Post-rift tectonic reactivation and its effect on deep-water deposits in the Qiongdongnan Basin, northwestern South China Sea
Mao, K.; Xie, X.; Xie, Y.; Ren, J.; Chen, H. (2015). Post-rift tectonic reactivation and its effect on deep-water deposits in the Qiongdongnan Basin, northwestern South China Sea. Mar. Geophys. Res. 36(2-3): 227-242. https://dx.doi.org/10.1007/s11001-015-9248-x
In: Marine Geophysical Researches. Reidel: Dordrecht. ISSN 0025-3235; e-ISSN 1573-0581, more
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| Author keywords |
Post-rift stage; Tectonic reactivation; Pre-existing faults; Magmaticintrusion |
| Authors | | Top |
- Mao, K., more
- Xie, X.
- Xie, Y.
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| Abstract |
The post-rift evolution of extensional basins is traditionally thought to be dominated by thermal subsidence due to cessation of the major fault activity during the post-rift stage. The Qiongdongnan Basin, which is located in the northwestern continental margins of the South China Sea, has exhibited significant deviations from typical post-rift characteristics. In the basin, a distinct tectonic reactivation occurred since the Late Miocene (11.6 Ma). Three notable aspects of the observed tectonic reactivation during the post-rift stage include, (1) pre-existing fault reactivation, (2) multiple large-scale magmatic intrusions, and (3) rapid post-rift subsidence. During this period the basin infill significantly changed in depositional environments shifting rapidly from littoral-neritic to bathyal-abyssal environments since Late Miocene. The pre-existing fault activity along the No. 2 fault of the basin resulted in the formation of initial shelf breaks and led to the development of continental slope. In addition, the pre-existing faults along the Central Depression zone created a small sub-basin with distinctive axial negative topography characteristics formed between structural highs. These geomorphological changes led to the formation of the Central Canyon. Large-scale magmatic intrusions occurred along the fault zone in the Central Depression of the basin during the post-rift stage. Those deviations, as evidenced from pre-existing fault reactivation, magmatic intrusions, and rapid post-rift subsidence in the Qiongdongnan Basin is believed to be related to the Hainan Plume event. |
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