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    Climatic and glacial impact on erosion patterns and sediment provenance in the Himalayan rain shadow, Zanskar River, NW India

    Jonell, T.N. and Carter, Andrew and Boning, P. and Pahnke, K. and Clift, P.D. (2017) Climatic and glacial impact on erosion patterns and sediment provenance in the Himalayan rain shadow, Zanskar River, NW India. GSA Bulletin 129 (7-8), pp. 820-836. ISSN 0016-7606.

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    Abstract

    Erosion is a key step in the destruction and recycling of the continental crust yet its primary drivers continue to be debated. The relative balance between climatic and solid Earth forces in determining erosion patterns and rates, and in turn orogenic architecture, is unresolved. The monsoon-dominated frontal Himalaya is a classic example of how surface processes may drive focused denudation and potentially control structural evolution. We investigate whether there is a clear relationship between climate and erosion in the drier Himalayan rain shadow of northwest India where a coupled climate-erosion relationship is less clear. We present a new integrated dataset combining bulk petrography, geomorphometric analysis, detrital U-Pb zircon geochronology, and bulk Nd and Sr isotope geochemistry from modern river sediments that provides constraints on spatial patterns of sediment production and transport in the Zanskar River. Zanskar River sands are dominated by Greater Himalayan detritus sourced from the glaciated Stod River catchment that represents only 13% of the total basin area. Prevalent zircon peaks from the Cambro-Ordovician (440–500 Ma) and Mississippian-Permian (245–380 Ma) indicate more abundant pre-Himalayan granitoids in the northwest Himalaya than in the central and eastern Himalaya. Erosion from the widely-exposed Tethyan Himalaya, however, appears modest. Spatial patterns of erosion do not correlate with highest channel steepness. Our data demonstrate that Zanskar differs from the monsoon-soaked frontal Himalaya and the arid, extremely slow-eroding orogenic interior in that focused erosion and sediment production are driven by glaciers. Subsequent remobilization of glacially-derived sediments is likely controlled by monsoonal rainfall and we suggest sediment reworking plays an important role. These data support strong climatic control on modern orogenic erosion on the periphery of the Himalayan rain shadow.

    Metadata

    Item Type: Article
    School: School of Science > Earth and Planetary Sciences
    Research Centres and Institutes: Earth and Planetary Sciences, Institute of
    Depositing User: Andy Carter
    Date Deposited: 05 Jul 2017 11:05
    Last Modified: 27 Jun 2020 01:35
    URI: https://eprints.bbk.ac.uk/id/eprint/19136

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