新疆卡特巴阿苏金铜矿床地质特征及构造环境

Geological Characteristics and Tectonic Setting of the Katbasu Au- Cu Deposit in Xinjiang

新疆卡特巴阿苏金铜矿床位于新疆西天山那拉提构造带的北缘,主要赋存于晚泥盆世二长花岗岩之中。推测富矿二长花岗岩形成于俯冲-碰撞-造山的构造环境,可能是以下动力过程的产物:伊犁中天山南缘地壳解体,地幔物质强烈加入形成的新生南天山洋壳,向北沿那拉提构造带俯冲,部分熔融后在碰撞-造山晚期于晚泥盆世侵入,且与海西运动早期的地质事件关系密切。成矿年龄推测为二叠纪,与成岩年龄相差约91Ma,所以成矿物质应该不是来源于二长花岗岩。从成矿构造与矿体关系及矿石结构构造特征来看该矿受到断裂和节理裂隙系统的联合控制,且在成矿期经历了一次先挤后张的地质构造事件。结合区域构造演化,推测此次地质构造事件应该与二叠纪塔里木地台北缘一带发生的裂谷引张作用有关。

The Katbasu gold-copper deposit of Xinjiang,located the north margin of the Nalati tectonic belt in western Tianshan, mainly occurred in the late Devonian monzogranite.This ore-rich rock probably formed in a tectonic setting of subduction-collision-orogen, as the product of the following dy- namic processes ： crust of southern margin in central Tianshan at Yili broke up, mantle material strongly joined the newly formed oceanic crust of south Tianshan which was subducted northward beneath the Nalati tectonic belt and invaded after partial melting during collision-orogeny in late Devonian, which has a close relationship with geological events of Hercynian movement.The age of metallogenic is presumably Permian, which is about 91 Ma later than the age of monzogranite, so metallogenic minerals did not stem from the monzogranite.From the relationship between metallogenic structure and ore bodies and the textural characteristics, this deposit was controlled by both faults and joint fissure systems, and experienced a process of compression to tension.In combination with regional tectonic evolution, we speculate that this tectonic event should be related to the rift extensions of the northern margin of Tarim plat- form during Permian time.