Constraining past accumulation in the central Pine Island Glacier basin, West Antarctica, using radio-echo sounding

The potential dynamical instability of Pine Island Glacier, West Antarctica, has been addressed in a number of studies but information on its past remains limited. In this study we use radio-echo sounding data acquired over Pine Island Glacier to investigate past variations in accumulation pattern. In the radar dataset a distinctive pattern of layers was identied in the central part of the glacier basin. We use these layers as chronological identiers in order to construct elevation maps of the internal stratigraphy. The internal layer stratigraphy is then compared to results from a three-dimensional ice-flow model that has been forced with different accumulation scenarios. The model results indicate that the accumulation pattern is likely to have changed at least twice since the deposition of the deepest identied layer. Additional radar data linked to the Byrd Ice Core provide an approximate time-scale. This time-scale suggests that the layers were deposited at the beginning of or during the Holocene period. Thus the widespread changes occurring in the coastal extent of the West Antarctic Ice Sheet at this time could have been accompanied by changes in
accumulation pattern.