Tuesday, June 11, 2013

Exhumation Patterns Of Dhauladhar Range Himalayas: Interplay Of Tectonics And Climate

Open access in Current Science:

 New apatite and zircon fission-track ages from the Dalhousie Granite exposed along Dhauladhar Range, Northwest Himalaya extend from 2.9 ±  0.2 to 4.4± 1.0 Ma and 10.4 ±  1.4 to 21.1 ±  2.2 Ma respectively. One-dimensional thermal modelling of the data suggests slow exhumation during Middle to Late Miocene, followed by acceleration during Plio-Pleistocene. The activity along the Panjal Thrust (PT)/Main Central Thrust (MCT) in this region ceased at ~ 15 Ma, while tectonic activity along the Main Boundary Thrust (MBT) started prior to ~ 10 Ma. Tilting of topography due to activation of MBT controls the exhumation pattern of Dalhousie Granite during Middle to Late Miocene. Correlation among structure, topographic pattern and thermochronometric ages indicates interplay between tectonics and erosion controlled  exhumation along the mountain front. The fast exhumation rates since Pliocene are synchronous with intensification of the Asian monsoon and suggest a causal link between erosion and climate variation for evolution of the landscape.

What is heartening to see is that research like this requiring sophisticated geochemical analysis is coming out of regional Universities like Kurukshetra and Ambala.  Ten to fifteen years ago, a paper like this would be most likely published from labs of just a few elite institutions in India, with the analysis being done by a Western collaborator in a U.S. or European University. That is still the case with many research programs, where Indian geologists seek collaboration to access instrumentation not easily available in India, but with more money being available through Science and Technology Ministry grants, the research environment may be slowly changing.

A while ago I had an email exchange with a senior geology faculty where I ventured to ask him if my perception was correct that many really large research projects on Himalayan tectonics involve primarily Western researchers with a solitary India based colleague. He agreed somewhat, but opined that this was not because there is a lack of research funding potentially available to address Himalayan geology, but rather funding towards subjects like climate change, groundwater, Quaternary processes and environmental geology has increased and many researchers today prefer more theoretical and lab based work than difficult high altitude Himalayan fieldwork!

A bit unkind I thought :).. but this paper is a departure from such slack attitudes if they really do exist!

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