Browsing by Author "Garcia, Juan L."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    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.
  • Thumbnail Image
    Item
    LATE PLEISTOCENE ICE FLUCTUATIONS AND GLACIAL GEOMORPHOLOGY OF THE ARCHIPIELAGO DE CHILOE, SOUTHERN CHILE
    (TAYLOR & FRANCIS LTD, 2012) Garcia, Juan L.
    Most of the last glacial maximum (LGM) glacier record west of the southern Andes (40-55 degrees S) is today submerged under the Pacific Ocean and therefore the Archipielago de Chiloe (42-43 degrees S) provides an unusual opportunity to study local sediment and landform associations to help understand paleoglacial features of the former Patagonian ice sheet (PIS). In this context, this work presents the first comprehensive glacial geomorphologic mapping of the central region of the Archipielago de Chiloe, which is located in a transitional geomorphic region between the Chilean Lake District (CLD, 39-41 degrees S, 73 degrees W) and northwest Patagonia ( 43-48 degrees S, 74 degrees W).