朱阳关-夏馆断裂带构造变形的温压条件

文章对朱阳关-夏馆(简称朱-夏)断裂带形成时期的变形温压条件进行一系列研究.首先对石英和长石进行动态重结晶分析,得到朱夏断裂附近的变形温度为300～650 ℃,带中心温度较高,为500～650℃.越靠近构造带温度越高,往两侧递减,变形环境在绿片岩相到低角闪岩相之间.通过EBSD实验得到石英组构,岩石石英C轴组构分析结果点极密分布于边缘,可推断其变形温度为400～600 ℃.电子探针数据指示其变形温度为608.6 ℃,变质压力的上限为5161 bar,变质程度最高可达角闪岩相.研究结果反映出朱阳关夏馆断裂带是中温-中低压条件下形成的.

Temperature and pressure conditions of tectonic deformation of Zhuyangguan-Xiaguan fault belt

A series of studies have been made of the temperature and pressure conditions of tectonic deformation of Zhuyangguan-Xiaguan fault belt in its ductile deformation stage.Firstly,the deformation temperature near Zhu-Xia fault belt is obtained by the dynamic recrystallization analysis of quartz and feldspar,which is 300-650 ℃.The center temperature is higher,which is 500-650 ℃,and the temperature of the fault belt decreases to both sides.The deformation environment is between greenschist facies and amphibolite facies.Secondly,the EBSD test shows the quartz C-axis fabric,and most points of the analysis result of quartz C-axis fabric extremely close locate at the edge,thus it is deduced that the deformation temperature is 400-600 ℃.Finally,the electron microprobe data indicates that the deformation temperature is 608.6 ℃,the upper limit for the metamorphic pressure is 5 161 bar,and the degree of metamorphism is up to amphibolites facies.The results demonstrate that Zhuyangguan-Xiaguan fault belt is formed in conditions of medium temperature and low to medium pressure.