| 华南湘中南地区中生代构造变形特征及深部过程 |
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| 关键词:superimposed fold tectonic stress field Chenzhou–Linwu fault seismic reflection profile South China |
| 基金项目:财政部“深部探测技术与实验研究”专项之子课题(编号: Sinoprobe-08-01) |
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| Episodic Mesozoic Constructional Events of Central South China: Constraints from Lines of Evidence of Superimposed Folds, Fault Kinematic Analysis, Magma Geochronology and Seismic-reflection Profiling |
| The South China block (SCB), located in the convergence zones of the western Pacific subduction tectonic domain and Tethyan tectonic domain, has experienced complex tectonic processes, including the continent-continent collision caused by the closure of the Palaeo-Tethys Ocean, and the subduction of the Palaeo-Pacific plate. However, due to complex in-tracontinental deformation and abundant magmatism, there are serious divergences in the corresponding records of the tectonic transformation from Pa-laeo-Tethys to Palaeo-Pacific. We have analyzed the map-scale superimposed fold system developed in central SCB and also inverted the palaeo-stress field based on the fault-slip vectors. On this basis, the de-formation styles and superposition mechanism of two-stage folds were recovered to establish the tec-tonic stress field in early Mesozoic and tec-tono-magmatic events by combining the chronology of the accompanying syntectonic magma. The early E–W/WNW-trending folds and Triassic magmatic system were identified; these were controlled by the NE–SW-trending compressive stress field, to coordi-nate with the collisions between the SCB and the In-dochina block in the southwest, and the North China block in the north. The late NE/NNE-trending folds superimposed on the early folds in an orthogonal way to form a large-scale dome-basin superimposed fold system, which were controlled by the WNW–ESE-trending compressive stress field. Ac-cording to the strata relations involved in deformation and the chronology data of magmatic rocks, it could be determined that NE/ENE-trending folds would be formed during the Mid- to Late Jurassic, correspond-ing to the westward subduction events of the Pa-laeo-Pacific plate. The establishment of the large-scale superimposed fold styles and the identifi-cation of fold deformation in the Triassic and Jurassic are important for understanding the early Mesozoic tectonics of South China, and even for all East Asia continent. In particular, it can provide important tem-poral and spatial constraints to explain the complex deformation process and geodynamic settings of South China in the early Mesozoic. |
| LI Yong,DONG Shu-wen,HAN Bao-fu,ZHANG Yue-qiao.2017.Episodic Mesozoic Constructional Events of Central South China: Constraints from Lines of Evidence of Superimposed Folds, Fault Kinematic Analysis, Magma Geochronology and Seismic-reflection Profiling[J].Acta Geoscientica Sinica,38(s1):19-20. |
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