EGU2020-384, updated on 12 Jun 2020
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Holocene megaflood history and provenance of the upper Indus-River. Implication for human migration along the ancient Silk Road at Ladakh.

Choudhurimayum Pankaj Sharma1, Poonam Chahal2, Anil Kumar1, Pradeep Srivastava1, Saurabh Singhal1, Rajesh Agnihotri3, Robert J Wasson4, Alan D Ziegler5, and Uma Kant Shukla6
Choudhurimayum Pankaj Sharma et al.
  • 1Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248001, India
  • 2Department of Geology, HNB Garhwal University, Srinagar 249161, India
  • 3Birbal Sahni Institute of Palaeosciences, Lucknow, India
  • 4School of Science and Engineering, James Cook University, Cairns, Queensland, Australia
  • 5Department of Geography, National University of Singapore, Singapore
  • 6Department of Geology, Banaras Hindu University, Varanasi, India

          The Indus River originating from the Manasarovar Lake runs along the Indus Tsangpo Suture Zone at Ladakh separating the Tethyan Himalaya in the south from the Karakoram Zone in the north. Due to the barrier created by the Pir Panjal Ranges and the Higher Himalaya, Ladakh falls in the rain shadow zone of ISM (Indian Summer Monsoon) with an average annual temperature of ~7.3°C. Random catastrophic hydrological events are known to endanger lives and properties of people residing here. So, determination of frequency, recurrence and forcing mechanism of past extreme floods are crucial in this highly vulnerable area.

          Here we studied Holocene mega flood history of the Upper Indus River at Ladakh using slack water deposits (SWDs). SWDs are composed of stacks of sand-silt couplets deposited during high flooding events. They are deposited instantly from suspension associated with sharp reduction of flow velocity due to local obstructions. Each couplet represent a flooding event. These events are dated employing Optically Stimulated Luminescence (OSL) using sand and AMS 14C using charcoal specks and hearth layers. The frequency of these events suggest higher occurrence of mega floods during pronounced northward penetration of ISM. Recurrence Interval (RI) analysis of these events suggest spatial variation in forcing mechanism between the trunk and the main tributary channel (Zanskar). Sedimentary provenance of these events are also analyzed using detrital zircon geochronology. The provenance analysis indicate more efficient sediment transportation along the Zanskar River as compared to the main Indus channel. Post LGM (Last Glacial Maximum) human migration along the channel is revealed from hearths found within these SWDs which generally occurs during post flooding episodes. Materials found within the hearths, chronology and the fashion of occurrence imply migration and cultural connectivity between the Indian sub-continent and the Central Asia along the ancient Silk Road at Ladakh as old as ~14 ka.

How to cite: Pankaj Sharma, C., Chahal, P., Kumar, A., Srivastava, P., Singhal, S., Agnihotri, R., Wasson, R. J., Ziegler, A. D., and Shukla, U. K.: Holocene megaflood history and provenance of the upper Indus-River. Implication for human migration along the ancient Silk Road at Ladakh., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-384,, 2019


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