Geomorphology and 10Be chronology of the Last Glacial Maximum and deglaciation in northeastern Patagonia, 43°S-71°W

In southern South America, well-dated glacial geomorphological records constrain the last cycle across much of former Patagonian Ice Sheet, but its northeastern sector remains comparatively understudied and unconstrained. This knowledge gap inhibits our understanding timing maximum glacier extent, duration maximum, onset deglaciation, whether asynchronies exist in behaviour ice sheet with latitude, or location (east west) relative to divide. Robust reconstructions from this region are thus required comprehend mechanisms driving Quaternary glaciations at mid-latitudes. We here present 10Be surface exposure ages five moraine sets along Bayesian age modelling reconstruct a detailed chronology Last Glacial Maximum expansions Río Corcovado glacier, major conduit northern Patagonia. find that outlet reached expansion during global ∼26.5–26 ka, least four subsequent advances/stillstands occurred over 2–3 ka period, ∼22.5–22 ∼22–21.5 ∼21–20.5 20–19.5 ka. The local deglaciation likely between 20 19 Contrary several other glaciers, including similar latitudes on western side Andes, we no evidence for MIS 3/4 advances. Exposure dating palaeo-shoreline cobbles reconstructing proglacial lake formation drainage shifts studied indicate three glaciolacustrine phases characterised by Atlantic-directed drainage. Phase one 26.4 ± 1.4 phase two ∼21 ∼19 ∼16.3 ice-moulded bedrock interior cordillera indicates disintegration Sheet Atlantic-Pacific reversal had were coeval Antarctic mid-latitude atmospheric oceanic cooling signals, out summer insolation intensity. Our results 1–2 earlier than northwestern, central eastern southeastern which could high regional sensitivity warming drying Varas interstade (∼22.5–19.5 ka).