LEO PARGIL (India)

ABSTRACT:

The Himalaya provide an exceptional opportunity to investigate the evolution of mid-crustal rocks in an active collisional system. Along the collisional front, the major structures that bound these mid-crustal rocks, the Main Central thrust below and South Tibetan detachment above, are offset or reactivated by young metamorphic domes like the Leo Pargil and Lhagoi Kangri, the focus of this study. Such domes provide an important opportunity to study the generation of partial melt, the potential feedback between partial melt and exhumation, the affects of shear zone nucleation, and the rheology of the crust during dome for
mation. The high-grade rocks of the Leo Pargil dome have been exhumed during extension and dome formation within an active convergent setting along orogen-parallel thrust faults and low angle detachment faults that were active until the middle Miocene. In collaboration with US and international academic organizations this project will employ a field-and lab-based interdisciplinary investigation to explore the evolution of these rocks using 1) geologic mapping and detailed microstructural analysis, 2) isotope geochronology (U/Pb), and 3) determination of metamorphic P-T-t paths. Results from Leo Pargil will be contrasted with that from other domes along the Himalayan front to generate a high-resolution model for the timing and kinematics of orogen-parallel mid-crustal flow and exhumation along the southern margin of the Tibetan plateau since the middle Miocene.


Collaborators

  1. J. Cottle - University of California, Santa Barbara

  2. T. Ahmad - University of Jamia Millia Islamia, India


Grants

NSF-EAR-0911561: Collaborative Research: Orogen-parallel mid-crustal flow and exhumation of domes along the southern margin of the Tibetan plateau. M. Jessup and J. Cottle. National Science Foundation Tectonics Program. 10/01/09-09/30/12.


Students

  1. White White (MS) 2013

  2. Jackie Langille (PhD) 2012

  3. Graham Lederer (PhD UCSB)

  4. Richard Powlus (BS) 2012

  5. Douglas Conner (BS) 2011

  6. Nicholas Costello (BS) 2010


PUBLICATIONS

Jessup, M.J., Langille, J., Cottle, J.M. & Ahmad, T. (2016) Crustal thickening, Barrovian metamorphism, and exhumation of mid-crustal rocks during doming and extrusion: Insights from the Himalaya, NW India. Tectonics, 35, doi:10.1002/2015TC003962.

*Langille, J., Jessup, M.J., Cottle, J.M., Lederer G., & Ahmad, T. (2012) Timing of metamorphism, melting, and exhumation of the Leo Pargil dome, NW India. Journal of Metamorphic Geology. DOI: 10.1111/j.1525-1314.2012.00998.x

*Langille, J., Jessup, M.J., Cottle, J.M. & Ahmad, T. (2014) Kinematic and thermal studies of the Leo Pargil Dome: Implications for the tectonic evolution of extension in the northwest Indian Himalaya. Tectonics, 33, 1766-1786. 10.1002/2014TC003593.

*Lederer, G., Cottle, J., Jessup, M., Langille, J., & Ahmad, T., (2013) Time-scales of partial melting in the Himalayan middle crust: insight from the Leo Pargil dome, northwest India, Contributions to Mineralogy and Petrology, 166 (5), 1415-1441. Lederer_et_al_2013.pdf


 

STAIN PARTITIONING, PARTIAL MELTING & exhumation of domes along the southern margin of the Tibetan Plateau