HR: 0800h
AN: GC51C-1061    [Abstracts]
TI: Late-Quaternary Glacial History of the Venezuelan Andes
AU: * Stansell, N D
EM: nas12@pitt.edu
AF: Geology and Planetary Science, University of Pittsburgh 4107 O'Hara St. Rm 200 SRCC , Pittsburgh, PA 15260 United States
AU: Abbott, M B
EM: mabbott1@pitt.edu
AF: Geology and Planetary Science, University of Pittsburgh 4107 O'Hara St. Rm 200 SRCC , Pittsburgh, PA 15260 United States
AU: Polissar, P J
EM: polissar@geo.umass.edu
AF: Department of Geosciences, Morrill Science Center University of Massachusetts, Amherst, MA 01003 United States
AU: Wolfe, A P
EM: awolfe@ualberta.ca
AF: Department of Earth and Atmospheric Sciences, University of Alberta, Edmonton, AB T6G 2E3 Canada
AU: Rull, V
EM: valenti.rull@uab.es
AF: Department de Biologia Animal, Vegetal i Ecologia, Universitat Aut•noma de Barcelona, Bellaterra, Barcelona, 08193 Spain
AU: Bezada, M
EM: mbezada@cantv.net
AF: Universidad Pedag˘gica Experimental Libertador, Departamento de Ciencias de la Tierra, Avenida Paez, El Paraˇso, Caracas, 1062 Venezuela
AB: Lake sediments and bog deposits in the Cordillera de M‚rida were used to identify and date multiple late-Pleistocene and Holocene glacial advances/retreats of varying magnitudes. Analyses include AMS radiocarbon dating, sedimentology studies, pollen and diatom assemblage investigations, magnetic susceptibility, geochemistry and stable isotope measurements (C, N, and O) on a series of cores from 7 lakes and 2 bogs. Additionally, equilibrium line altitude (ELA) reconstructions using remotely sensed imagery, high-resolution topographic data, and GIS mapping provide estimates of paleo-temperature associated with glacier advances. Results show that by 15.9 ka glaciers had retreated up-valley from their maximum LGM extent to a position that would remain ice covered until 6.2 ka. This retreat was interrupted by a glacier re-advance between 14 and 10.5 ka. Glaciers retreated after 10 ka, forming a series of recessional moraines but maintained positions down-valley of the location of the initial late-Pleistocene deglaciation. This glacial extent was maintained until after 6.2 ka when glaciers retreated further up valley and disappeared from some watersheds. Four small glacier advances occurred between 0.8 and 0.1 ka followed by rapid retreat and disappearance of ice from most watersheds.
DE: 1620 Climate dynamics (3309)
SC: Global Climate Change [GC]
MN: 2004 AGU Fall Meeting