摘要
通麦地区片麻岩中锆石SHRIMP定年结果表明:①变质锆石和变质复合锆石的新壳U-Pb年龄为42Ma,属于中始新世,相当于陆陆碰撞的峰期时间,而印度和欧亚两个大陆开始碰撞的时间略早于42Ma;②变质复合锆石中的老核(继承锆石),有2个点U-Pb年龄为201Ma,相当于早侏罗世早期,表明通麦片麻岩是沉积岩变质的,其沉积岩的时代不会早于三叠纪;③文章最后对锆石成因类型及意义、片麻岩的时代和印度与欧亚两大陆碰撞的时间等问题进行了讨论。
The SHRIMP U-Pb dating of the gneiss in the Tongmai region shows that： ① the mean U-Pb age（42Ma） for the metamorphic zircon and the younger crust of metamorphic compound zircon is in Mid-Eocene epoch,which is consistent with the peak age of the continental-continental collision.The starting time of the India-Eurasia collision should be little earlier than 42Ma.② The oldest age for the older core of the compound metamorphic zircon（inherited zircon） is about 201Ma,equivalent to early Jurassic,indicating that the age of the sedimentary protolithic of the gneiss in the Tongmai region should be later than Triassic.③ The genesis and types of the zircon and their significance,the age of the gneiss,and the collision time of the India-Eurasia continents are discussed in the paper.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2009年第3期347-352,共6页
Acta Geologica Sinica
基金
国家自然科学基金重点项目(编号40534019)资助的成果
