阿尔金断裂早期走滑运动方向及其活动时间探讨  

The Initial Shear Sense of the Allun Fault and Its Timing

作　　者：周勇[1] 潘裕生[1] 

机构地区：[1]中国科学院地质研究所,北京100029

出　　处：《地质论评》1999年第1期1-9,共9页Geological Review

基　　金：国家攀登计划青藏项目(编号A29)资助

摘　　要：有关阿尔金断裂的地质问题长期存在争论,尤其是有关活动时间的观点最多,运动方向也有不同看法。本文阐述了阿尔金断裂的早期左旋走滑运动。在元古宙地层中产出的大型弧形构造、流变褶曲形态完整而清楚,同时镜下的显微构造观察和岩组分析,为进一步确定阿尔金断裂的早期左旋走滑运动提供了充分证据。其初始活动时间至少在870Ma前。左旋走滑运动的确定对弄清阿尔金断裂的发展演化和矿产预测具有意义。This paper deals with the initial shear sense of the Alum strike-slip fault. The ductile and plastic structures, including flow folds, gneissosity, augen structures. Domino structures. S-C fabrics and quartz c-axis fabrics, occurring in Proterozoic rocks in the Altun Mountain area are well preserved. The sinistral movement is fairly justified by the integration of the microstructures and petrofabric studies (quartz c-axis fabrics). The initial sinistral sense of displacement probably took place in Meso- and Neoproterozoic time. K-feldspar from streaky-banded migmatized am-phibole gneiss yielded a K-Ar age of 877. 3±26. 3 Ma,implying that the Altun faulting started in early Neoproterozoic time or earlier. The determination of initial sinistral displacement of the Al-tun fault is not only theoretically significant in studying the evolution of the Altun fault, but also valuable to mineral and oil prospecting.

关 键 词：阿尔金断裂 塑性变形 走滑运动方向 断层 

分 类 号：P542.3[天文地球—构造地质学]