新疆昭苏卡拉盖雷铜金矿床成矿地质背景探讨

卡拉盖雷火山岩型热液铜金矿床位于新疆西天山那拉提构造带境内西段, 赋矿地层为下石炭统大哈拉军山组, 含矿岩石主要为玄武质凝灰岩、浅变质岩及隐爆角砾岩。矿体产于隐爆角砾岩筒及构造破碎带裂隙或片理、劈理微裂隙中。硅化、绿泥石化和电气石化是高品位矿石的蚀变标志。岩石地球化学研究表明, 区内大哈拉军山组火山岩以钙碱性系列为主, 含部分拉斑玄武岩系列, 富集LREE和大离子亲石元素(Rb、Ba、Th、K), 相对亏损HREE和高场强元素(Nb、Ta、Ti、P), 具有大陆火山弧亲缘性。综合伊犁—中天山板块南缘的构造演化特征, 认为矿区大哈拉军山组火山岩产于板块俯冲-碰撞后期较成熟的大陆火山弧环境。

Metallogenic Geological Background of the Kalagailei Copper-gold Deposit in Zhaosu County, Xinjiang

The Kalagailei volcanics-hosted hydrothermal copper-gold deposit is located in the western part of Nalati tectonic belt of Western Tianshan Mountains, Xinjiang. The ore-controlling strata are basaltic tuffs, epimetamorphic rocks and crypto-explosive breccia of Lower Carboniferous Dahalajunshan Formation. The copper ore bodies occur in crypto-explosive breccia pipes and fissures of the structural fracture zone, or in the micro-fractures of schistosity and cleavage. Silicification, chloritization, tourmalinization are the alteration indications of high-grade ores. Geochemical data show that volcanic rocks of Dahalajunshan Formation consist mainly of calc-alkaline series with partial tholeiite series, which are enriched in LREE and large-ion-lithophile elements (Rb, Ba, Th, K) and comparatively depleted in HREE and high field strength elements (Nb, Ta, Ti, P), possessing continental volcanic arc affinity. In combination with the tectonic evolution characteristics of the south margin of Yili-Central Tianshan plate, the authors consider that the Dahalajunshan Formation of the ore district occurred in a comparatively mature continental volcanic arc environment of plate subduction-collision in the later period.