Mantle Driven Dynamic Uplift of Hangay Dome: New Seismological Constraints from Adjoint Tomography

Min Chen, Rice Univ-Earth Science, Houston, TX, United States, Fenglin Niu, University of Science and Technology of China, School of Earth & Space Sciences, Anhui, China, Qinya Liu, University of Toronto, Toronto, ON, Canada and Jeroen Tromp, Princeton University, Department of Geosciences, Princeton, NJ, United States
Abstract:
The origin and nature of Hangay Dome, an unusual large-scale doming structure in Central Mongolia, remains enigmatic, partly due to lack of knowledge on its underlying seismic structure. Here we present a new high-resolution multi-parameter seismic model derived from adjoint tomography, utilizing the full wavefield recorded by an unprecedented seismographic network in its surroundings. The new seismological constraints include Vs perturbation, the Vp/Vs ratio and radial anisotropy, (Vsh-Vsv)/Vs. We observe clear correlation between the high topography of the dome and regions with a low Vs and high Vp/Vs ratio down to 150 km. We also observe negative radial anisotropy (faster Vsv) at deeper asthenospheric depths (250 - 500 km) underlying positive radial anisotropy (faster Vsh) at shallow depths (< 250 km) right below the dome, and negative radial anisotropy at shallower depths (50 - 150km) on the flanks of the dome. These observations are consistent with a scenario that a deep asthenospheric upwelling arises from the mantle transition zone, producing decompression melting that feeds magmatism causing high topography of the area.
Back to: Earth System Dynamics of High Elevation Continental Interiors: From the Asthenosphere to the Biosphere Posters