A multi-glacial cycle cosmogenic nuclide chronology of Patagonian Ice-Sheet expansions in Northeastern Patagonia (43°S)

• Main Authors: Leger, Tancrède P.M., Hein, Andrew, Rodes, Angel, Bingham, Robert, Schimmelpfennig, Irene, Fabel, Derek, Tapia, Pablo, Aster, Team
• Other Authors: Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)
• Format: Conference Object
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Orleans; Patagonia; Ice Sheet
• Online Access: https://hal.science/hal-03550463

International audience Here, we reconstruct the glacial history and chronology of a previously unstudied region of Patagonia that formerly hosted the Río Corcovado (43°S, 71°W) outlet glacier. We present a new set of cosmogenic 10Be and 26Al exposure ages from moraine boulders, ice-moulded bedrock surfaces, palaeo-shoreline surface cobbles and glaciofluvial outwash surface cobbles. This dataset completes our effort to date the entire preserved moraine record of the Río Corcovado valley: which captures at least eight distinct Pleistocene glacial events. Our results allow answering questions on the timing of maximum local ice extent during the last glacial cycle and older, mid-Pleistocene glaciations, for which few direct glacier chronologies exist in the Southern Hemisphere. The most informative cosmogenic nuclide-derived glacial chronologies with the capacity to resolve questions on interhemispheric phasing of climate change require unambiguous dating of glacial margins spanning several glacial cycles. Thus, our findings have implications for understanding Pleistocene climate fluctuations, former Southern Westerly Winds behaviour and interhemispheric climate linkages. They also provide further evidence supporting the proposed latitudinal asynchrony in the timing of Patagonian Ice Sheet expansion during the last glacial cycle and enable novel glacio-geomorphological interpretations for the region.