Lacustrine sediments provide essential insights into decadal to millennial-scale climate variability and its driving mechanisms. Lake basins are natural sediment traps and thus geo-archives that continuously record environmental and climatic evolution. Our new analytical approaches allow for deciphering the timing and dynamics even of very rapid climate changes and extreme hydrometeorological events causing short-term catchment runoff at seasonal resolution. In this project we investigate sediment records of two lakes in the Eastern Cordillera (NW Argentina). This region is of particular interest for reconstructing past variations in moisture availability because of the very strong gradient in precipitation over short distances.
The main scientific goals and questions to be addressed include (1) testing previous ideas of wetter conditions during times of insolation maxima in January driven by variations in the Earth’s orbital parameters; (2) investigating centennial and decadal-scale oscillations in moisture availability and their causes; and (3) testing the hypothesis that changes in climatic boundary conditions can cause changing frequencies of extreme meteorological events. To achieve these goals, we have selected two adjacent lake sediment records from the Yala lake group located northwest of Jujuy based on their basin morphology and type of sediment infill. We have obtained 8 and 12 m long sediment profiles from the lakes Laguna Rodeo (2041 m asl) and Laguna Commodero (2026 m asl). Sediment analyses include micro-facies analyses on thin sections, high resolution (200 micron) XRF element scanning, organic and inorganic carbon determination, stable oxygen and carbon isotope analysis on carbonates, mineralogical analyses, and AMS-C14 dating.
Universidad Nacional de Jujuy (Argentina)
German Research Foundation (DFG)
Federal State of Brandenburg