【摘要】 对产于布尔根大型剪切带中的科克萨依和阿拉塔斯2个金矿含金绢英质糜棱岩中的云母类矿物进行了连续激光阶段升温Ar-Ar法同位素测年,获得坪年龄分别为(274.5±2.2)Ma和(282.6±2.2)Ma,对应的等时线年龄分别为(275.8±5.2)Ma和(283.1±5.2)Ma,表明含金剪切带韧-脆性剪切活动的时代以及金成矿时代为早二叠世初。结合区域地质资料说明,布尔根含金剪切带的成生演化主要受早二叠世(290～270Ma)西伯利亚板块南缘巨型额尔齐斯剪切带区域性左行韧性剪切相伴的构造-岩浆热事件控制,其地球动力学背景为造山带构造演化的后碰撞伸展构造环境。更多还原

【Abstract】 Through continuous laser stepwise heating 40Ar/39Ar dating of two mica samples from auriferous phyllic mylonite of the Kekesayi and Alatasi gold deposits hosted in the Bu’ergen shear zone,the authors obtained plateau ages of 274.5±2.2 and 282.6±2.2 Ma and corresponding isochron ages of 275.8±5.2 and 283.1±5.2 Ma for the two deposits respectively.These ages suggest that the ductile-brittle shear of the Bu’ergen shear zone and formation of gold deposits occurred at the beginning of the Early Permian.These chronological data combined with regional geological data show that the formation and evolution of the Bu’ergen gold-bearing shear zone were mainly controlled by the tectonomagmatic event related to the regional sinistral ductile shear of the huge Irtysh(Ertix)strike-slip shear zone on the southern margin of the Siberian plate,and its tectonic setting is the post-collisional extensional environment of the Altay orogeny.更多还原