论文部分内容阅读
阿尔金构造带西段的榴辉岩呈透镜状产于以角闪岩相矿物组合为特征的片麻岩中 .选择保存较好的榴辉岩分别进行Sm Nd和U Pb的同位素年代学测定 ,测得全岩 石榴石 绿辉石的Sm Nd等时线年龄为 ( 5 0 0± 1 0 )Ma ;4个颗粒的锆石U Pb同位素测定获得的表面年龄很好地落在一致线上 ,并得出其权重平均值为 ( 5 0 3.9± 5 .3)Ma .2种方法获得的基本一致的年龄数据反映了榴辉岩的峰期变质时代 ,从而表明了阿尔金构造带中加里东期与俯冲及陆 陆碰撞作用有关的山根的存在
The eclogite in the western segment of the Altyn Tagh Formation is lenticular and occurs in gneisses characterized by amphibolite facies mineral assemblages. The isotopic chronological measurements of Sm Nd and U Pb are selected for well-preserved eclogites , The Sm Nd isochron age of (5 0 0 ± 1 0) Ma was measured for the whole rock garnet, and the surface age obtained from the zircon U Pb isotope measurements of 4 grains falls well on the same line The average weight of the eclogites was (5 0 3.9 ± 5. 3) Ma. The basically same age data obtained by these two methods reflect the peak metamorphism of the eclogite, which indicates that the Caledonian And the subduction and land-continent collision related to the existence of the root of the mountain