Antarctic Ice Sheet dynamics through the Neogene from evidence in the ANDRILLâ•fiMcMurdo Ice Shelf Project drillcore (AND-1B)

ANDRILL completed its first season in 2006-07 drilling AND-1B through the McMurdo Ice Shelf (MIS) to a depth of 1,285m below the sea floor, a record for Antarctic margin drilling, with 99% recovery. The alternating glacial-interglacial sediment packages interbedded with volcanics provide a uniquely detailed record of Antarctic glacial and climatic change through the Neogene. This paper summarizes the initial characterization of lithofacies and syndepositional structures relevant to understanding the regime and dynamics of past Antarctic ice sheets based on the ANDRILL-MIS Initial Report. Results suggest that the Antarctic Ice Sheet was relatively cold with little basal melting in the middle Miocene and Pleistocene times but under a more dynamic and warmer polythermal glacial regime in late Miocene and Pliocene times. More detailed research, including a modeling component, is planned in order to understand the dynamics under these different regimes.