论文部分内容阅读
齐齐加纳克蛇绿混杂岩位于中国新疆西南天山阔克萨彦岭地区,主要由辉石橄榄岩,橄榄辉石岩,橄榄玄武岩,辉长岩,辉绿岩,基性熔岩等组成。它们以一系列构造碎片近东西向产出,断续沿长约5km,宽约500m。本文应用SHRIMP方法对该蛇绿混杂岩中玄武岩中的锆石进行SHRIMP锆石U-Pb测年,获得了399±4Ma的加权平均年龄,说明该蛇绿混杂岩形成于早泥盆世。结合前人的研究成果,我们推测齐齐加纳克蛇绿混杂岩与吉根蛇绿岩残片均为中亚造山带南天山蛇绿岩带的延伸,可能代表了一个多岛窄洋盆演化的产物,为南天山洋北向俯冲及其后的塔里木微板块与哈萨克斯坦-准噶尔板块陆陆碰撞形成的最后缝合带。
The Qiqiagenak ophiolitic mélange is located in the Khasakean Mountains in the Tianshan Mountains, southwestern Xinjiang, China and is composed mainly of pyroxenolite, olivine, olivine basalt, gabbro, diabase and basic lavas. They are produced in a series of structural fragments near east-west, intermittent along the length of about 5km, width of about 500m. In this paper, SHRIMP zircon U-Pb dating of SHRIMP zircons from the ophiolitic mélange was performed by SHRIMP method. The weighted average age of 399 ± 4Ma was obtained, indicating that the ophiolite mélange formed in the Early Devonian. Combined with the previous research results, we speculate that the Qiqi Ganek ophiolite mélange and the Jiage ophiolite felts are all extensions of the southern Tianshan ophiolite belt in the Central Asian orogenic belt and may represent a product of multi-island narrow oceanic basin evolution , Which is the last suture zone formed by the northward subduction of the South Tianshan Ocean and the subsequent continental collision between the Tarim microplate and the Kazakhstan-Junggar plate.