Skip to main content

Does the Middle Miocene rise of the Greater Himalaya cause the slow down of Southern Tibet exhumation?

The Himalaya is the highest and steepest mountain range on Earth and forms today efficient north-south barrier for moisture-bearing winds. 1D-thermokinematic modeling of new zircon (U-Th)/He bedrock-cooling ages and >100 previously published mica 40Ar/39Ar, zircon and apatite fission track ages from the Sutlej Valley document a consistent rapid decrease in exhumation rates that initiated at ~17-15 Ma across the entire Greater and Tethyan Himalaya and the north-Himalayan Leo Pargil dome. We observe a rapid decrease from >1 km/Myr to <0.5 km/Myr. We explain the middle Miocene deceleration of exhumation with major tectonic reorganization of the Himalayan orogen, probably coincident with the onset of basal accretion, which resulted in accelerated uplift of the Greater and Tethyan Himalaya. The period of slow exhumation in the upper Sutlej Valley coincides with a period of internal drainage in the south-Tibetan Zada Basin farther upstream, which we interpret to be a consequence of tectonic damming. Comparison with other data from the Himalaya and Southern Tibet along strike suggests that by ~15 Ma, southern Tibet was high, located in the rain shadow of the High Himalaya and eroding slowly for at least 10 Ma, before erosion accelerated again by ~5-3 Ma, most likely due to climatic changes. Our new finding document that the location of tectonic deformation processes controls the first order spatial pattern of both climatic zones and erosion across the orogen. Therefore, we think that the rise of Greater Himalaya is linked to the deceleration of exhumation in Southern Tibet.

Details

Author
Rasmus C. Thiede1, Dirk Scherler2, Chistoph Glotzbach3
Institutionen
1Institut für Geowissenschaften, Christian Albrecht Universität zu Kiel, Germany; 2Institut für Geographische Wissenschaften, Freie Universität Berlin, Germany;Helmholtz Zentrum Potsdam, Deutsches GeoForschungs Zentrum GFZ, Germany; 3Institut für Geowissenschaften, Universität Tübingen, Germany
Veranstaltung
GeoBerlin 2023
Datum
2023
DOI
10.48380/k7v1-sv65
Geolocation
India - Asia collision