Quaternary glaciation of Puruogangri - the largest modern ice field in Tibet

The Puruogangri, the largest modern ice field in the Tibetan Plateau with an area of over 400 km(2) in total, is in the inner plateau. Although it is very difficult to reach, the scale of the ice field makes it important to study the Quaternary glaciation in this inland area to determine whether there was a unified ice sheet in the Tibetan Plateau during the Quaternary. Field observation showed that five moraine groups termed Moraine I-V of terminal moraines and lateral moraines are present, located from the snouts of modern glaciers to the piedmont. Based on geomorphic locations, stratigraphic correlation, relative weathering, reworked degrees by wind action and the ESR ages of the sands covering the gobi with erratics, as well as through comparison with the Quaternary glaciations with numerical ages in western Chinese mountains, these moraine groups represent the modern moraine, the Little Ice Age, Neoglacial, the late stage of the Last Glaciation and the early stage of the Last Glaciation, respectively. The granite boulders of Moraine V are scattered for similar to6 km from the mountain front on an extensive peneplain. This suggests that the ancient glaciers in the west slope of the ice field advanced to the Piedmont during the late Pleistocene, but did not integrate with the ice in the mountains nearby to form a unified ice sheet. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved.