Extensive early deglaciation and paleolake history of the Río Cisnes Ice Lobe, Patagonian Ice Sheet 44°S

• Published in: Quaternary Research
• Main Authors: García, Juan Luis, Maldonado, Antonio J., de Porras, Maria Eugenia, Nuevo Delaunay, Amalia, Reyes, Omar, Ebensperger, Claudia A, Binnie, Steven A., Lüthgens Christopher, Mendez, Cesar
• Format: Article in Journal/Newspaper
• Language: English
• Published: Academic Press Inc Elsevier Science
• Subjects: 10BE DATING; 14C DATING; GLACIAL GEOMORPHOLOGY; LAST DEGLACIATION; LAST GLACIAL-INTERGLACIAL TRANSITION; LAST TERMINATION; OSL DATING; PALEOLAKES; PATAGONIA; PATAGONIAN ICE SHEET; https://purl.org/becyt/ford/1.5; https://purl.org/becyt/ford/1; Antarctic; Southern Ocean; Patagonia; West Antarctica; Argentino; Argentina; El Toqui; Antarc*; Antarctica; Ice Sheet; Sea ice
• Online Access: http://hdl.handle.net/11336/169882

The timing, structure, and landscape change during the Patagonian Ice Sheet deglaciation remains unresolved. In this article, we provide a geomorphic, stratigraphic, and geochronological deglacial record of Río Cisnes Glacier at 44°S and also from the nearby Río Ñirehuao and Río El Toqui valleys (45°S) in Chilean Patagonia. Our 14C, 10Be, and optically stimulated luminescence data indicate that after the last glacial maximum, Río Cisnes Glacier experienced ∼100 km deglaciation between >19.0 and 12.3 ka, accompanied by the formation of large glacial paleolakes. Deglaciation was interrupted by several ice readvances, and by 16.9±0.3 ka, Río Cisnes Glacier extended only ∼40% of its full glacial extent. The deglaciation of Río Cisnes Glacier and other sensitive Patagonian glaciers occurred at least 1 ka earlier than the ca. 17.8 ka normally assumed for the local termination, coincident with West Antarctic isotope records. This early deglaciation can be linked to an orbital forcing-driven decline of Southern Ocean sea ice associated with a distinct atmospheric warming that is apparent for West Antarctica through Patagonia. Fil: García, Juan Luis. Pontificia Universidad Católica de Chile; Chile Fil: Maldonado, Antonio J. Comisión Nacional de Investigación Científica y Tecnológica. Centro de Investigación Regional. Centro de Estudios en Zonas Áridas; Chile Fil: de Porras, Maria Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina. Comisión Nacional de Investigación Científica y Tecnológica. Centro de Investigación Regional. Centro de Estudios en Zonas Áridas; Chile Fil: Nuevo Delaunay, Amalia. Centro de Investigación de Ecosistemas de la Patagonia; Chile Fil: Reyes, Omar. ...