New images of complex structures underneath the Tibetan Plateau

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Abstract

The Tibetan Plateau contains some of the highest mountains in the world and was formed by the collision between the Indian and Eurasian plates beginning around 55 million years ago. Curious about how such elevated terrains form, Yue et al. used data collected from a seismic experiment conducted between 2007 and 2009 to image the complex three-dimensional geometry of the crust and upper mantle in northeastern Tibet. The scientists' results detected the interaction between components of thrust and subduction, shed light on the conditions surrounding crustal loading, and located mantle discontinuities and small-scale mantle convection. Despite the thick crust of the plateau, which can reach depths of 65–75 kilometers, the authors were able to capture for the first time major vertical offsets (ranging from 10 to 20 kilometers) in the Mohorovičić discontinuity, the boundary between the crust and the mantle underlying the region. These offsets, along with the presence of other structures, bear testament to the intricate evolution of the Tibetan Plateau; the authors posit different scenarios on the history of this evolution, including the presence of buried remnant slabs of possible oceanic origin that continue to sink and create mantle eddies. (Journal of Geophysical Research-Solid Earth, doi:10.1029/2011JB008545, 2012)

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