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Timing and mechanisms of Central Himalayan exhumation: discriminating between tectonic and erosion processes |
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| Authors: | Ana-Voica Bojar Harald Fritz Stefan Nicolescu Martin Bregar Ravi P Gupta |
| Institution: | Institute of Earth Science, Karl-Franzens University, Heinrichstrasse 26, A-8010 Graz, Austria;;Department of Geology and Geophysics, Yale University, PO Box 208109, New Haven, CT 06520–8109, USA;;Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee 247667, India |
| Abstract: | The ability to deduce exhumation mechanisms from thermochronological data is hampered by the fact that assumptions on the thermal state of the lithosphere have to be made. Additional argumentation is generally required to discriminate between erosion-controlled and tectonically induced exhumation. This problem can be overcome by studying the spatial distribution of zircon and apatite (U-Th)/He and fission track data. In this work the variation of four different low temperature isotopic systems generating age trends along a sampling line is used to infer mechanisms of Quaternary exhumation in the Central High Himalayan Metamorphic Belt. Observed zircon age trends with southwards increasing cooling ages (from 0.5 to 1.7 Ma) are attributed to tectonically induced exhumation. The uniform apatite cooling ages clustered c. 0.5 Ma are attributed to erosion. |
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