Late-glacial grounding line retreat in the northern Ross Sea, Antarctica

We present geochronologic constraints on the timing of grounding line retreat in the western Ross Sea, Antarctica, based on changes in ice-surface elevation of glaciers in northern Victoria Land. We constructed ice-surface lowering histories using C-14 surface exposure dating at Tucker and Aviator Glaciers, and the timing of retreat at Terra Nova Bay. Our record demonstrates that thinning of 290-380 m occurred since the Last Glacial Maximum at Tucker Glacier, and at least 250 m of thinning occurred at Aviator Glacier. We observed no significant thinning prior to or during meltwater pulse la. Maximum rates of thinning occurred between 13.6 and 12.4 ka at Tucker Glacier, and after 11.4 ka at Aviator Glacier. At both locations, ice surfaces were near their present elevations by ca. 7.5 ka. Ice-surface lowering in northern Victoria Land was a linear response to sea-level rise during deglaciation and provides a contrast to the nonlinear response of glaciers to the south in the presence of relatively stable sea level.