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting. Proceedings of the Geologists' Association, 108, 257-268. Radley criticises the matter of Wealden correlation. He questions the use of lumps of lignite as marking an identifiable horizon. A major problem is the correctness or not of the correlation of quartz grits put forward by Nowell, which is against the usual view and that held by Radley. The recognisable character of the Coarse Quartz Grit is argued by Radley who suggests that it may be isochronous. The Mupe Bay conglomeratic oil sand (or "Oily Boulder Bed") is also referred to, although there has been separate controversy over this (Miles, J.A., Downes, C.J. and Cook, S.E. 1992 - see Mupe Bay Field Guide )

[end of Structural Section]

Go back to top

. 11. Upper Greensand (Albian)


.
Drummond , P.V.O., 1970. The Mid-Dorset swell: evidence of Albian-Cenomanian movements in Wessex. Proceedings of the Geologists' Association, 81, 679-716. Abstract: The Upper Cretaceous succession of Wessex was intermittently interrupted by periods of mild movements which were responsible for the numerous diastems within the Upper Albian-Cenomanian sequence. Important phases of activity involving the slight elevation of small periclines occurred at the close of the Mortoniceras inflalum Zone, Lower and Middle Cenomanian times. Of particular importance was a persistent line of periclines coincident with a north-west-south-east trending belt of thinning within the Upper Albian and Cenomanian sequences extending from central Dorset to the Isle of Purbeck and on toward the Isle of Wight. This structure (the Mid-Dorset Swell) had a profound effect upon Vraconian-Cenomanian sedimentation, causing extensive reworking, condensation and erosion of deposits over its crest, and separated a south-western shallow-water limestone province (the Wessex Shelf) from a north-eastern deeper-water chalk-greensand province (the Wessex Trough). The Mid-Dorset Swell was responsible for the isolation of the Vraconian Chert Beds into three distinct basins, for the restriction of Cenomanian Limestone sensu lato to the Wessex Shelf, and for confining the Cenomanian Chalk Marl within the Wessex Trough. The progressive overlap of the Chalk Marl up the eastern flank of the Mid- Dorset Swell enhances the stratigraphical break between the Vraconian and the Cenomanian, until eventually the Grey Chalk oversteps on to M. inflatum Zone greensands along the crest of the Swell. During the Upper Cenomanian the Mid-Dorset Swell was dormant and uniform Grey Chalk, subject only to regional south-westerly shallowing, was deposited over most of the region. Across the Wessex Shelf the Grey Chalk has a condensed Basement-bed of fossiliferous pebbly Middle and Lower Cenomanian debris resting on the waterworn surface of the top Upper Greensand. The Upper Cenomanian ended with renewed movements which rejuvenated the Mid-Dorset Swell and caused some erosion of the Grey Chalk prior to deposition of the Turonian. [This is a key paper for understanding Late Kimmerian movements in the Lulworth area.]
.
Kennedy , W.J. 1970. A correlation of the uppermost Albian and the Cenomanian of south-west England. Proceedings of the Geologists Association, 81, 613-677.
.
Owen , H.G. 1971a. Middle Albian stratigraphy in the Anglo-Paris basin. Bulletin of the British Museum Natural History (Geology), Supplement, 8, 1-164
.
Rawson , P.F., Curry, D., Dilley, F.C., Hancock, J.M., Kennedys, W.J., Neale, J.W., Wood, C.J. and Worssam , B.C. 1978. A correlation of Cretaceous rocks in the British Isles. Special Report of the Geological Society of London, 9, 70 pp
.
Sellwood , B.W., Durkin, M.K. and Kennedy, W.J. 1970. Field Meeting on the Jurassic and Cretaceous rocks of Wessex. Proceedings of the Geologists' Association, 81, 715-732.
.
Tresize, G.R. 1960. Aspects of the lithology of the Wessex Upper Greensand. Proceedings of the Geologists' Association, 71, 316-339.

Go back to top

. 12. Wealden
.
Allen , P. 1972. Wealden detrital tourmaline: implications for northwestern Europe. Journal of the Geological Society, 128, 273-294. Abstract: Wealden detritus in S. England and N.W. France suggests ultimate derivation from an ancient complex. This had affinities with present-day Cornubia, Armorica and NW Iberia, which apparently represents its relict flanks. Westward, lay a Cadomian-Caledonian core. Repeated tourmalinizations occurred from pre-Cambrian times onward. These were postdeformational and may have followed separate orogenies. Geographically the massif probably focussed on what is now the continental margin, over the Southwestern Approaches. Structurally, it was the Cadomian-Hercynian-Galician-Caledonian convergence. Eastwards the hills diverged to encompass a lowland depression, divided into northern and southern basins by the Cornubian island. After the first sediment arrived in the ?Permian there were important fluctuations of supply and composition during the late Trias/early Jurassic, late Jurassic/early Cretaceous and Hasting Beds/Weald Clay. These may have been related to movements of the massif generated by changes in North Atlantic spreading rates and opening of Biscay.
.
Garden , I.R. 1987. The Provenence of Upper Jurassic and Lower Cretaceous Coarse Grained Detritus in Southern Britain and Normandy. Unpublished Ph.D. Thesis. Department of Geology, University of Southampton. One volume of 410 pages plus 50 pages of Appendices. 63 monochrome plates. September, 1987. By Ian Ross Garden (supervisor - IMW). Abstract: The provenance of coarse-grained detritus from the Upper Jurassic Corallian Group and Lydite Beds and Lower Cretaceous Purbeck Formation, Spilsby Sandstone Formation, Wealden Group, Claxby Ironstone Formation, Lower Greensand Group and Gault Clay Formation of southern Britain and Normandy (northern France) has been studied. The coarse-grained detrital suites contain extrabasinal phenoclasts derived from Palaeozoic and Precambrian massifs, and Jurassic and Cretaceous clasts from intrabasinal highs. The former assemblage is dominated by chert derived from Carboniferous limestone and quartz. Sandstones, radiolarian cherts and tourmalinites are locally abundant. The intrabasinal detritus is composed principally of chert, phosphorite and ironstone...Progressive changes in phenoclast suites provide a means for studying both local variations associated with uplift of intrabasinal structures and regional variations associated with basin development...Local variations in the intrabasinal pebbles suites of Dorset provide evidence of major fault-associated uplift of the South Dorset High during earliest Cretaceous times. Post-faulting subsidence resulted in marine onlap and further erosion of the structure. The South Dorset High is structurally similar to other fault-associated highs in the Wessex and Paris Basins, and it is probable that they have undergone extensive Early Cretaceous uplift in conjunction with basin rifting... The Upper Jurassic and Lower Cretaceous phenoclast suites of southern Britain and Normandy are separable into three stratigraphical assemblages. The oldest assemblage, Oxfordian to Early Berriasian in age, is dominated by chert derived from Carboniferous limestones. The two younger assemblages (Late Berriasian to Barremian and Aptian to Middle Albian) are distinguished by a generally higher proportion of quartz. The Aptian to Middle Albian phenoclast assemblage is separable into two subassemblages (Aptian, and Lower to Middle Albian) and the latter shows lateral changes which enable it to be subdivided into three geographical provinces and five subprovinces... In the Wessex Basin, a change from chert-dominated to quartz-dominated phenoclast suites occcurred at the beginning of the Cretaceous System. This resulted from uplift and erosion of the marginal massifs adjacent to the rifting basin. On the East Midland Shelf, however, modifications in the detrital suites did not occur until mid-Cretaceous times. The delayed change was caused by limited uplift of the adjacent massifs during Early Cretaceous times and reworking of slightly older pebble beds on the shelf. The marginal highs were then uplifted and eroded during the mid-Cretaceous phase of thermal subsidence in the Southern North Sea Basin. [End of Author's Abstract]

Notes: See Appendix 1, page x etc. for percentage composition of Wealden pebble beds of the Lulworth area. Eg. Lulworth Cove - decreasing abundance - (for -3.5 phi) - opaque quartz - 28, radiolarian chert - 25, quartz plus tourmaline - 24, translucent quartz - 13, fibrous quartz - 10. Similar information given for two size fractions at Durdle Door, Mupe Bay and Worbarrow Bay. Data also for the Gault in this area. Descriptions are given of reworked Portland and Purbeck detritus in the Wealden, Lower Greensand and Gault of Dorset and the Isle of Wight.
.
Parker , A. 1972. Jarosite in Wealden oil-sand from Lulworth Cove. Journal of the Geological Society, London, 128, 289-290.
.
Radley , J.D. 1998. "Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting" by Nowell (1997): comment. Proceedings of the Geologists' Association, London, 109, 237-238. This is a discussion of the paper - Nowell, D.A.G. 1997a. Structures affecting the coast around Lulworth Cove, Dorset and syn-sedimentary Wealden faulting. Proceedings of the Geologists' Association, 108, 257-268. Radley criticises the matter of Wealden correlation. He questions the use of lumps of lignite as marking an identifiable horizon. A major problem is the correctness or not of the correlation of quartz grits put forward by Nowell, which is against the usual view and that held by Radley. The recognisable character of the Coarse Quartz Grit is argued by Radley who suggests that it may be isochronous. The Mupe Bay conglomeratic oil sand (or "Oily Boulder Bed") is also referred to, although there has been separate controversy over this (Miles, J.A., Downes, C.J. and Cook, S.E. 1992 - see Mupe Bay Field Guide )
.
Strahan , A. 1898. The Geology of the Isle of Purbeck and Weymouth. Memoirs of the Geological Survey. Her Majesty's Stationery Office, London. 278 pages with a map.

Go back to top

|Home and List of Webpages |Lulworth Cove |Fossil Forest | Dungy Head | Durdle Door | Lulworth Bibliography |

Go back to top

Copyright © 2013 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 text may be used for non-commercial academic purposes, including field trip handouts, lectures, student projects, dissertations etc, providing source is acknowledged. No permission can be given for reproduction of any images of the Lulworth Cove area in books or in other websites, for special reasons.

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.

Go back to top

Dr Ian West, author of these webpages

Webpage - written and produced by:


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

.

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.



.