The Climatic and Environmental History of the Amazon Basin Since the Last Glacial Maximum

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Abstract ATM-9528280 Colinvaux, Paul A. Smithsonian Institution Title: The Climatic and Environmental History of the Amazon Basin Since the Last Glacial Maximum This award will contribute to the reconstruction of the vegetation and climate history of the Amazon Basin at the last glacial maximum using. The project will focus on core-drilling and pollen analysis of the sediments of ancient Amazonian lakes. A climatic history of the Amazon (an area roughly as large as the continental U.S.) is necessary for calibrating global climate models. Changes in three climate parameters in ice-age time are likely: CO2, temperature, and precipitation. Research to date has developed ice-age temperature records at six sites in the tropical Americans. Pollen evidence shows changes in the range of temperature-sensitive plants suggesting cooling by 6oC. This cooling suggests also that tropical rainforest occupied the lowlands of the Amazon basin in glacial times, where the effects of cooling should have been least. Pollen from a drill core through the Amazon fan also suggests that dry vegetation was no more prevalent in the ice-age than it is today. The goal of the present project is to test these conclusions with cores from ancient lakes in the Amazon `asin. The prime method of paleoclimate and paleoecological reconstruction will be pollen analysis, calibrated by a program of surface pollen sampling. This work will allow reliable general conclusions both about the ice-age climate and the recent history of the world's most diverse forest.