EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Middle Miocene rise of the Greater Himalaya establishing a new orographic barrier

Rasmus Thiede1, Dirk Scherler2,3, and Christoph Glotzbach4
Rasmus Thiede et al.
  • 1Christian Albrecht Universität zu Kiel, Institut für Geowissenschaften, Kiel, Germany (
  • 2Helmholtz Zentrum Potsdam, Deutsches GeoForschungs Zentrum GFZ, Germany
  • 3Institut für Geologische Wissenschaften, Freie Universität Berlin, Germany
  • 4nstitut für Geowissenschaften, Universität Tübingen, Germany

The Himalaya is the highest and steepest mountain range on Earth and an efficient north-south barrier for moisture-bearing winds. The close coupling of changes in topography, erosion rates, and uplift has previously been interpreted as an expression of a climatic control on tectonic deformation. Here, we present 17 new zircon U/Th-He (ZHe) bedrock-cooling ages from the Sutlej Valley that – together with >100 previously published mica 40Ar/39Ar, zircon and apatite fission track ages – allow us to constrain the crustal cooling and exhumation history over the last ~20 Myr. Using 1D-thermal modeling, we observe a rapid decrease in exhumation rates from >1 km/Myr to <0.5 km/Myr that initiated at ~17-15 Ma across the entire Greater and Tethyan Himalaya, as far north as the north-Himalayan Leo Pargil gneiss dome. This decrease is recognized both in the hanging and footwall of major Miocene shear zones and suggests that cooling is associated to surface erosion rather than to tectonic unroofing. We explain the middle Miocene deceleration of exhumation with major reorganization of Himalayan deformation and the onset of the growth of the Lesser Himalayan duplex. This resulted in accelerated uplift of the Greater Himalaya above a mid-crustal ramp, and thus forming a new efficient orographic barrier. The period of slow exhumation in the upper Sutlej Valley coincides with a period of internal drainage in the south-Tibetan Zada Basin further upstream, which we interpret to be a consequence of tectonic damming of the upper Sutlej River. External drainage of the Zada Basin was re-established ~1 Ma, when we observe exhumation rates in the upper Sutlej Valley to accelerate again. Our new finding document that the location of tectonic deformation processes control the first order spatial pattern of both climatic zones and erosion across the orogen.

How to cite: Thiede, R., Scherler, D., and Glotzbach, C.: Middle Miocene rise of the Greater Himalaya establishing a new orographic barrier, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4934,, 2021.

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