Anna E. Nelson1, John L. Smellie1, Michael J. Hambrey2, Mark Williams3, Ulrich Salzmann1, and Maryline J. Vautravers1. (1) Geological Sciences Division, British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, United Kingdom, (2) Institute of Geography & Earth Sciences, University of Wales, Ceredigion, Aberystwyth, United Kingdom, (3) Department of Geology, University of Leicester, University Road, Leicester, United Kingdom
The parameters of the Cenozoic Antarctic Ice Sheet (AIS) are poorly known and contentious. Our investigation of late Neogene glacial and interglacial sediments from James Ross Island will inform this debate by providing critical new data from a part of the AIS that is particularly sensitive to climatic variability. Our sedimentological analyses of the lithofacies reveal a combination of basal tills, remobilised debris flow deposits, and glaciomarine sequences. The influence of two scales of ice masses is recognised: a regional-scale Antarctic Peninsula ice sheet and a local ice cap. The contact relationships between the glacial sediment and overlying volcanic rocks indicate that glaciation and volcanism were essentially contemporaneous, and the volcanic units have provided an excellent chronology for the glaciations. A polythermal glacial regime is suggested for the Neogene glacial cover on James Ross Island, with conditions similar to the high Arctic today.
[Manuscript]
