Wedge tectonics in South China: constraints from new seismic data

Tingzi Li, Mingming Jiang*, Liang Zhao, Weihua Yao, Ling Chen, Yang Chu, Baolu Sun, Yinshuang Ai, Bo Wan, Klaus Gessner, Huaiyu Yuan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Collisional orogens form when tectonic forces amalgamte fragments of Earth's continental lithosphere. The sutures between individual fragments, or terranes, are potential sites of weakness that facilitate subsequent continental breakup. Therefore, the lithospheric architecture of collisional orogens provides key information for evaluating the long-term evolution of the continental interior: for example, the South China Block (SCB), where the tectonic history is severely obscured by extensive surface deformation, magmatism, and metamorphism. Using new passive-source seismic models, we show a contrasting seismic architecture across the SCB, with three prominent crustal dipping structures across the Jiangnan Orogen. Combined with constraints from multi-disciplinary regional geophysical datasets, these pronounced dipping patterns are interpreted as relict wedge-like lithospheric deformation zones initiated in the fossil collisions that assembled the Yangtze Block and the SCB. The overall trend of these tectonic wedges implies successive crustal growth along paleo-continental margins and is indicative of northward subduction and docking of accretional terranes. In contrast, no such dipping structures are preserved in the Cathaysia Block, indicating a weak and reorganized lithosphere. The variations in the deformation responses across the SCB reflect the long-term modifications of the lithosphere caused by prolonged collision and extension events throughout the tectonic history of the SCB. Our results demonstrate the critical roles that suture zones played in the successive growth and evolution of the continental lithosphere.

Original languageEnglish
Pages (from-to)1496-1507
Number of pages12
JournalScience Bulletin
Volume67
Issue number14
Early online date13 May 2022
DOIs
Publication statusPublished - 30 Jul 2022

Keywords

  • Lithosphere architecture
  • Seismic receiver functions
  • Ambient noise tomography
  • South China Block
  • Wedge tectonics

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