Lake system response of Nam Co area, central Tibet, to Late Quaternary Monsoon dynamics: Microfossils as recorders of environmental change

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In August/September 2005, during the pilot phase of this project, we have carried out a limnological survey that included the collection of water column samples from Nam Co, water samples from tributaries, surface sediments and short cores. Long cores (max. 4.7 m) and outcrop sediments were collected in cooperation with partners. Preliminary analyses show that there are abundant microfossils, especially ostracodes that document the suitability of Nam Co sediments for an evaluation of the response of Nam Co and its catchment area to environmental dynamics and climate change. This proposal seeks funding for a detailed microfossil analysis of sediment cores and outcrop sediments in order to characterize the lake system response to climate change during (1) recent decades, and (2) during the Holocene, as well as to characterize the (3) dynamics of past lake level high stands. Fossil ostracode species assemblages and the oxygen and carbon isotopic signatures from their valves will provide information about, for example, the precipitation vs. evaporation ratio, lake level changes and water supply to the lake such as meltwater runoff that is controlled by monsoon dynamics and temperature. We also plan to carry out a second field work phase at Nam Co followed by an exploratory survey in S. Tibet together with cooperation partners.