阿尔金山脉中金雁山早古生代碰撞造山带:弧岩浆岩的确定与岩体锆石U-Pb和蛇绿混杂岩^(40)Ar/^(39)Ar年代学研究的证据

Jinyanshan collisional oroginic belt of the early Paleozoic in the Altun mountains:evidence from single zircon U-Pb and ^(40)Ar/^(39)Ar isotopic dating for the arc magmatite and ophiolitic mélange

岩石学和地球化学研究结果显示,出露在新疆阿尔金山北部红柳沟-拉配泉蛇绿混杂岩带南侧的金雁山花岗闪长岩体形成于安第斯型陆缘弧构造背景,测得岩体的单颗粒锆石 U-Pb 年龄为467.1±6Ma。此外,对红柳沟-拉配泉蛇绿混杂岩基质绢云母石英片岩中的绢云母进行的^(40)Ar/^(39)Ar 定年,获得坪年龄455±2Ma,等时年龄450±11Ma。上述结果证实,金雁山是一条形成在早古生代的碰撞造山带,其洋-陆俯冲造山作用可能发生在早-中奥陶世,陆-陆碰撞造山作用可能发生在中奥陶世末期。

It has been proved that the Jinyanshan granodiorite, which outcrops at the southern side of the Hongliugou-Lapeiquan ophiolitic mrlange zone in the northern part of the Altun Mountains, developed in the Andean-type arc tectonic setting by studied on its lithological and lithogeochemical features, and its formation age （467.1 ± 6Ma） has been gained by single zircon U-Pb isotopic dating of the granodiorite. In addition, we have also gained ^40Ar/^39Ar plateau age （455 ±2Ma） and isochrone ages （450 ± 11Ma） of sericite from sericite-quariz-schist within matrix in the Hongliugou-Lapeiquan ophiolitic melange zone. These results above indicate that Jinyanshan collisional orogenic belt developed during the early Paleozoic, and the ocean-continent subduction took mainly place during the early to middle Ordovician and the continent-continent collision occurred during end of the middle Ordovician.