Towards an ICDP drilling at Lake Nam Co (Tibet)
Torsten Haberzettl1, Gerhard Daut
1, Junbo Wang
2, Liping Zhu
3, Thomas Kasper
1, Roland Maeusbacher
1, Peter Frenzel
4, Klaus R Reicherter
5, Antje Schwalb
6, Volkhard Spiess
7 and Thomas Wilke
8, (1)Friedrich Schiller University of Jena, Physical Geography, Jena, Germany, (2)Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China, (3)University of Chinese Academy of Sciences, Beijing, China, (4)Friedrich Schiller University of Jena, Institute of Geosciences, Jena, Germany, (5)RWTH Aachen University, Aachen, Germany, (6)Technical University of Braunschweig, Braunschweig, Germany, (7)University of Bremen, Faculty of Geosciences, Bremen, Germany, (8)Justus-Leibig University Gießen, Department of Animal Ecology & Systematics, Gießen, Germany
Contact First Author: Torsten Haberzettl; torsten.haberzettl@uni-greifswald.de
English Abstract:
Nam Co is one of the largest and deepest lakes on the Tibetan Plateau (TP). Seismic data show an infill of >800 m of well layered undisturbed sediments in the central part of the lake. Sediment accumulation rates measured on a 10.4 m reference core, seismostratigraphic investigations, and molecular clock analyses suggest an age of the seismically imaged sequence between 460 and 1,900 ka. However, no basement reflector has been found indicating even older sequences. Multiproxy studies on the reference core provide an excellent high-resolution paleoclimate record covering the past 24 ka cal BP validated by extensive modern process studies and multi-dating approaches.
Situated on the central part of the TP, Nam Co is at an ideal location filling a gap in two ICDP/IODP transects. Due to this location at the intersection of Monsoon (increased precipitation) and Westerlies (increased evaporation) paleoclimate proxies clearly reflect the spatial and temporal interplay and thus the dominance of one of the two circulation systems. Considering that almost one third of the population of the world depends on the water supply from the TP the future hydrological development which is dependent on the interplay of the two systems will clearly have a major societal impact. To define parameters for future climate change scenarios and their consequences for ecosystems, it is of paramount importance to improve our knowledge of timing, duration, and intensity of past climatic variability and environmental impact, especially on long time scales.
Furthermore, the TP is characterized by a high degree of endemism of organisms that are dependent on continuously existing water bodies. Nam Co likely served as a dispersal centre for these organisms, as other shallower lakes desiccated during dry glacial periods of the Cenozoic. Nam Co appears to be a first class example for studying the link between geological and biological evolution in highly isolated TP ecosystems over long time scales.
