肥东花岗质岩脉的变形及年代学特征对郯庐断裂带早白垩世构造活动的指示  

Defromation features and zircon U-Pb dating of the granitic dikes from the Feidong area and its implications on the tectonic activity of Tan-Lu Fault Zone during Early Cretaceous

作　　者：韩雨[1] 牛漫兰[1] 

机构地区：[1]合肥工业大学资源与环境工程学院,合肥230009

出　　处：《岩石学报》2016年第4期1049-1066,共18页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(41172201)资助

摘　　要：郯庐断裂带肥东段位于大别造山带与苏鲁造山带之间。在肥东段西韦采石场内发育了大规模的北北东向左行走滑韧性剪切带和一条低角度的韧性滑脱正断层。走滑韧性剪切带为郯庐断裂带走滑活动的产物,低角度滑脱正断层则代表了伸展背景下的构造活动。低角度滑脱正断层上、下盘发育未变形和变形的岩脉,走滑韧性剪切带内外也发育有受剪切带活动而变形的岩脉。对采石场内岩脉的构造和同位素年代学研究表明,低角度韧性滑脱正断层在129～126Ma之间发生过剪切活动,走滑韧性剪切带的活动时间在125Ma之后。综合研究认为,郯庐断裂带的伸展活动可能开始于早白垩世早期（130Ma）,但在早白垩世并非一直处于伸展活动之中,125Ma之后的左行走滑活动很可能发生在早白垩世的晚期。A large-scale NNE-striking sinistral ductile shear belts and a low angle ductile normal fault are exposed in Xiwei area from the Feidong segment of the Tan-Lu Fault Zone that is located between Dabie orogen and Sulu orogen. The strike-slip ductile shear belt formed from the activity of the Tan-Lu Fault Zone,and the low angle ductile normal fault were developed in extensional tectonic settings. There are a great deal of granitic dikes in the strike-slip ductile shear belt and both sides of the normal fault,including deformed and undeformed dikes. Studies on structure and isotope chronology of these dikes indicate the low angle normal fault happened during 129 ～ 126 Ma,but the forming time of the strike-slip ductile shear zone is later than 125 Ma. Combined with previous research results,the extensional activities of Tan-Lu Fault Zone started as early as 130 Ma,but it did not last during the Early Cretaceous,a sinistral strike-slip could take place in the Late Cretaceous.

关 键 词：伸展构造 走滑活动 锆石U-PB 变形岩脉 郯庐断裂带 

分 类 号：P597.3[天文地球—地球化学]