地质通报2017，Vol.36Issue(6)：933-944,12.
西藏萨嘎地区仲巴微地体韧性滑脱剪切带40Ar-39Ar年龄及其地质意义
40Ar-39Ar ages of the ductile decollement shear zone in the Zhongba microterrane of Saga region, southwest Tibet, and their geological significance
摘要
Abstract
The ductile decollement shear zones are in Zhongba microterrane which lies between southern subbelt and northern subbelt in the western part of the Yarlung Zangbo suture zone.The determination of the activity time about the high strain tectonic belt can not only provide constraints for its formation evolution but also provide the important corroborative evidence for the India-Eurasia collision.The samples of muscovite and biotite mylonitic rock were collected from the different parts of deformation in the shear zone to analyze the chronology with the mica 40Ar-39Ar dating.The tested ages including 53.39±0.57Ma,39.45±0.42Ma and 29.41± 0.32Ma in three groups indicate that the shear zone has multi-period tectonic activities.Group one which represents the initial stage of the India-Eurasia collision is the age limit of the shear zone (minimum age).Thus the initial time of plate collision should be the end of the Late Cretaceous to the Early Eocene before 53.39±0.57Ma because the shear zone was the product of the initial collision.Group two which is the cooling age of muscovite that formed under the SN-trending shearing compressive stress represents the period of main collisions.Group three which is the biotite age that formed after the reslip of the shear zone slip at low temperature uplifting stage represents the period of post-collision.关键词
韧性滑脱剪切带/云母40Ar-39Ar年龄/多期次活动/板块碰撞时间/仲巴微地体Key words
ductile decollement shear zone/mica 40Ar-39Ar dating/multi-period activities/plates collision time/Zhongba microterrane分类
天文与地球科学引用本文复制引用
张斌,刘兴平,李随云,史锡理,卢海波,陈炜,李冰冰..西藏萨嘎地区仲巴微地体韧性滑脱剪切带40Ar-39Ar年龄及其地质意义[J].地质通报,2017,36(6):933-944,12.基金项目
中国地质调查局项目《西藏1∶5万牛库等四幅区域地质矿产调查》(编号:1212011221059) （编号:1212011221059）
