Seismic Pre-Site Survey for ICDP Drilling Locations at Lake Nam Co, Tibet

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Through a cooperation between the Universities of Bremen and Jena and the Institute of Tibetan Plateau Research/Chinese Academy of Sciences, Beijing, a second seismoacoustic survey in 2016 extended the 2014 data set and is now well covering one of the largest lakes on the Tibetan Plateau.This proposal targets for the finalization of data processing and interpretation of the newly acquired data (2016) as well as to support the scheduled ICDP workshop in Beijing 2018 and the intended ICDP drilling proposal. The lake resembles a deep sediment fill of more than 500 meters, which may represent of climate archive for a million year timescale.Being in a transpressional and transtensional tectonic setting, the associated local subsidence, which follows a complex evolution in space and time, has promoted the development of significant accommodation space, which has even ensured deposition during lake level lowstands. The tectonics pattern itself is a target for a detailed reconstruction, as well as the response and evolution of the lake depositional system.An important topic for the third year is targeting the reconstruction of lake level changes, in particular for times of much elevated lake levels (mega lake hypothesis). Few documents with somewhat conflicting evidence indicate lake levels of at least 100 m higher than today, during marine isotope stage 5. Seismic data should reveal such situation by the presence of fine grained low reflective units, which shall be mapped and constrained by the stratigraphic models.