东天山造山带中斑岩铜矿金属富集和成矿机制：以新疆土屋铜矿为例

斑岩铜矿床的形成与成矿岩浆熔体和成矿流体的组成及演化密切相关。矿物和熔/流体包裹体微区原位成分分析是研究岩浆-流体演化、探讨铜金属富集和成矿机制的重要手段。新疆东天山大南湖-头苏泉岛弧带南缘近东西向直径距离40公里范围内发育5个重要斑岩铜矿床，展示出良好的铜成矿潜力与找矿前景，然而关于铜金属富集、成矿机制，目前尚缺乏深入研究。本项目拟以土屋铜矿床为主要研究对象，结合对比东天山岛弧带邻区斑岩铜矿床，运用成矿系统理论，借助电子探针和微区原位分析技术，查明东天山造山带中斑岩铜矿热液脉体、蚀变与矿化时空结构，厘定初始流体出溶、熔/流体演化以及矿质沉淀等过程中温度、压力、成分、同位素等变化规律，阐明矿床形成中成矿流体产生、迁移以及成矿物质沉淀富集过程，揭示Cu金属富集和成矿机制。本项目对于丰富斑岩铜矿成矿理论，深入认识控制东天山斑岩矿床铜成矿作用的关键因素，指导研究区斑岩铜矿找矿工作都具有实际意义。

The formation of porphyry copper systems is closely associated with composition and evolution of ore-related magmas and exsolved fluids from melts. In-situ microanalyses on minerals and melt or fluid inclusions can provide effective methods to determine magmatic-hydrothermal evolution, metal enrichment and mineralization mechanism. Five significant porphyry Cu deposits have been discovered along the southern margin of Dananhu-Tousuquan Arc in Eastern Tianshan, Xinjiang, implying economic copper mineralization potential and prospect, but their metallogenic mechanism is still not very clear. In this proposal, the Tuwu Cu deposit has been selected for electron probe and in-situ microanalyses, with comparison of several other porphyry deposits in Eastern Tianshan. Based on regional metallogenic theory, as well as detailed observations on hydrothermal vein, alteration and mineralization at Tuwu, we will investigate the changes of temperature, pressure, composition and isotopes through time during magma evolution, fluid exsolution and evolution, and metal deposition processes. These observations and results would reveal the metal enrichment and mineralization mechanism in the evolving magmatic-hydrothermal system at Tuwu. This study will also be helpful in understanding the major factor controlling the formation of porphyry Cu deposits in Eastern Tianshan and elsewhere, and beneficial to copper exploration in the region.