Late Glacial and Holocene Palaeolake History of the ultima Esperanza Region of Southern Patagonia

We undertook multi-proxy analyses on two sediment cores from Lago Pato, a small lake basin at 51 degrees S topographically separated from Lago del Toro in Torres del Paine (TdP), to provide insights into glacier dynamics and lake-level change in the TdP and ultima Esperanza region over the last similar to 30,000 cal a BP (30 ka). Lago Pato is situated in a region overridden by the Southern Patagonian Ice Field during the Last Glacial and in a transitional climatic zone of Southern Patagonia sensitive to seasonal- to millennial-scale changes in the Southern Hemisphere Westerly Winds (SWW). Results show that a deep ice-dammed and enlarged palaeolake encompassed Lago del Toro and Lago Pato c. 30-20 ka after the ice had retreated from local-Last Glacial Maximum (l-LGM) limits at c. 48-34 ka and during the build-up to the global-Last Glacial Maximum (g-LGM), c. 26-19 ka. Gaps in both sediment records between c. 20-13.4 ka and c. 20-10 ka suggest hiatuses in sediment accumulation during the g-LGM and Antarctic Cold Reversal (ACR) readvances and/or removal by lake lowering or flushing during the Late Glacial-early Holocene. The palaeolake level dropped from >100 m a.s.l. to similar to 40-50 m a.s.l. towards the end of the ACR c. 13.4-13.0 ka, creating a shallower glaciolacustrine environment dammed by an ice tongue in the Estancia Puerto Consuelo-ultima Esperanza fjord. Further lowering of the enlarged palaeolake level occurred when the ice thinned to