摘要

The Qinzhou-Lingshan structural zone located in the southern part of the Qinzhou-Hangzhou junction belt in South China, is a large tectonic-magmatic active belt formed in Mesozoic. Structural analysis shows that the Lingshan section of the Qinzhou-Lingshan structural zone is a combination of strike slip structure, thrust nappe structure and a series of extensional structure. In the early stage, the Qinzhou-Lingshan structural zone has both strike slip and thrust characteristics, showing a group of parallel or branch composite strike slip faults on the plane, and a positive flower structure converging to the deep on the profile. In the middle stage, the Qinzhou-Lingshan structural zone overthrust the Liuwandashan granite body onto the autochthonous Paleozoic strata, showing an northwestward arc-shaped composite fault on the plane, and a thrust nappe structure composed of the front and back margin nappe type ductile shear zone and Lenticular granite fault block on the profile. In the late stage, the Qinzhou-Lingshan structural zone changed from compression-thrust deformation to post-orogenic extensional deformation, during which the tensional dike swarms, the extensional ductile shear zone, and the large tensional fault zone developed. The characteristics, transformation and evolution mechanism of the tectonic deformation in the zone reveal that under the geological background of the closure of the Qinlian-Luoding Aulacogen in the late Paleozoic, the Yangtze block and the Cathaysian block underwent oblique amalgamation-intraplate orogeny along the Lingshan section of the Qinzhou-Lingshan structural zone in the Mesozoic. The above understanding has important geological significance for understanding the closure of the Qinlian-Luoding Aulacogen, the demarcation and amalgamation process of the Yangtze block and the Cathaysian block, the dynamic mechanism and evolution of intraplate orogeny in South China, the tectonic emplacement of the Liuwandashan Indosinian granitic batholith, and the nature of the Shiwandashan Basin. ? 2023 Science Press.

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