Soluble salt accumulations in Taylor Valley, Antarctica: Implications for paleolakes and Ross Sea Ice Sheet dynamics

Soluble salt accumulations in soils of Taylor Valley, Antarctica, provide a history of paleolakes and the advance of the Ross Sea Ice Sheet (RSIS). In western Taylor Valley, soluble salt accumulations are relatively high and are composed primarily of Na+, Ca2+, Cl-, and SO42-. In eastern Taylor Valley, soluble salt accumulations are much lower and are composed primarily of Na+ and HCO3-. Na-HCO3-rich compositions in eastern Taylor Valley are formed through leaching, calcite dissolution, and cation exchange reactions and appear to influence the chemistry of nearby streams and lakes. The data presented here support hypotheses that a lobe of the RSIS expanded into eastern Taylor Valley and dammed proglacial paleolakes. However, in contrast to previous studies, our findings indicate that the RSIS advanced deeper into Taylor Valley and that paleolakes were less extensive. By comparing soluble salt distributions across Taylor Valley, we conclude that a lobe of the RSIS filled all of eastern Taylor Valley and dammed paleolakes in western Taylor Valley up to approximately 300 m elevation. Following ice retreat, smaller paleolakes formed in both western and eastern Taylor Valley up to about 120 m elevation, with prominent still-stands controlled by the elevation of major valley thresholds. At higher elevations, soluble salt accumulations are consistent with older soils that have not been affected by the most recent RSIS advance.