Timing and extent of Quaternary glaciation in the Himalayan-Tibetan orogen
Abstract
Over the past few decades, satellite remote sensing, geomorphic mapping, analytical methods such as terrestrial cosmogenic nuclide and optically stimulate luminescence dating, and glacier-climate modeling has increased our understanding of the the extent and timing of Quaternary glaciation throughout the Himalayan-Tibetan orogen. Much focus has been placed on the desire to determine the forcing factors for glaciation, in particular the relative roles of the Asian summer monsoon and mid-latitude westerlies. There is much evidence for significant glacier advances over the past several glacial cycles with at least nine major regionally synchronous glacier advances are evident throughout the semi-arid and monsoon influenced regions. Evidence fort the oldest glaciations is restricted to the more arid interior of the orogen. The resolution of each of these glacier advances decreases with age, with the higher resolution of the Holocene glacial geologic record allows five regional glacier advances to be resolved. Despite broad synchronuity, glaciation varies in the timing and extent over relatively short distances (10-100 km), e.g., the local last glacial maximum occurred at different times with vastly different glacier extents. Moreover, the style of glaciation has changed significantly over the last several glacial cycles within semi-arid interior regions, from expanded ice caps to entrenched valley glaciation. Past and new studies show that the timing and extent of glaciation and the preservation of glacial evidence is likely governed by a complex combination of different factors specific to each locality. This include climate and microclimate regimes, tectonic setting, topographic controls and geologic setting. These studies are important in providing a natural benchmark for understanding present and future glacier and associated changes in the Third Pole Environment.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMGC41B..03O
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGE;
- 1621 Cryospheric change;
- GLOBAL CHANGE;
- 1631 Land/atmosphere interactions;
- GLOBAL CHANGE;
- 1655 Water cycles;
- GLOBAL CHANGE