阿尔金北缘枕状玄武岩的地质特征及其锆石U-Pb年龄  

Geology and Zircon U-Pb Age of Pillow Basalt at Qiashikansoy in Northern Altun Tagh, W China

作　　者：修群业[1] 于海峰[2] 刘永顺[2] 陆松年[2] 毛德宝[2] 李惠民[2] 李铨[2] 

机构地区：[1]核工业北京地质研究院 [2]中国地质调查局天津地质矿产研究所,300170

出　　处：《地质学报》2007年第6期787-794,共8页Acta Geologica Sinica

基　　金：国家自然科学基金重点项目"我国古陆块对Rodinia全球超级大陆事件的响应"(编号40032010);国土资源大调查综合研究项目"中国西部前寒武纪重大地质事件群研究"(编号200313000060)资助成果

摘　　要：阿尔金山北缘恰什坎萨依出露的玄武岩具枕状、气孔和杏仁状构造,镜下多为间隐结构,岩石化学成分特点及REE等微迹元素显示洋岛玄武岩特征;其颗粒锆石U-Pb年龄为448.6±3.3Ma。该区玄武岩与相伴产出的蛇纹石化橄榄岩、辉长岩及硅质岩、粉砂岩等呈断层接触关系,它们共同组成了较标准的蛇绿岩。这为探讨阿尔金山的大地构造演化提供了新的证据。Basalt at Qiashikansoy on the northern margin of Altun Tagh, western China, occurred in pillow, gas holes and almonds structures, and usually had ophitic interstitial texture under microscope. It might be formed in an oceanic island environment, as shown by the features of petrochemical components, REE patterns and other trace elements of the basalt. Because the grains from the basalt are too small to be analyzed by SHRIMP, they can only be dated by the TIMS method. The zircon U-Pb age of 448.6±3.3 Ma may represent a compression setting of the Altun fault. The basalt, serpentinized periodtite, gahhro, silica rocks and silt rocks were separated by faults. These rocks appeared as slabs in cross section, and they constitute a substandard ophiolite. Both the geology and geochemistry and the age of zircon U-Pb dating of the ophiolite provided new evidence for the research of the tectonic evolution of Altun Tagh.

关 键 词：阿尔金 枕状玄武岩 蛇绿岩 地质特征 锆石U-PB年龄 

分 类 号：P588.145[天文地球—岩石学]