Potential Role of Strike-slip Faults in Opening up the South China Sea
Abstract
New radiometric dates of key rocks indicate that a remnant Early Cretaceous ocean (i.e. the Huatung Basin) is still preserved today east of the South China Sea (SCS) and west of the Philippine Sea Plate. Integrating regional geology of the SE Asia with the Huatung Basin, we can reconstruct a Mesozoic Huatung Plate east of the Eurasian continent. Furthermore, the history of the Huatung Plate allows us to propose a new hypothesis that the mechanism responsible for the SCS opening was raised from strike-slip faulting on the east. The hypothesis suggests that the SCS opening could highly relate with the strike-slip faulting inherited from Late Mesozoic structures onshore-offshore SE Cathaysia Block to develop rhombic-shape extensional basins en echelon on the thinned Eurasian continental crust in the Early Cenozoic. It was followed by sinistral strike-slip movements along the boundary between the Eurasian Plate and the Huatung Plate driven by oblique subduction of the Huatung Plate to the northwest coupled with slab pull force by southward subduction of the Proto-South China Sea to open up the triangle-shaped oceanic East Sub-basin in the Early Oligocene (33/34 Ma). Spreading ridge then propagated southwestward in the step-over segment between the Zhongnan-Lile and Red River strike-slip fault systems to open the triangle-shaped oceanic Southwest Sub-basin by 23 Ma. The plate boundary fault was subsequently converted as the Manila Trench when the Eocene Sierra Madre Arc of the Huatung Plate had moved from the south to its present latitude by the Middle Miocene.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.T51E0305H
- Keywords:
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- 8104 Continental margins: convergent;
- TECTONOPHYSICS;
- 8105 Continental margins: divergent;
- TECTONOPHYSICS;
- 8157 Plate motions: past;
- TECTONOPHYSICS;
- 8185 Volcanic arcs;
- TECTONOPHYSICS