滇东南锡矿带锡石矿物学、矿物化学特征及锡矿成矿环境和成矿物质来源研究

The tin-ore belt of southeast Yunnan Province is the western part of Nangling Tungsten-Tin-ore belt which is the well-known metallogenic belt in the world. And there are hundreds of small and medium size tin-deposits and large-scale or super- large-scale tin polymetallic deposits such as Gejiu, Bainiuchang and Dulong. Tin mineralization is very extensive in this belt. However, there are also many different viewpoints on the metallogenic source, environment and genesis of these tin deposits. It has been shown that lacking of research data of the cassiterite mineralogy and mineral chemistry may be one reason to support the disputed viewpoints. Actually, there is almost no any research output about cassiterite mineralogy and mineral chemistry in the belt. But the existed researches have shown that the characteristics of cassiterite mineralogy and mineral chemistry can reveal the environment, source and mechanism of cassiterite or large-scale tin mineraliazation effectively. So, it is very essential to conduct a project to study the cassiterite mineralogy and mineral chemistry for explaining the source and environment of large-scale tin mineralization in the tin-ore belt of southeast Yunnan Province. In the project, the cassiterite mineralogy and mineral chemistry such as occurrence, shape, color, internal structure, lattice parameters, main element, micro-element, REE, fluid inclusion, and C, H, O isotope of cassiterite will be obtained based on the systematically modern mineral analysises of scanning electron microscope, cathode luminescence imaging technique, X powder crystal diffraction analysis, electronic probe X-ray micro-zone analysis, LA-ICP-MS and laser Raman. Combining the characteristics of cassiterite mineralogy, mineral chemistry, U-Pb geochronology and the characteristics of the deposits and regional metallogenic background, we can disscuss the environment, source, and mechanism of cassiterite of the tin-ore belt of southeast Yunnan Province deeply. And it will be of great significances to guide the deposit genesis model establishing and tin ore prospecting.

滇东南锡矿带发育个旧锡多金属矿、白牛厂银锡多金属矿、都龙锡矿等大型、超大型矿床。而有关这些锡矿床的成矿环境、成矿物质来源和矿床成因还存在争议，其原因之一是矿带内典型锡矿床的锡石矿物学、矿物化学特征研究还较为薄弱。直接利用锡矿床的矿石矿物锡石开展锡石矿物学、矿物化学研究，可以有效地揭示锡矿的成矿环境、物质来源和矿床成因。本申请拟选择矿带内白牛厂、都龙两典型矿床的锡石为研究对象，运用扫描电镜、CL成像、X 粉晶衍射、电子探针微区原位分析、LA-ICP-MS微区原位分析、激光拉曼等先进技术研究矿带内锡石的形态、颜色、内部结构、晶胞参数、主微量元素、稀土元素、流体包裹体和C、H、O同位素等矿物学和矿物化学特征，总结出各矿床的普遍特征和独有特色，进而结合矿带内典型矿床的成矿背景、地质特征和成矿年代，探讨矿带内锡矿的成矿环境和成矿物质来源，建立矿床成因模式。为完善矿带内矿床成因模型和指导找矿提供依据。

项目运用扫描电镜、CL成像、X 粉晶衍射、电子探针微区原位分析、LA-ICP-MS微区原位分析、激光拉曼、mapping等先进分析技术针对滇东南锡矿带典型矿床的锡石矿物学、矿物化学和锡矿成矿环境、成矿物质来源开展了深入系统的研究，按计划完成了研究任务，取得了丰富的成果并获得如下认识：（1）滇东南锡多金属矿床中锡石样品的U-Pb定年结果为82-86Ma，和区域内花岗岩类的侵位年龄一致，这暗示了该矿床为岩浆-热液成因。（2）锡石颗粒中Nb、Ta、Zr和Hf与震荡环带的分布相关；CL中的暗色区域具有高的Fe，Ga，Sb，W和U含量；含锡花岗岩中的锡石比其它类型矿石中的锡石具有更高的Nb和Ta含量。（3）锡石颗粒中微量元素如W，U，Fe，Sb，Sc，V，Fe和Ga的分布揭示了只有含锡石的花岗岩形成于氧化环境，而其它锡石则主要形成在还原环境。（4）过铝质含锡花岗质岩石是由准铝质非锡熔体经历岩浆分异和流体析出过程形成的。（5）研究揭示并非所有富锡的过铝质花岗岩都来自于变质沉积岩石熔融过程，它们也有可能是由准铝质熔体演化而来。项目理清了滇东南锡矿带个旧、白牛厂和都龙锡矿等典型矿床的锡石矿物学、矿物化学特征，积累了一批科学数据；总结出了滇东南锡矿带各典型矿床间的共性普遍规律和独有特征，揭示出了矿带内典型锡矿床的成矿环境和成矿物质来源，建立了切合实际的矿床成因模式。研究成果为深入认识滇东南锡矿带的矿床成因和矿产勘查提供了科学依据。项目最终提交交结题报告 1 份，发表国际SCI 论文 8 篇，培养硕士研究生3人，博士后3人，项目研究人员晋升副教授3人，获得云南省教学名师1人，获得云南省优青1人，获得东陆青年骨干教师1人，获得云南省万人（千人）计划高层次人才3人,新增云南省教育厅科技创新团队1个。