Preprint Article Version 1 NOT YET PEER-REVIEWED

Crustal and Upper Mantle Density Structure Beneath the Qinghai-Tibet Plateau and Its Surrounding Areas Derived from EGM2008 Geoid Anomalies

Honglei Li 1,2,* and Jian Fang 1
  1. State Key Laboratory of Geodesy and Earth’s Dynamics, Institute of Geodesy and Geophysics, Chinese Academy of Sciences, Wuhan 430077, China
  2. University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
Version 1 : Received: 14 October 2016 / Approved: 15 October 2016 / Online: 15 October 2016 (08:25:13 CEST)

How to cite: Li, H.; Fang, J. Crustal and Upper Mantle Density Structure Beneath the Qinghai-Tibet Plateau and Its Surrounding Areas Derived from EGM2008 Geoid Anomalies. Preprints 2016, 2016100062 (doi: 10.20944/preprints201610.0062.v1). Li, H.; Fang, J. Crustal and Upper Mantle Density Structure Beneath the Qinghai-Tibet Plateau and Its Surrounding Areas Derived from EGM2008 Geoid Anomalies. Preprints 2016, 2016100062 (doi: 10.20944/preprints201610.0062.v1).

Abstract

As the most active plateau on the Earth, the Qinghai-Tibet Plateau has a complex crust-mantle structure. Knowledge of the distribution of such a structure provides information for understanding the underlying geodynamic processes. We obtains a three-dimensional density model of crustal and upper mantle beneath Qinghai-Tibet plateau and its surrounding areas from the residual geoid anomalies using the Earth Gravitational Model (EGM) 2008. We estimate a refined density model by iterations, using an initial density contrast model. We confirm that the EGM2008 mission products can be used to constrain the crust-mantle density structures. Our major findings are: (1). At 300-400 km depth, high-D anomalies terminate around Jinsha River Suture (JRS) in the central TP, suggesting that the Indian plate has been reached over the Bangong Nujiang Suture (BNS) and almost reach to the JRS. (2). On the eastern TP, low-D anomalies at the depth of 0-300 km together with high-D anomalies at 400-670 km further verified the current eastward subduction of Indian plate. The ongoing subduction provides forces to the occurrences of frequent earthquakes and volcano. (3). At 600 km depth, low-D anomalies inside the TP illustrate the existence of hot weak material beneath there, contributing to the external material inward-thrusting.

Subject Areas

Qinghai-Tibet Plateau; geoid anomaly inversion; crustal and upper mantle density construction

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