Sediment drifts in Lago Castor (Chilean Patagonia) reflect changes in the strength of the Southern Hemisphere Westerly winds since the Last Glacial Maximum

Lago Castor (45.6°S; 71.8°W) is located within the postglacial pathway of the core of the Southern Hemisphere Westerly winds, which migrated from~42°S during the LGM to ~52°S at present. During two field expeditions (2009-2011) a network of high-resolution reflection-seismic profiles of the lake infill was acquired and a 15 m long composite sediment core was retrieved. The combination of the seismic stratigraphy and the sediment core lithology shows that the lower units were deposited in a proglacial environment, while the upper units (younger than 18.3 kyr BP) were influenced by bottom currents counteracting currents of surface waters driven by the Southern Hemisphere Westerlies. We conclude that sediment drifts constitute a good and relatively poorly investigated proxy for Westerly wind strength reconstructions.