Structural and chronological constraints on a Late Paleozoic shortening event in the Yanshan Tectonic Belt  

作　　者：LIN ShaoZe ZHU Guang YAN LeJia SONG LiHong LIU Bei 

机构地区：[1]School of Resource and Environmental Engineering,Hefei University of Technology

出　　处：《Chinese Science Bulletin》2013年第32期3922-3936,共15页

基　　金：supported by the National Natural Science Foundation of China (91214301)

摘　　要：Early deformation history of the Yanshan Tectonic Belt is an unsolved,important issue.We report early structures and their dating results in basement rocks south of the Kalaqin metamorphic core complex.The basement deformation zone is characterized by WNW-ESE steep gneissosity,WNW-ESE shallow mineral elongation lineation and many intrafolial or isoclinal folds.Many kinematic indicators show that it is a WNW-ESE steep,ductile sinistral deformation zone.LA-ICPMS zircon dating gives a crystallization age of 271 Ma for tatolly transposed,deformed monzonite granite dyke and crystallization ages of 251–250 Ma and210 Ma for undeformed dyke,stock and pluton.The dating results demonstrate that the deformation related to regional shortening took place between 271 and 251 Ma,i.e.Middle-Late Permian.Combined with previous dating results for post-orogenic magmatism in the Yanshan Tectonic Belt,it is inferred that the shortening-related deformation happened in Middle Permian(271–260 Ma).Recent studies suggest that collision along the Solonker Suture took place in Middle Permian,and is then followed by post-collision extenion in Late Permian.We propose that the intense shortening deformation of the Middle Permian in the Yanshan Tectonic Belt belongs to foreland deformation along the norterhn margin of the North China Craton which is caused by continent-continent collision in the Xing-Meng Orogen.The belt was then oriprinted by shortening deformation of the Yanshanian Movement.Early deformation history of the Yanshan Tectonic Belt is an unsolved, important issue. We report early structures and their dating results in basement rocks south of the Kalaqin metamorphic core complex. The basement deformation zone is characterized by WNW-ESE steep gneissosity, WNW-ESE shallow mineral elongation lineation and many intrafolial or isoclinal folds. Many kinematic indicators show that it is a WNW-ESE steep, ductile sinistral deformation zone. LA-ICPMS zircon dating gives a crystallization age of 271 Ma for tatolly transposed, deformed monzonite granite dyke and crystallization ages of 251-250 Ma and 210 Ma for undeformed dyke, stock and pluton. The dating results demonstrate that the deformation related to regional shortening took place between 271 and 251 Ma, i.e. Middle-Late Permian. Combined with previous dating results for post-orogenic magmatism in the Yanshan Tectonic Belt, it is inferred that the shortening-related deformation happened in Middle Permian （271-260 Ma）. Recent studies suggest that collision along the Solonker Suture took place in Middle Permian, and is then followed by post-collision extenion in Late Permian. We propose that the intense shortening deformation of the Middle Permian in the Yanshan Tectonic Belt belongs to foreland deformation along the norterhn margin of the North China Craton which is caused by continent-continent collision in the Xing-Meng Orogen. The belt was then oriprinted by shortening deformation of the Yanshanian Movement.

关 键 词：燕山构造带 早期结构 时序约束 晚古生代 LA-ICP-MS 燕山造山带 事件 中二叠世 

分 类 号：P542[天文地球—构造地质学] TU528.02[天文地球—地质学]