小秦岭桐沟大型石英脉型金矿床成矿过程：来自白钨矿和独居石原位微区分析的精细制约

石英脉型金矿床由于成矿流体在长距离的迁移过程中会卷入不同来源的物质，且矿体常为多期次/阶段热液活动产物，因而对其成矿过程的精细刻画一直是国际矿床学界研究的难点。华北克拉通南缘的小秦岭金矿田是全球石英脉型金矿床最为集中的地区之一，其成矿过程十分复杂，成矿机制认识仍存在很大分歧。区内桐沟大型金矿床中白钨矿和独居石的生长贯穿了主要成矿阶段，环带结构发育，直接记录了成矿过程中的重要信息。因此，本项目拟以白钨矿和独居石矿物自身特性为切入点，开展精细的矿物原位微区分析研究。依据白钨矿结构、微量元素及Sr同位素特征，结合独居石U-Pb同位素定年，揭示成矿物理化学条件、矿质迁移-沉淀过程、成矿流体来源及成矿时代，在微观尺度上精细刻画桐沟金矿床成矿过程。旨在通过典型矿床的研究为小秦岭石英脉型金矿床成矿机制提供精细可靠的新证据。

Since the fact that the other materials from various depths at different locations will be involved in or mixed with the ore-forming fluids along the long migrant pathways, and the auriferous quartz veins were commonly deposited during multi-stage hydrothermal activities, it has long been a sticking point to precisely constrain the ore-forming process of lode gold deposits in the metallogeny research worldwide. The Xiaoqinling goldfield, located along the southern margin of the North China craton, is one of the most concentrated areas of lode gold deposits in the world. Due to the complex hydrothermal processes, the ore genesis remains controversy so far. At the Tonggou large lode gold deposit in this area, scheelite and monazite with zoning structure occurred through the major mineralization stages, which directly recorded the important information of the metallogenic process. In the light of the scheelite micro-structure, in-situ trace element compositions and Sr isotope characteristics, combined with in-situ U-Pb isotope dating of monazite, this project intends to reveal the physico-chemical conditions of mineralization, elements migration precipitation, origin of ore-forming fluid and age of gold deposition, and precisely depict the metallogenic process of the Tonggou gold deposit on the micro-scale. The study of typical lode gold deposit is expected to provide new robust evidence for the metallogenic mechanism of the Xiaoqinling lode gold system.