喜马拉雅造山带东段错那地区高喜马拉雅结晶岩系的变质作用与构造意义

发布时间：2018-06-19 09:09

  本文选题：高级变质作用 + 部分熔融　； 参考：《岩石学报》2017年08期

【摘要】：位于造山带核部的高喜马拉雅结晶岩系是由印度大陆俯冲到亚洲大陆之下经历变质作用的产物,是研究喜马拉雅造山带形成与演化过程的理想载体。本文对造山带东段错那地区高喜马拉雅结晶岩系上部构造层位的正片麻岩进行了岩石学、相平衡模拟,锆石与独居石U-Pb年代学研究。研究结果表明这些岩石的峰期矿物组合为石榴石+斜长石+钾长石+黑云母+白云母+石英+钛铁矿,保留有深熔作用的结构特征。岩石中的石榴石具有生长成分环带。相平衡模拟表明,岩石的峰期变质条件为710~750℃和9.0~10.5kbar,具有一个顺时针型变质作用P-T轨迹,其进变质过程以升温、升压和部分熔融为特征,退变质作用为降温、降压过程。锆石与独居石U-Pb定年表明,这些正片麻岩具有510~490Ma的原岩年龄,和27~11Ma的退变质时间。本研究表明高喜马拉雅结晶岩系的上部构造层位经历了高角闪岩相变质作用与部分熔融,为造山带的构造演化提供了重要信息。
[Abstract]:The high Himalayan crystalline rock series located in the core of the orogenic belt is the product of metamorphism from the Indian continent subducting to the Asian continent and is an ideal carrier for studying the formation and evolution of the Himalayan orogenic belt. In this paper, the petrology, phase equilibrium simulation, zircon and monazite U-Pb chronology of the normal gneiss in the upper tectonics of the upper Himalayan crystalline series in the Dana area of the eastern part of the orogenic belt have been carried out. The results show that the peak mineral assemblage of these rocks is garnet plagioclase potassium feldspar biotite Muscovite quartz ilmenite retaining the structural characteristics of deep penetration. The garnet in the rock has a growth composition ring. The phase equilibrium simulation shows that the peak metamorphic conditions of the rocks are 710 ~ 750 鈩，

本文编号：2039362