【摘要】 在阿尔泰南缘的多摩拉克布拉克地区,新发现含石榴子石和白云母的淡色花岗岩侵入于早石炭世南明水组火山沉积地层中。LA-ICP-MS锆石U-Pb测年结果表明,淡色花岗岩形成于311±3 Ma的晚石炭世早期。该淡色花岗岩的发现及其年龄的确定,结合区域岩浆岩、变质岩和沉积学等资料分析,表明阿尔泰造山带南缘在~311 Ma前完成碰撞过程,并从此进入后碰撞时代。该发现为进一步研究阿尔泰造山带晚古生代构造演化提供了新的证据。更多还原

【Abstract】 The time frame for the collision between Siberia Plate and Kazakhstan-Junggar Plate and the initiation of post-collision of the Southern Altay Range in the Late Paleozoic remain controversial. Paleozoic granitoid magmatism played an important role in the tectonic evolution of the Southern Altay Range and various origins of granitoids have been found in this region, including I-, S-, A- and M-type granitoids. Here, we report the newly discovered Duomolakebulake garnet- and muscovite- bearing leucogranite which intruded the Early Carboniferous Nanmingshui volcanic-sedimentary formation in the southern Altay Range. LA-ICP-MS zircon U-Pb dating indicates that the leucogranite was generated in the early Late Carboniferous(311±3 Ma). As an important rock type for tectonic implications, leucogranite is considered to be generated in a post-collision setting. In combination with lithology data in this region, we suggest that the collision ended prior to ~311 Ma in the southern Altay Range, and then evolved into the post-collisional stage. This new discovery may shed lights on the tectonic evolution of the Altay Range in the Late Paleozoic.更多还原