HR: 1340h
AN: PP33B-0928    [Abstracts]
TI: Deglacial History of the Ecuadorian Andes and Implication for Climate Variations: Preliminary Results
AU: Hall, M
EM: volcan\_pete@yahoo.com
AF: Escuela Politecnica Nacional, Instituto Geofisico, Campus Ing. Jos‚ Rub‚n Orellana, Apartado 2759, Quito, _ Ecuador
AU: * Rinterknecht, V R
EM: vincent@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964 United States
AU: Schaefer, J M
EM: schaefer@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964 United States
AU: Seager, R
EM: seager@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 61 Route 9W, Palisades, NY 10964 United States
AU: Greene, A
EM: amg@ldeo.columbia.edu
AF: International Research Institute for Climate Prediction, 61 Route 9W, Palisades, NY 10964 United States
AB: Paleoclimate reconstructions are essential for evaluating the future evolution of natural climate variability and for determining climate sensitivity to external forcing. Reconstructing climate conditions from the Last Glacial Maximum (LGM) to the Holocene represents a unique opportunity to understand climate variability from full glacial conditions to modern warm conditions. The primary goal of our project, is to verify if the changes in temperature and precipitation driving the glacier event in the tropics during the well-documented Little Ice Age (LIA), may also account for the glaciations related to the LGM and the late glacial period. This inter-disciplinary project brings together specialists in glacial geology, surface exposure dating, and climate modeling. Our first trip to Ecuador took us to the Papallacta Valley at the rim of the Potrerillos Plateau. We developed detailed maps of the snowline lowering in the valley and took samples in well-exposed sections for radiocarbon dating. We used our maps and the age constraints on the deglacial history of the Papallacta Valley to estimate the possible combinations of changes in climate parameters related to reconstructed snowline variations. This local study represents the first step in a broader project that will cover most of the Ecuadorian Andes. We will also provide direct dating ($^{3}$He, $^{10}$Be, and $^{36}$Cl) of the moraine sequences deposited during the retreat of the glaciers during the late Pleistocene. By the time of the project completion we want to evaluate the nature of the driving forces underlying the LGM and the late glacial event in view of the relatively well understood mechanisms behind the termination of the LIA, and we want to compare the produced data to mid- and high- latitude areas in order to evaluate the regional footprint of dimension and timing of glacier response to climate change.
DE: 9360 South America
DE: 1035 Geochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting