Collaborative Research: RUI--Late Holocene Climate of the Central Andes Identified from Sedimentary, Stable Isotopic, Geochemical and Biological Proxies

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This project is designed to obtain high-resolution paleoclimate records from a series of lakes in the central Andes spanning latitudes 11 degrees south to 20 degrees south, and will document climatic variability at the highest possible temporal-resolution (5 to 20 years based on previous work) from lakes in this region. The resulting spatial-temporal dataset will provide information regarding drought frequency, intensity and spatial variability across a region where millions of people live at a subsistence level, limited water-resources, and rapidly retreating glaciers that currently supply an important source of water during the winter dry season.Sediment cores recovered from the center of deposition in of each lake will be used to document changes in the hydrologic status through time by measuring oxygen and carbon isotopic ratios on either ostracod shells or authigenic carbonate (where available), or sediment cellulose where the bedrock geology does not allow for the preservation of authigenic calcium carbonate in the sediments. These analyses will be augmented with core transect studies from shallow to deep water to identify and date large-scale variations in lake level. Results will be quantified using modeling studies of stable isotope mass balance and hydrologic status. The results arising from this work will be studied alongside other paleorecords from the Pacific Rim to identify the likely climatic mechanism(s) responsible for the observed changes. In particular, results will be compared with long records of the El Nino/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). This information is expected to be helpful for forecasting, preparing and planning for future droughts.