江南造山带中段地壳结构特征——来自武宁—吉安深反射地震随机介质相关长度分析的认识 |
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关键词:middle part of the Jiangnan orogenic belt correlation length Moho surface fault boundary metallogenic channel |
基金项目:中国地质调查局地质调查项目(编号: DD20190012; DD20221643);国家自然科学基金项目(编号: 92062108; 42074099; 41630320) |
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摘要: |
Crustal Structure Characteristics of the Middle Part of Jiangnan Orogenic Belt: Insights from Random Medium Correlation Length Analysis of Wuning–Ji’an Deep Seismic Reflection Profile |
The Jiangnan orogenic belt is located in the middle of the Yangtze and Cathaysia blocks. It has experienced complex tectonic movements and deformations owing to the multi-stage collision, cracking, and reconstruction processes of the South China block and its periphery. During the Mesozoic era, it was affected by regional tectonic-magmatic events. The occurrence of the “big explosion” of mineralization is important in the study of deep intracontinental processes and mineralization. The Jiangnan orogenic belt is affected by factors such as sedimentary coverage and low exposure, and the crustal structure, deep processes, and boundary ranges of the middle part of the Jiangnan orogenic belt are still controversial. To further improve the understanding of the Mesozoic deep tectonic background, dynamic process, and mineralization in the middle part of the Jiangnan orogenic belt, in this study, we used the Wuning–Ji’an deep reflection seismic data to calculate the random medium parameters and obtain the correlation length profiles. The results showed that the thickness of the crust in the middle part of the Jiangnan orogenic belt gradually decreased from north to south along with the profile. Combined with the results of previous studies, it is speculated that the study area was controlled by the extensional tectonic system in the late Yanshanian period. The upwelling gradually weakened from south to north owing to the upwelling of the mantle. In addition, the polarities of the deep and large faults of the Yifeng–Jingdezhen fault were revealed, further proving that the Pingxiang–Guangfeng fault is the boundary between the middle part of the Jiangnan orogenic belt and Cathaysia block. Finally, the influence of Mesozoic regional structure on mineralization was comprehensively analyzed, and it is believed that under the background of extensional structure, the upwelling of mantle-derived material along the fault controlled the formation of gold, tungsten, and other deposits in this area. |
LIU Jia-hao,YONG Fan,LIU Zhen-dong,ZHANG Hui,YAN Jia-yong,RUAN Xiao-min,GAO Feng-xia,CHEN Chang-xin.2022.Crustal Structure Characteristics of the Middle Part of Jiangnan Orogenic Belt: Insights from Random Medium Correlation Length Analysis of Wuning–Ji’an Deep Seismic Reflection Profile[J].Acta Geoscientica Sinica,43(6):803-816. |
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