Reconstructing spatial & temporal patterns of past glaciation of the Tibetan Plateau, Tian Shan, & Altai Mountains using geomorphic mapping & cosmogenic radionuclide dating

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• Prof. Jon Harbor, Purdue University, Indiana, USA
• Thursday 20 February 2014, 16:30-18:00
• Small Lecture Theatre, Department of Geography, Downing Site.

If you have a question about this talk, please contact Dr Harriet Allen.

All welcome

Understanding the behaviour of mountain glaciers and ice caps, the evolution of mountain landscapes, and testing global climate models all require well-constrained information on past spatial and temporal patterns of glacier change. Particularly important are transitional regions that have high spatial and temporal variation in glacier activity and that can provide a sensitive record of past climate change. Central Asia is an extreme continental location with glaciers that have responded sensitively to variations in major regional climate systems. As an international team project, scientists from Europe, Asia and North America are reconstructing glacial histories of several areas of the Tibetan Plateau as well as along the Tian Shan, Altai and Kunlun Mountains. Building on previous work, we are using remote-sensing-based geomorphological mapping augmented with field observations to map out glacial landforms and the maximum distributions of erratics. We then use cosmogenic nuclide 10Be and 26Al dating, optically stimulated luminescence, and electron spin resonance dating of moraines and other landforms to compare dating techniques and to constrain the ages of former maximum extents of glaciers and ice caps. Comparing consistently dated glacial histories across central Asia will allow us to examine potential shifts in the dominance patterns of climate systems over time in the region. Results to date show significant variations in the timing and extent of glaciation, including areas in the southeast Tibetan Plateau and Tian Shan with extensive valley and small polythermal ice cap glaciation during the global last glacial maximum in contrast to areas in the central Tibetan plateau that had very limited valley glacier expansion during the global last glacial maximum. Initial numerical modelling fit to mapped and dated paleoglacial extents suggests that limited cooling is sufficient to produce observed past expansions of glaciers across the Tibetan Plateau.

This talk is part of the Climate and Environmental Dynamics - Department of Geography series.

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• Small Lecture Theatre, Department of Geography, Downing Site

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