The School of Earth and Atmospheric Sciences Presents Dr. Karl Lang, Queens College, City University of New York
Diagnosing a Tectonic Aneurysm: Observations from the Eastern Himalaya
The evolution of mountain landscapes reflects complex interactions between tectonic processes transferring mass within the Earth’s interior and erosional processes redistributing mass across Earth’s surface. The eastern and western ends of the Himalayan mountain belt host exceptionally dynamic landscapes with a localized concurrence of steep topography, elevated geothermal gradients and extremely rapid rock exhumation.
The Tectonic Aneurysm hypothesis predicts that such dynamic landscapes reflect a thermo-mechanical feedback arising from sustained erosion at the point where a steep Himalayan tributary captured a large, high-elevation river system.
My research has critically evaluated this hypothesis by independently reconstructing the paleo-river drainage pattern and source-area exhumation history of the eastern Himalaya with a combination of geochronology and thermochronology of detrital minerals preserved in the peripheral sedimentary basin. Detrital mineral analyses support the development of a thermo-mechanical feedback between 5-7 million years ago, but also require any river reorganization (e.g. the capture of a high-elevation river system by a Himalayan tributary) to predate feedback development by at least 8 million years.
My results suggest that feedback development was unrelated to river capture, but may be alternatively explained by localized tectonic uplift from folding or tearing of the subducting Indian Plate.
Bio: Karl is a broadly trained geologist with interests spanning areas of tectonics, geomorphology and sedimentology; and expertise in low-temperature thermochronology. His research reconstructs the evolution of tectonically active landscapes from the sedimentary record they leave behind. He has worked in the eastern Himalaya, Southern Alps of New Zealand, Chilean coastal cordillera, and in several locations across the American west. He has a PhD from the University of Washington in Seattle and a BSc from the College of William and Mary in Virginia. He is currently an Assistant Professor at the Queens College campus of the City University of New York.