Crustal Modifications Beneath the Central Sunda Plate Associated with the Indo-Australian Subduction and the Evolution of the South China Sea

Abstract

To decipher possible crustal modifications associated with complex tectonics in SE Asia, we have conducted a systematic receiver function investigation beneath the central Sunda plate mainly including Borneo, the Malay Peninsula, Sumatra and part of the South China Sea (SCS). Well-determined observations from a total of 22 stations reveal a laterally heterogeneous crust with thickness ranging from 22.8 km to 39.1 km and Vp/Vs values varying from 1.68 to 2.12. An increasing pattern of Vp/Vs ratios towards the Sumatra fault and the Toba Caldera indicates significant modifications of crustal composition possibly due to melting from the Indo-Australian subduction. Crustal compositions beneath the Malay Peninsula are determined to be mostly felsic to intermediate rocks. Crustal thinning at the Sibumasu terrane relative to the East Malay block is revealed and may be attributed to joint effects of Late Paleogene rifting and a subsequent thermal anomaly. The southwards subduction of the hypothetical Proto-SCS may have contributed to the revealed magma intrusion and thinned crust beneath NW Borneo, and developed an accretionary setting at NE Borneo. The cessation of the Proto-SCS subduction further promotes collision between NE Borneo and Nansha block, which is supported by the observed crustal thickening. Thinned crust at the southern margin of the SCS basin is further confirmed as continental in origin and has been altered by possible post-spreading volcanisms.

Department(s)

Geosciences and Geological and Petroleum Engineering

Research Center/Lab(s)

Center for High Performance Computing Research

Comments

National Natural Science Foundation of China, Grant 41606043

Keywords and Phrases

Crustal modification; Receiver function; South China Sea; Sumatra Subduction; Sunda plate

International Standard Serial Number (ISSN)

0031-9201

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2020 Elsevier, All rights reserved.

Publication Date

01 Sep 2020

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