南陵—宣城地区晚中生代构造应力场及其地质意义  

Tectonic stress field of Late Mesozoic in Nanling-Xuancheng area and its geological significance

作　　者：周宇章[1] 王勇生[2] 曹亮[1] 白桥 田自强 杜辉 ZHOU Yuzhang;WANG Yongsheng;CAO Liang;BAI Qiao;TIAN Ziqiang;DU Hui(Public Geological Survey Management Center of Anhui Province, Hefei 230091, China;School of Resources and Environmental Engineering, Hefei University of Technology, Hefei 230009, China)

机构地区：[1]安徽省公益性地质调查管理中心,安徽合肥230091 [2]合肥工业大学资源与环境工程学院,安徽合肥230009

出　　处：《合肥工业大学学报（自然科学版）》2021年第5期672-678,共7页Journal of Hefei University of Technology：Natural Science

基　　金：国家重大研发计划资助项目(2016YFC0600209);安徽省国土资源科技资助项目(2016-K-4)。

摘　　要：文章选择南陵—宣城地区早白垩世火山岩及中三叠统南陵湖组灰岩中发育的断层,利用擦痕计算应力场的方法获得了5期应力场,由老到新分别为WNW—ESE向拉张、最大压应力σ1近垂向的拉张、NW—SE向挤压、NNW—SSE向拉张及ENE—WSW向挤压。利用断层面上多组擦痕的叠加关系、应力场数据自身特征以及区域构造特征,得到上述5期应力场分别对应于早白垩世早期、中期2期拉张,晚白垩世初挤压,晚白垩世—古近纪拉张及新近纪挤压。早白垩世拉张早期表现为古太平洋板块俯冲方向改变形成的伸展背景,随后大规模岩浆活动向上侵位形成的底辟作用加强了伸展背景。研究成果对于查明矿床赋存状态及确定找矿方向均有一定的指示意义。In this paper,stress orientation was computed from fault-slip data for faults in the Early Cretaceous volcanic rocks and the limestone of the Middle Triassic Nanlinghu Formation of the Nanling-Xuancheng area.Five stress fields were obtained and are WNW-ESE extension,extension with a steep principal compression direction(σ1),NW-SE compression,NNW-SSE extension and ENE-WSW compression,respectively.According to superposition relation of slickensides on a same fault plane,the characteristics of the stress field data and the regional tectonic features,a conclusion can be drawn that the five stress fields correspond to two stages of extension in the early and middle stage of the Early Cretaceous,the earlier Late Cretaceous compression,the Late Cretaceous-Paleogene extension and the Neogene compression,respectively.For the Early Cretaceous extension,subduction direction change of the Pacific Plate resulted in extension in the East China firstly,and then large-scale magmatism enhanced this extension.The conclusion is valuable for finding out occurrence state of ore deposits and effective prospecting.

关 键 词：南陵-宣城地区 早白垩世火山岩 三叠系灰岩 断层 应力场 

分 类 号：P548[天文地球—构造地质学]