IMPACTS OF TECTONIC CHANGES ON THE REORGANIZATION OF THE CENOZOIC PALEOCLIMATIC PATTERNS IN CHINA

Abstract

Geologic studies have illustrated that the planetary-wind-dominant climate in the Paleogene is changed into the monsoon-dominant one near the Oligocene/Miocene boundary in China. The evolution is marked by the changes of regional aridity/humidity contrasts. The contrasts occur between the south and the north part of China in the Eocene, and then between East China and Central Asia near the Oligocene/Miocene boundary, indicating the onset of monsoon-dominant climate in China. The impacts of the Himalaya-Tibetan plateau uplift and/or the Paratethys Sea retreat on the Asian monsoon have been well demonstrated. However, whether or not other factors have affected the above reorganization of paleoclimatic patterns remains a question to be addressed. Additional factors that should be addressed at least include the Indian Peninsular drift, the South China Sea expansion and the East China Sea transgression. Here we use the IAP-AGCM to explore their roles in the above paleoclimatic evolution. Our experiments demonstrate that the South China Sea expansion is another major forcing, in addition to the important roles of the Paratethys retreat and the Himalaya-Tibetan plateau uplift. On the contrary the impacts of the Indian Peninsular drift and the East China Sea transgression are relatively subordinate. The Himalaya-Tibetan plateau uplift plays a crucial role in the magnification of the aridity/humidity contrasts between the south and the north part of China. The Paratethys retreat, the Himalaya-Tibetan plateau uplift and the South China Sea expansion coact to cause the formation of the aridity/humidity contrasts between East China and Central Asia. The retreat and the uplift favor the dynamic condition, and the expansion provides the water vapor condition for the monsoon-dominant climate in China. © 2007 Elsevier B.V. All rights reserved.