Late pleistocene, Late-glacial and Holocene glacier advances on the Tibetan Plateau

Abstract

Abstract Many end-moraine sequences in various mountain areas of the Tibetan Plateau have already been investigated in detail, but a homogeneous chronostratigraphy is still lacking. The ice-marginal limits are commonly given local names and often the classification does not seem to be secure. This is one reason for controversial discussions on the ice extent at the LGM. Because most organic material in Tibet developed at the beginning of the Holocene, only a few older radiocarbon dates are available. Up to now, Late-glacial terminal moraines have been found in the western Kunlun Shan and in the Tian Shan. Their radiocarbon ages (ca. 15 ka BP) correspond to a glacier advance south of the Qaidam basin, which can be correlated with Late-glacial lacustrine sediments. In Eastern Tibet different ages of peat development in different tongue-like basins have been obtained. Even the bases of peat bogs in basins at Nianbaoyeze mountains enclosed by (apparent) LGM end moraines gave Holocene ages. Three main Holocene intervals have been radiocarbon dated from palaeosols and basal peat layers in the area. Except for a younger glacier re-advance at about 3000 BP, and those of the Little Ice Age, the age of many last glaciation glacier advances on the Tibetan Plateau are constrained only on the basis of organic matter lying on top of the moraines and therefore might be of Late-glacial or Pleistocene age.