Abstract: The Tanlu fault zone extending toward northeast China is branched into three subdivison parts. They are Yilan-Yitong,Mishan-Dunhua and Siping-Changchun faults. According to the isotopic chronological determination,the Rb-Sr isochron age of the diabase whole rock within the fault zone is (100±5.9)Ma,the ⁴⁰Ar/³⁹Ar plateau age of the augite is 105Ma. The ⁴⁰Ar/³⁹Ar plateau age of biotite mineral selected from the fault breccia and schists (mica quartz schists) within the Yilan Yitong fault zone is (100±1)Ma and (105.5±1.2)Ma～(95.7±1.8)Ma,respectively. In this region,in view of the outcrop investigation and comparison of different strata,strain calculation,the fault displacement is about 4km,or not more than 10km which is far less than the general estimation that the Tanlu fault zone is displaced more than 500km (Xu,1984). In this part,deformation of the fault is not very intensive,only cutting the Quantou formation (122Ma) of the lower Cretaceous system. Within the fault zone,the fault gouges developed less than 0.5m width. All of the evidence illustrates that the sinistral strike slip occurred during the time of 100Ma,i.e.,the end of early Cretaceous early of late Cretaceous. Activities of this part of the Tanlu fault zone affect the neighbouring basins where inverted structures occur. It is suggested that the strike-slip movement along the Tanlu fault of this part occurred on the basis of counterclockwise rotation of the eastern Asia continent and is associated with the subduction of the Pacific plate which induced upwelling of the upper mantle.

Key words: Tancheng Lujiang fault, Isotopic age dating, Fault slip, Pacific plate 

摘要： 郯庐断裂带在中国东北地区延伸,切过辽河盆地东部坳陷后分为依兰-伊通、密山-敦化和四平-长春三条断裂。在依兰-伊通断裂带内利用⁴⁰Ar/³⁹Ar法测得断层岩(云母石英片岩)中黑云母单矿物的年龄为(100±2.3)Ma.同时测得断裂带内辉绿岩的Rb-Sr全岩等时线年龄(100±5.9)Ma,辉石的⁴⁰Ar/³⁹Ar坪年龄为105Ma.从依兰-伊通断裂错开中生代花岗岩体、古生界地层、白垩系泉头组的露头对比,以及断裂带内应变测量等获得区内断层的走滑距离为4km左右。断层切过下白垩统泉头组(122Ma,K-Ar法)并被上白垩统嫩江组所覆盖。这段走滑断层的活动对邻近盆地产生了影响,造成盆地中的反转构造。该走滑断层是在中国东部地区逆时针方向的旋转运动基础上形成的,并与俯冲的西太平洋板块及其引起的上地幔物质运动有关。

关键词: 郯庐断裂带, 同位素年龄测定, 断层滑动, 太平洋板块