Early deglaciation and paleolake history of Río Cisnes Glacier, Patagonian Ice Sheet (44°S). Issue 1 (31st October 2018)

• Record Type: Journal Article
• Authors: García, Juan-Luis; Maldonado, Antonio; de Porras, María Eugenia; Nuevo Delaunay, Amalia; Reyes, Omar; Ebensperger, Claudia A.; Binnie, Steven A.; Lüthgens, Christopher; Méndez, César
• Is Part Of: Quaternary research. Volume 91:Issue 1(2019)
• Page Start: 194
• Page End: 217
• Publication Date: 2018-10-31
• Subjects: last termination, -- last glacial-interglacial transition, -- last deglaciation, -- Patagonia, Patagonian ice sheet, -- paleolakes, -- glacial geomorphology, -- 10Be dating, -- OSL dating, -- 14C dating; Geology, Stratigraphic -- Quaternary -- Periodicals; Glacial epoch -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; Époque glaciaire -- Périodiques; Geology, Stratigraphic; Glacial epoch; Quaternary Geologic Period; Electronic journals; Periodicals; 551.79
• DOI: 10.1017/qua.2018.93
• Languages: English
• ISSNs: 0033-5894

Abstract

Abstract: 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 14 C, 10 Be, 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.