摘要
祁漫塔格韧性剪切带是祁漫塔格蛇绿混杂岩带与北昆仑岩浆弧的区域主构造边界,对剪切带内花岗质糜棱岩中绢云母^(40)Ar-^(39)Ar法年龄测定,获得了(271.1±2.2)Ma的坪年龄,相应的^(36)Ar/^(40)Ar-^(39)Ar/^(40)Ar反等时线年龄为(270.5±3.7)Ma(MSWD=2.7),^(39)Ar/^(36)Ar-^(40)Ar/^(36)Ar正等时线年龄为(270.9±4.7)Ma(MSWD=0.22);坪年龄(271.1±2.2)Ma接近于绢云母矿物的形成年龄,也代表了祁漫塔格韧性剪切带的形成年龄。通过韧性剪切变形带内运动学特征的研究,表明剪切带具有右旋斜冲的性质。祁漫塔格韧性剪切带的形成与古特提斯洋的俯冲作用有关,是古特提斯洋向北俯冲造山过程的远程效应。
Qimantage ductile shear zone is the main tectonic boundary of Qimantage ophiolite belt and North Kunlun magmatic arc, we determine granitic mylonite in shear zone with sericite 40Ar_39 Ar meth- ods. Plateau age is 271.1 4- 2.2Ma,36 At/40 Ar-39 At/40 Ar reverse-isochron curve age is 270.5 ±4- 3.7 Ma （MSWD=2. 7）, and 39Ar/36Ar-40Ar/36Ar isoehron age is 270. 94-4.7Ma （MSWD=0.22） . Plateau age 271.14-2. 2Ma close to the age of mineral formation of sericite, it represents the formation age of Qiman- tage ductile shear zone. Through the ductile shear zone within the kinematic characteristics, dextral shear zone has the nature of Oblique filling. The formation of Qimantage ductile shear zone related Paleo-Tethys Ocean Subduction, is the remote effects of the process of Paleo-Tethys Ocean Northward subduction orog- eny.
出处
《西北地质》
CAS
CSCD
2012年第1期94-101,共8页
Northwestern Geology
基金
中国地质调查局项目“青海1∶5万乌兰乌珠尔-祁漫塔格地区八幅区域地质调查”(1212010610312)
