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    Slowing rates of regional exhumation in the western Himalaya: fission track evidence from the Indus Fan

    Zhou, P. and Carter, Andy and Li, Y. and Clift, P.D. (2019) Slowing rates of regional exhumation in the western Himalaya: fission track evidence from the Indus Fan. Geological Magazine , ISSN 0016-7568. (In Press)

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    Abstract

    Weuse apatite fission track ages from sediments recovered by the International Ocean Discovery Program in the Laxmi Basin, Arabian Sea, to constrain exhumation rates in the western Himalaya and Karakoram since 15.5 Ma. With the exception of a Triassic population in the youngest 0.93 Ma samples supplied from western Peninsular India, apatite fission track ages are overwhelmingly Cenozoic, largely <25 Ma, consistent with both a Himalaya–Karakoram source and rapid erosion. Comparison of the minimum cooling age of each sample with depositional age (lag time) indicates an acceleration in exhumation between 7.8 and 7.0 Ma, with lag times shortening from ∼6.0 Myr at 8.5–7.8 Ma to being within error of zero between 7.0 and 5.7 Ma. Sediment supply at 7.0–5.7 Mawas largely from the Karakoram, and to a lesser extent the Himalaya, based on U–Pb zircon ages from the same samples. This time coincides with a period of drying in the Himalayan foreland caused by weaker summermonsoons andWesterly winds. It also correlates with a shift of erosion away from the Karakoram, Kohistan and the Tethyan Himalaya towards more erosion of the Lesser and Greater Himalaya and Nanga Parbat, as shown by zircon U–Pb provenance data, and especially after 5.7 Ma based on Nd isotope data. Samples younger than 5.7 Ma have lag times of ∼4.5 Myr, similar to Holocene Indus delta sediments.

    Metadata

    Item Type: Article
    Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication following peer review. The version of record is available online at the link above.
    Keyword(s) / Subject(s): International Ocean Discovery Program, fission track, erosion, Himalaya, Indus Fan, monsoon
    School: Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences
    Research Centre: Earth and Planetary Sciences, Institute of
    Depositing User: Andy Carter
    Date Deposited: 17 Oct 2019 06:44
    Last Modified: 19 Oct 2019 00:05
    URI: http://eprints.bbk.ac.uk/id/eprint/29396

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