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The University of Southampton
Ocean and Earth Science, National Oceanography Centre Southampton

Research project: From icebergs to ice sheets; provenance of ice rafted sediments

Currently Active: 
Yes

Sea level rise is arguable the most important consequence of anthropogenic climate change. However, accurate forecasting of the future magnitude of sea-level change is difficult because current numerical climate models lack the capacity to accurately model the melting and growth of continental ice sheets.  This complicates long-range sea-level projections, because the retreat of continental ice sheets will increasingly contribute to sea-level rise as the 21st century progresses.  New methods and data are therefore urgently needed to test the accuracy of existing ice sheet models and to provide test beds for ice sheet model development.  We aim to do this by reconstructing ice sheet coverage in the geological past. 

The geology of Greenland is geographically distinct allowing iceberg source terranes to be identified geochemically.
The Geology of Greenland

Key Questions

  • How much does the Greenland Ice sheet (GrIS) retreat during warm intervals of the geological past? How might it respond to future warming?
  • Can we use geological data to test ice sheet models of warmer climate states? Can we improve models for the future state of the GrIS?
  • How is the growth and decay of circum-North Atlantic Ice sheets related to CO2 change in the past? What can this tell us about the future?
Varying ice sheet model parameters results (left) in the same modern configuration of the Greenland Ice sheet (top) but different configurations for the future (mid) and Mid-Pliocene (bottom)
Ice sheet model parameters

How do we do it?

  • Icebergs calved from the marine margins of continental ice sheets contain sediment eroded from the sub-glacial continent.
  • The icebergs melt in the open ocean and this sediment is deposited as ice-rafted debris (IRD) on the sea-floor, being incorporated into deep ocean sediments. 
  • Due to differing geological histories, the rocks beneath the ice sheets often have unique geochemical and isotopic fingerprints. 
  • We use state of the art analytical techniques to analyse the isotopic composition and age of individual grains of IRD (e.g. feldspar and amphibole) which can then be married up to the appropriate source region.
  • We can thus determine which  parts of the continent were covered in ice sheets in the past.  
Iceberg (Source: C Storey)
Iceberg (Source: C Storey)

Key Contacts

Dr Gavin Foster

 

(Source: Dave Hodell)
Diatoms and Grains

Related Project Pages

Descent into the Icehouse

Past and Present Ocean Acidification

How hot is it going to get?

PhDs and Other Opportunities

Visit GSNOCS

Associated research themes

Past Present and Future Environmental Change

Related research groups

Geochemistry
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