| 桂东北地区鹰扬关韧性剪切带的厘定及其构造意义 |
| |
| 关键词:magnetic fabric quartz EBSD fabric hydrothermal zircon ductile shear zone Yingyangguan area of northeastern Guangxi |
| 基金项目:国家自然科学基金项目(编号: 42072259; 42162018);广西自然科学基金项目(编号: 2022GXNSFAA035570; 2019GXNSFDA245009) |
|
| 摘要点击次数: 1097 |
| 全文下载次数: 752 |
| 摘要: |
| Discovery of Yingyangguan Ductile Shear Zone in Northeastern Guangxi and Its Tectonic Significances |
| Based on macro-micro structure, magnetic fabric, hydrothermal zircon and quartz EBSD fabric, the Yingyangguan ductile shear zone was determined and its tectonic significance is discussed. The Yingyangguan ductile shear zone has typical macro-micro structural characteristics, such as mylonite, stretching lineation, S-C fabric, rotating porphyry system, domino structures, pressure shadow structure and dynamic recrystallization of quartz. Magnetic fabric measurement and field geological survey showed that the Yingyangguan ductile shear zone extends over 40 km in NNE direction and is 2.5–8 km wide. The extremely dense point occurrence of the C folication of the mylonite is 127°∠50°, and the occurrence of extremely dense points of magnetic foliation is 107°∠83°. Analysis of the macro-micro structure showed that the Yingyangguan ductile shear zone has kinematic properties of early sinistral thrust shear and late dextral normal slip shear. Quartz EBSD fabric analysis revealed that the Yingyangguan ductile shear zone is characterized by late mid-low temperature deformation (400–550 ℃) superimposed on early mid-high temperature deformation (550–650℃). The geochronology showed that the age of the early sinistral thrust shear is (441.1±2.3) Ma, and the age of late dextral normal slip shear is later than 420 Ma. The time limit of regional tectonic stress from compression to extension is 420 Ma. Analysis of the magnetic fabric, quartz EBSD fabric, and hydrothermal zircon dating, combined with regional geological data, revealed that the Yingyangguan ductile shear zone formed in the tectonic background of the collision of the Cathaysia block from the SE to the Yangtze block. In the early stage of extrusion and collision, flattening strain was generated and mid-high temperature sinistral thrust shear was formed. After the late orogenic extension, tensile strain was generated, and dextral normal slip shear was formed at mid-low temperature. The strain characteristics, deformation temperature, deformation age, and dynamic setting of the Yingyangguan ductile shear zone provide new data that improve the understanding of Caledonian tectonic movement in South China. The above understanding of the Yingyangguan ductile shear zone may be related to the orogeny of the Yangtze and Cathaysian blocks in the Early Paleozoic, rather than being the product of tectonic mélange. |
| QIN Ya,FENG Zuo-hai,WU Jie,XUE Yun-feng,HU Qiao-fan,BAI Yu-ming,ZHOU Peng-cheng.2023.Discovery of Yingyangguan Ductile Shear Zone in Northeastern Guangxi and Its Tectonic Significances[J].Acta Geoscientica Sinica,44(3):434-454. |
| 查看全文 查看/发表评论 下载PDF阅读器 |
|
|
|
|
|