Title: The growth of the Himalaya and Tibet and the evolution of Asian climate
Speaker: Professor Peter Molnar, Distinguished Professor, Department of Geological Sciences, University of Colorado, Boulder, USA
Abstract: The Indian subcontinent collided with southern Tibet approximately 50 million years ago, and its steady 2000-3000 km penetration into the rest of Asia built the Himalaya and the Tibetan Plateau. Approximately, 10 to 15 million years ago, despite the continued northward penetration of India into the rest of Asia, the Tibetan Plateau began to collapse with its average elevation dropping from approximately 6000 meters to its present day 4500-5000-meter average height. Surrounding regions, including the Shillong Plateau in India, the Tien Shan north of Tibet, even high terrain Mongolia emerged and grew into major mountain ranges. The emergence and redistribution of high terrain affected climate in different places in different ways. If the Indian monsoon changed, however, changes over most of India were slight, but rainfall over northwest India and Pakistan decreased. Concurrently, dust accumulation in northeast China increased, apparently because of the growth of the Mongolian Altay and Gobi Altay in Mongolia. I will argue that, and explain how, all of these changes, both in topography and in climate, are tied to the removal of cold dense mantle beneath Tibet, and its replacement by hotter, less dense material.
About the Speaker: Prof. Peter Molnar is very distinguished and eminent scholar / researcher who has tremendously contributed to the plate tectonics, mountain building processes and tectonic-climate interactions on regional as well as global scale. He has eminently integrated the geodynamic processes with seismic hazards, global and regional climate and made several fundamental contributions. One of the pioneering works was the closing of the Indonesian Seaway that may have transformed global climate to one with recurring ice ages ~3 million years ago. He made an immense impact on the application of earth surface processes to seismic hazard, ocean circulation and global / regional climate and significantly brought to fore the societal relevance of the earth science research.