The relationship between climate change and Quaternary glacial cycles on the Qinghai-Tibetan Plateau: review and speculation

The Quaternary climatic history of the Qinghai-Tibetan Plateau is reconstructed using Quaternary glacial geologic data. Four major glaciations are recognized: the Xixiabangma, Naynayxungla, Guxiang (the Penultimate), and Baiyu (the Last) Glaciation. These are dated at about 800-1170, 500-720, 130-300, and 10-70ka, respectively. These correspond to marine oxygen isotopic stages (MIS) 20 similar to 36, 14 similar to 18, 6 similar to 8, and 2 similar to 4. The most extensive glaciation occurred during the Naynayxungla Glaciation when there were many large ice caps, glacier complexes and great valley glaciers, covering a total area greater than or equal to500,000 km(2). The Guxiang Glaciation (Stage 6) was characterized by valley glaciers, while during the Baiyu Glaciation (Stages 2-4) the glaciers were more restricted in extent and covered a total area of similar to350,000 km(2). These data show that glaciation become less extensive throughout the Quaternary and may have been the result of variations in climate in response to changing patterns of insolation related to changes in the Earth's orbit. (C) 2002 Elsevier Science Ltd and INQUA. All rights reserved.