Pliocene-Quaternary crustal melting in central and northern Tibet and insights into crustal flow

Qiang Wang; Chris J Hawkesworth; Derek Wyman; Sun-Lin Chung; Fu-Yuan Wu; Xian-Hua Li; Zheng-Xiang Li; Guo-Ning Gou; Xiu-Zheng Zhang; Gong-Jian Tang; Wei Dan; Lin Ma; Yan-Hui Dong

doi:10.1038/ncomms11888

Pliocene-Quaternary crustal melting in central and northern Tibet and insights into crustal flow

Nat Commun. 2016 Jun 16:7:11888. doi: 10.1038/ncomms11888.

Authors

Qiang Wang^{1

2}, Chris J Hawkesworth^{3

4}, Derek Wyman⁵, Sun-Lin Chung^{6

7}, Fu-Yuan Wu⁸, Xian-Hua Li⁸, Zheng-Xiang Li⁹, Guo-Ning Gou¹, Xiu-Zheng Zhang¹, Gong-Jian Tang¹, Wei Dan¹, Lin Ma¹, Yan-Hui Dong¹

Affiliations

¹ State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China.
² CAS Center for Excellence in Tibetan Plateau Earth Sciences (CETES), Beijing 100101, China.
³ School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, UK.
⁴ Department of Earth and Environmental Sciences, University of St Andrews, North Street, St Andrews KY16 9AL, UK.
⁵ School of Geosciences, The University of Sydney, Sydney, New South Wales 2006, Australia.
⁶ Institute of Earth Sciences, Academia Sinica, Nangang, Taipei 11529, Taiwan.
⁷ Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
⁸ Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China.
⁹ ARC Centre of Excellence for Core to Crust Fluid Systems (CCFS) and the Institute for Geoscience Research (TIGeR), Department of Applied Geology, Curtin University, Perth, Western Australia 6845, Australia.

Abstract

There is considerable controversy over the nature of geophysically recognized low-velocity-high-conductivity zones (LV-HCZs) within the Tibetan crust, and their role in models for the development of the Tibetan Plateau. Here we report petrological and geochemical data on magmas erupted 4.7-0.3 Myr ago in central and northern Tibet, demonstrating that they were generated by partial melting of crustal rocks at temperatures of 700-1,050 °C and pressures of 0.5-1.5 GPa. Thus Pliocene-Quaternary melting of crustal rocks occurred at depths of 15-50 km in areas where the LV-HCZs have been recognized. This provides new petrological evidence that the LV-HCZs are sources of partial melt. It is inferred that crustal melting played a key role in triggering crustal weakening and outward crustal flow in the expansion of the Tibetan Plateau.

Publication types

Research Support, Non-U.S. Gov't