71-5 Geomorphic Expression of extensional tectonics in the Higher Himalaya "A case study from Kishtwar Basin"

Session: The Geodynamic Evolution of the Himalaya: From Mountain Building to Modern Seismicity and Climate Change (Posters)

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Abstract:

The extensional tectonic basin is reported from the northwestern Higher Himalaya wherein Quaternary sediments are deposited in  narrow corridor between two faults that are less than 03 km apart. In this study integrated geomorphic, geophysical and geological investigation have been carried out to understand the nature of basin and mechanism involved in the origin. The landforms reported from this study include, fault scarps, rhombohedral basin, drainage offset, uplifted lacustrine sediments, and faulted river terraces. The ~10 km long and 2-3 km wide Quaternary Kishtwar basin, is bordered by normal faults, with en~echelon behaviour. The basin is flat-topped at the center and asymmetric at either ends with complex fault system. Based on the integrated approach we concluded that the basin resemble with the Death valley type pull apart basin which is although highly oblique to the transform direction. The basin developed above a small step over of Kishtwar Strike Slip fault oblique to the overall motion of Indian plate. The geophysical survey with the help of Ground Penetrating Radar suggest the sub-surface deformation of sediments. The dating of deformed sediments from the trench section suggest three palaeoseismic events within the time range of 16.35 ±2.13ka-13.14±0.91ka, 13.14±0.91-7.89±0.71ka and 7.89±0.71ka-5.44±0.54ka. The dating of deformed sediments across the fault scarps of master fault revealed a long term slip rate of 1.14 mm/year. The smaller cross faults may have distributed the horizontal and vertical slip along the master fault.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9732

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