Applying geodesy and modeling to test the role of climate controlled erosion in shaping Himalayan morphology and evolution
Department or Administrative Unit
The Himalaya-Tibet system is the archetype of continent-continent collision, but the role of climate in modulating orogenesis is a relatively new paradigm that has not been well tested with field-based deformation measurements. Phenomenal monsoon precipitation (>3 m/year) falls along the Himalayan front, and the resulting erosion is thought by some to promote out -of-sequence thrusting or even channel flow within the High Himalaya, leading to the observed, profoundly steep morphology. Others attribute High Himalayan morphology to a more traditional paradigm of a steeper underlying décollement ramp. The two paradigms predict different patterns of current deformation, but both at rates readily measurable with global positioning system (GPS). In this paper we review the current impasse which researchers from both sides of the debate have reached using methods of structural mapping, morphological analysis, spirit-leveling, seismicity, thermochronometry, cosmogenically-determined erosions rates, and thermokinetic modeling and propose that the addition of continuous geodetic measurements of surface deformation combined with elastic half-space modeling could help resolve the issue. To this end we deployed a network of 6 permanent GPS stations in the Nepal Himalaya in summer 2008 and have plans to expand to it to 16 stations. Preliminary model results demonstrate that within a couple years differences between the two paradigms should be discernable.
Pratt-Sitaula, B., Upreti, B. N., Melbourne, T., Miner, A., Parker, E., Rai, S. M., & Bhattarai, T. N. (2009). Applying geodesy and modeling to test the role of climate controlled erosion in shaping Himalayan morphology and evolution. Himalayan Geology, 30(2), 123-131.