Quaternary paleoenvironmental change on the Tibetan Plateau and adjacent areas (Western China and Western Mongolia)

This paper summarises the nature of climatic change during the Last Glacial -Interglacial cycle on the Tibetan Plateau and adjacent areas. The results are derived from inland glacier fluctuations, lake level changes and dust ( loess) records of Central Asia including Tibet. These are based on our fiel d investigations from 1988 to 1998 and literature surveys. The changing ext ents of different climatic controlled geomorphic landscapes and vegetation zones help to provide estimates of the magnitude of climatic change. Featur es, such as ice wedge casts, loess, and palaeosols, ELA-reconstruction's an d palaeobotanical data are used to help reconstruct palaeoprecipitation and palaeotemperatures. Weathering characteristics, the overlying strata and s ome luminescence dates indicate that there are two main glacial ice advance s during the last glacial cycle. These correspond to marine Oxygen Isotope Stages (OIS) 2 and 4. In some areas, as the eastern or northern margin of t he Tibetan Plateau, remnants of older glaciations are preserved. Higher lak e levels in the deserts of Central Asia and on the Tibetan Plateau are date d to > 40 to 25 ka (OIS 3) and to Late Glacial / Early to Mid Holocene peri ods. Our work supports the view that in many areas of Central Asia cold pha ses during the last glacial correspond with the maximum extent of glaciers and the periglacial activity. The last glaciation produced large alluvial f ans alternating with periods of high lake stands on the Tibetan Plateau. Ho wever, at the northern margin of the Plateau in the Qaidam Basin and in som e particular desert areas in Western China, high lake levels occurred also during the Pleistocene and are related with alluvial fans. (C) 2000 Elsevie r Science Ltd and INQUA. All rights reserved.