下扬子地区汤口断裂带构造特征、期次及动力学探讨  

Characteristics,deformation stages and related dynamics of the Tangkou fault zone in Lower Yangtze area

作　　者：王朝[1] 李阳[2] 陶威 沈仕豪 邓佳良 王耀 储东如[1] Wang Chao;Li Yang;Tao Wei;Shen Shihao;Deng Jialiang;Wang Yao;Chu Dongru(Geological Survey of Anhui Province,Hefei 230001;State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069;School of Resources and Civil Engineering,Suzhou University,Suzhou,Anhui 234099)

机构地区：[1]安徽省地质调查院,合肥230001 [2]大陆动力学国家重点实验室,西北大学地质学系,西安710069 [3]宿州学院资源与土木工程学院,安徽宿州234099

出　　处：《地质科学》2023年第3期764-784,共21页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：中国地质调查局项目“安徽1∶50 000南陵县等5幅区域地质矿产调查”(编号:12120113069200)资助。

摘　　要：汤口断裂带是下扬子地区一条北东—北北东向的控岩、控矿断裂,该断裂几何学、运动学的研究对认识下扬子地区燕山期以来构造演化具有重要意义。详细的构造解析表明,该断裂带至少经历了4期构造变形,分别是中侏罗世—早白垩世早期的逆冲挤压、早白垩世中期—古新世的伸展拉张、始新世—渐新世的右行平移和中新世—中更新世的左行走滑。根据断层面擦痕的矢量反演以及断裂的野外切割关系,我们认为汤口断裂带多期次构造变形对应的区域应力场分别为北西—南东向挤压、北西—南东向伸展、近东西向挤压和近南北向挤压。燕山期以来汤口断裂带的形成和演化主要与华南陆块多板块汇聚挤压的构造环境有关,包括伊泽奈崎板块和太平洋板块向欧亚板块之下的先俯冲碰撞、后拉张以及新生代印度—澳大利亚板块向北碰撞后产生的多方向应力作用。The Tangkou fault is one of the rock and ore‑controlling tectonic belt with NE‑NNE trending in Lower Yangtze region,which can provide crucial information for understanding the tectonic evolution of the Lower Yangtze region by study the geometry and kinematics since Yanshanian.Detailed structural analysis show that the fault zone underwent at least four‑stage deformations,including inverse compression occurred at the Middle Jurassic to the earliest Early Cretaceous,extensional fault during the Middle Early Cretaceous to Paleocene,dextral strike‑slip changed from Eocene to Oligocene,and left‑lateral trans‑pression at the Miocene to Middle Pleistocene.Based on the analysis of fault slickensides and the tectonic superposition relationship,the regional stress field corresponding to the multi‑stage tectonic deformation of Tangkou fault zone are NW‑NE compression,NW‑NE extension,near EW compression and near S‑N compression respectively.The formation and evolution of the Tangkou fault belt since Yanshanian is mainly related to the tectonic setting of the converging and compression of the South China continental block,including the subduction and collision of Izanagi Plate and paleo‑Pacific Plate to the Eurasian Plate,expansion of the Pacific Plate,and collided by Indo‑Australian Plate in Cenozoic.

关 键 词：汤口断裂带 构造演化 动力学背景 下扬子地区 

分 类 号：P542[天文地球—构造地质学]