Late Pleistocene Lake Level Fluctuations of the Nam Co, Tibetan Plateau, China
Schütt, Brigitta; Berking, Jonas; Frechen, Manfred; Yi, Chaolu
published: Sep 1, 2008
ArtNo. ESP023105202004, Price: 29.00 €
The endorheic Nam Co Lake, southeastern Tibetan Plateau, was selected to investigate the interrelation between post-glacial glacier decay and lake level fluctuations. During the transition between MIS 2 and MIS1glacier decay caused regional changes in water balance and a rise in lake level, which is presently shown by a marked cliff line visible all around Nam Co, with its base approx. 29 m above the present lake level. Simultaneously occurring melt water floods caused channel incision into the Pleistocene fan deposits; presently new fans are being deposited where the channels discharge into the wave-cut platform. More Holocene beach ridges on the wave-cut platform downslope of the cliff line are evidence of oscillating Holocene lake levels. LGM ice cap estimates for the tributary Nyainqentanghla Range explain about 50 % of the post-glacial lake volume growth compared to the present lake level. The remaining 50 % of post-glacial lake volume growth originates from increased inflow from the western and northern tributaries. As Nam Co is an endorheic lake, post-glacial water loss is primarily due to evaporation and moisture conditions. To understand late glacial interaction between glacier retreat and lake level fluctuation, a test site in the southeast of the Nam Co area was selected; investigations included geomorphological mapping, survey by DGPS and statistical data analysis.