甘新交界红柳河蛇绿岩形成和侵位年龄的准确限定及大地构造意义  

Accurate constraint on formation and emplacement age of Hongltuhe ophiolite,boundary region between Xinjiang and Gansu Provinces and its tectonic implications.

作　　者：张元元[1] 郭召杰[1] 

机构地区：[1]造山带和地壳演化教育部重点实验室,北京大学地球与空间科学学院,北京100871

出　　处：《岩石学报》2008年第4期803-809,共7页Acta Petrologica Sinica

基　　金：国家重点基础研究规划项目课题(2007CB411305和2001CB409804);国家自然科学基金项目(40572123)的资助

摘　　要：采用锆石SHRIMP U-Pb同位素定年方法,获得新甘交界红柳河蛇绿岩中的堆晶辉长岩年龄为516.2±7.1Ma,代表了红柳河蛇绿岩的形成年龄;侵入到红柳河蛇绿岩中未变形变质的黑云母花岗岩的年龄为404.8±5.2Ma,限定了红柳河蛇绿岩侵位的上限。作为南天山洋壳的残骸,红柳河蛇绿岩新的可靠年龄数据表明,南天山洋在早寒武世已经开始形成,并于早泥盆世埃姆斯阶之前在红柳河地区已经闭合。上述洋盆演化过程对进一步研究东天山的大地构造演化具有重要的意义。The SHRIMP zircon U-Pb dating of cumulate gabbro in Hongliuhe Ophiolite is 516.2±7.1Ma, recording the generation of the oceanic crust. The zircon U-Pb age of granite without deformation and metamorphism which intruded into the ophiollte is 404. 8 ± 5. 2Ma, which gives the upper limit for the emplacement age of the Hongliuhe ophiolite. As Hongliuhe ophiolite is the remnant of south Tianshan oceanic crust, these age data indicate that the south Tianshan oceanic crust formed as early as late Early Cambrian, and closed before Emsian in Hongliuhe area, which is significant for the tectonic evolution of east Tianshan.

关 键 词：红柳河蛇绿岩 锆石SHRIMP U—Pb年龄 构造演化 

分 类 号：P588.125[天文地球—岩石学] P597.3[天文地球—地质学]