Pore fluid modeling approach to identify recent meltwater signals on the west Antarctic Peninsula

Abstract

The sensitivity of sea level to melting from polar ice sheets and glaciers during recent natural and anthropogenic climate fluctuations is poorly constrained beyond the period of direct observation by satellite. We have investigated glacial meltwater events during the Anthropocene by adapting the pioneering approach of modeling trends in δ18O in the pore waters of deep-sea cores, previously used to constrain the size of ice sheets during the Last Glacial Maximum. We show that during recent warm periods, meltwater from glacier retreat drains into the coastal fjords, leaving a signature of depleted δ18O values and low Cl concentrations in the pore water profiles of rapidly accumulating sediments. Here we model such pore water profiles in a piston core to constrain the timing and magnitude of an ice sheet retreat event at Caley Glacier on the west Antarctic Peninsula, and the result is compared with local ice front movement. This approach of pore water modeling was then applied in another kasten core and tested by a series of sensitivity analyses. The results suggest that our approach may be applied in fjords of different sedimentary settings to reconstruct the glacier history and allow insight into the sensitivity of polar glaciers to abrupt warming events. Copyright 2010 by the American Geophysical Union.