Quaternary Paleoclimatic Record from Tropical South America: Lake Titicaca

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Abstract ATM-9616972 Baker, Paul A. Duke University ATM-9708257 Dunbar, Robert B. William Marsh Rice University ATM-9708256 Fritz, Sherilyn C. LeHigh University ATM-9708258 Seltzer, Geoffrey Syracuse University Title: Quaternary Paleoclimate Record from South America: Lake Titicaca A long and continuous paleoclimate record from tropical South America is needed to answer several persistent and important questions. This award supports the recovery of such a record by coring the deep basin of Lake Titicaca on the northern Altiplano of Peru and Bolivia. Through the preliminary analysis of a series of short, mini-piston cores, it is demonstrated that the sediments of the lake are suitable for climatic reconstruction. Previous studies revealed large-amplitude fluctuations of lake level in the Holocene and Pleistocene, implying that effective moisture (and probably temperature) has dramatically fluctuated. Siting of a series of long cores will be aided by medium-resolution, deeper penetration seismic reflection profiling. The cores will be subsequently analyzed for chronology (AMS radiocarbon), sedimentology, physical properties, geochemistry, stable isotopic analysis of organic carbon and cellulose; determination of organic and inorganic phosphorous, and biogenic silica; and paleobiota (ostracode and diatom species compositions), This record will allow us to examine in detail the timing and mechanisms of tropical forcing of high-latitude climate, as well as the linkage between the climate of the Altiplano and the Amazon basin.