Holocene Paleohydrology of the Subtropical Andes from Lake Records

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Abstract ATM-9613991 Seltzer, Geoffrey O. Syracuse University Title: Holocene Paleohydrology of the Subtropical Andes from Lake Records The primary objective of this project is to establish new multi- proxy Holocene paleoclimate records from the subtropical Andes. Previous work suggests a prolonged period of aridity during the mid-Holocene, however, more work to produce diatom and isotope records is necessary to confirm this hypothesis and determine the extent of this dry phase. Specifically, this award will support a study to define the timing of changes in the precipitation- evaporation balance of the Andean Altiplano on a decadal to century timescale for the Holocene. These records are needed to understand the long-term atmospheric dynamics of the subtropics and to assess the importance of decadal to millennial-scale shifts in the strength of summer convection. The Holocene climate history of the region will be reconstructed by analyzing the sediment, geochemical, magnetic, isotopic, and diatom content of lake cores dated at high-resolution by 210Pb and AMS 14C measurements. A transect of sites ranging from approximately 15o to 20oS in the eastern cordillera of Bolivia will be investigated. Such a record of changing effective moisture will provide insight into the long- term climate variability of subtropical South America. Changes in water resources may have also significantly impacted prehistoric people living on the Altiplano and may again be an important environmental factor for future populations in the region.