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Reconstructing the exhumation history of the Lesser Himalaya, Northern, India, from a multi-technique provenance study of the foreland basin Siwalik Group.

Najman, Yani and Bickle, Mike and Garzanti, Eduardo and Pringle, Malcolm and Barford, Dan and Brozovic, Nick and Burbank, Doug and Andò, Sergio (2009) Reconstructing the exhumation history of the Lesser Himalaya, Northern, India, from a multi-technique provenance study of the foreland basin Siwalik Group. Tectonics, 28 (TC5018).

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    Abstract

    This research presents the first multitechnique provenance study of the Siwalik Group in the Himalayan foreland basin in India, using the Jawalamukhi section, magnetostratigraphically dated at 13–5 Ma. Combined with provenance data from a Dharamsala Formation sedimentary section (21–13 Ma) located close by, it forms the longest temporally continuous record of Himalayan erosion in the Indian foreland basin. Sandstone petrography and heavy mineral analysis, conglomerate clast composition, Ar‐Ar dating of detrital white micas, and Sm‐Nd analyses on siltstones, conglomerate matrix and conglomerate clasts was undertaken to determine (1) shifts in source region through time and (2) changes in detrital lag times related to exhumation rates in the hinterland, together interpreted in the light of thrusting events. We interpret the data to show a slow down in exhumation rate of the Higher Himalaya by 16–17 Ma, after which time the locus of thrusting propagated south of the Main Central Thrust, and erosion of the low grade Haimanta Formation to the south became significant. The nonmetamorphosed Inner Lesser Himalaya breached its Haimanta cover by 9 Ma with the metamorphosed Inner Lesser Himalaya (Lesser Himalayan Crystalline Series) exhuming to surface by 6 Ma. This event caused sufficient disruption to established drainage patterns that all Higher Himalayan material was diverted from this location at this time.

    Item Type: Article
    Journal or Publication Title: Tectonics
    Additional Information: Copyright 2009 American Geophysical Union.
    Subjects: Q Science > QE Geology
    Departments: Faculty of Science and Technology > Lancaster Environment Centre
    ID Code: 39873
    Deposited By: Dr Yani Najman
    Deposited On: 03 Mar 2011 11:26
    Refereed?: Yes
    Published?: Published
    Last Modified: 26 Jul 2012 18:01
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/39873

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