Description

North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in

North-south-directed extension on the South Tibetan Fault System (STFS) played an important role in Himalayan tectonics of the Miocene Period, and it is generally assumed that orogen-perpendicular extension ceased in this orogenic system before the Pliocene. However, previous work in the Annapurna and Dhaulagiri Himalaya of central Nepal revealed evidence for local Pleistocene reactivation of the basal STFS structure in this area (the Annapurna Detachment). New structural mapping and (U-Th)/He apatite and zircon thermochronology in this region further document the significance of Pleistocene N-S extension in this sector of the Himalaya. Patterns of (U-Th)/He accessory-mineral ages are not disrupted across the reactivated segment of the STFS basal detachment, indicating that Pleistocene offset was limited. In contrast, the trace of a N-dipping, low-angle detachment in the hanging wall of the reactivated Annapurna Detachment - formerly linked to the STFS, but here named the Dhaulagiri Detachment - coincides with an abrupt break in the cooling-age pattern in two different drainages ∼20 km apart, juxtaposing Miocene hanging-wall dates against Pleistocene footwall dates. Our observations, combined with previous fission-track data from the region, provide direct evidence for significant N-S extension in the central Himalaya as recently as the Pleistocene.

Downloads
PDF (1.4 MB)

Details

Title
  • Evidence for Pleistocene Low-Angle Normal Faulting in the Annapurna-Dhaulagiri Region, Nepal
Contributors
Date Created
2015-03-01
Resource Type
  • Text
  • Collections this item is in
    Identifier
    • Digital object identifier: 10.1086/681219
    • Identifier Type
      International standard serial number
      Identifier Value
      0022-1376
    • Identifier Type
      International standard serial number
      Identifier Value
      1537-5269
    Note
    • Copyright 2015 by the University of Chicago Press. View the article as published at http://dx.doi.org/10.1086/681219

    Citation and reuse

    Cite this item

    This is a suggested citation. Consult the appropriate style guide for specific citation guidelines.

    McDermott, Jeni A., Hodges, Kip V., Whipple, Kelin X., Van Soest, Matthijs C., & Hurtado, Jose M., Jr. (2015). Evidence for Pleistocene Low-Angle Normal Faulting in the Annapurna-Dhaulagiri Region, Nepal. JOURNAL OF GEOLOGY, 123(2), 133-151. http://dx.doi.org/10.1086/681219

    Machine-readable links