Browsing by Author "Vega, Rodrigo M."

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    A composite 10Be, IR-50 and 14C chronology of the pre-Last Glacial Maximum (LGM) full ice extent of the western Patagonian Ice Sheet on the Isla de Chiloe, south Chile (42° S)
    (2021) Garcia, Juan-Luis; Luthgens, Christopher; Vega, Rodrigo M.; Rodes, Angel; Hein, Andrew S.; Binnie, Steven A.
    Unanswered questions about the glacier and climate history preceding the global Last Glacial Maximum (LGM) in the southern temperate latitudes remain. The Marine Isotope Stage (MIS) 3 is normally understood as a global interstadial period; nonetheless its climate was punctuated by conspicuous variability, and its signature has not been resolved beyond the polar realms. In this paper, we compile a Be-10 depth profile, single grain infrared (IR) stimulated luminescence dating and C-14 samples to derive a new glacier record for the principal outwash plain complex, deposited by the western Patagonian Ice Sheet (PIS) during the last glacial period (Llanquihue Glaciation) on the Isla de Chiloe, southern Chile (42 degrees S). In this region, the Golfo de Corcovado Ice Lobe left a distinct geomorphic and stratigraphic imprint, suitable for reconstructing former ice dynamics and timing of past climate change. Our data indicate that maximum glaciation occurred by 57.8 +/- 4.7 ka without reaching the Pacific Ocean coast. Ice readavanced and buttressed against the eastern side of the Cordillera de la Costa again by 26.0 +/- 2.9 ka. Our data further support the notion of a large ice extent during parts of the MIS 3 in Patagonia and New Zealand but appear to contradict near contemporaneous interstadial evidence in the southern midlatitudes, including Chiloe. We propose that the PIS expanded to its full-glacial Llanquihue moraines, recording a rapid response of southern mountain glaciers to the millennial-scale climate stadials that punctuated the MIS 3 at the poles and elsewhere.
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    Deglacial ice-marginal glaciolacustrine environments and structural moraine building in Torres del Paine, Chilean southern Patagonia
    (2015) García B., Juan Luis; Strelin, Jorge A.; Vega, Rodrigo M.; Hall, Brenda L.; Stern, Charles R.
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    Glacier expansion in southern Patagonia throughout the Antarctic cold reversal
    (GEOLOGICAL SOC AMER, INC, 2012) Garcia, Juan L.; Kaplan, Michael R.; Hall, Brenda L.; Schaefer, Joerg M.; Vega, Rodrigo M.; Schwartz, Roseanne; Finkel, Robert
    Resolving debated climate changes in the southern middle latitudes and potential teleconnections between southern temperate and polar latitudes during the last glacial-interglacial transition is required to help understand the cause of the termination of ice ages. Outlet glaciers of the Patagonian Ice Fields are primarily sensitive to atmospheric temperature and also precipitation, thus former ice margins record the extent and timing of past climate changes. 38 Be-10 exposure ages from moraines show that outlet glaciers in Torres del Paine (51 degrees S, south Patagonia, Chile) advanced during the time of the Antarctic cold reversal (ACR; ca. 14.6-12.8 ka), reaching a maximum extent by similar to 14,200 +/- 560 yr ago. The evidence here indicates that the South Patagonian Ice Field was responding to late glacial climate change distinctly earlier than the onset of the European Younger Dryas stadial (ca. 12.9 ka). Major glacier recession and deglaciation in the Torres del Paine region occurred by 12.5 ka and thus early in the Younger Dryas. We provide direct evidence for extensive ice in Patagonia at the very start of the ACR that agrees with atmospheric and marine records from the Southern Ocean and Antarctica. Atmospheric conditions responsible for the early late glacial expansion at Torres del Paine resulted from a climate reorganization that prompted a northern migration of the south westerly wind belt to the latitude of Torres del Paine at the onset of the ACR chronozone.