U.S.-China Cooperative Research (Geol.): Geochemical Studiesof the Massive Sulfide Gold Deposits of the Tongling District, Anhui, China

中国冶金工业部东中国地质勘探公司林根范、万鑫博士与弗吉尼亚理工学院和州立大学的James R.Craig博士和Robert J.Bodnar博士共同提出的“安徽省铜陵区块状硫化物金矿床的地球化学研究中国”是由美国国家自然科学基金会和中国冶金工业部联合发起的。这项联合研究旨在对安徽省铜陵地区中东部中国地区一个重要但鲜为人知的成矿省的矿床进行详细的地质调查。该地区拥有大量矽卡岩型和层控块状硫化物矿床，其中含有可开采或潜在可开采数量的基本金属和黄金，特别是铜金矽卡岩型矿床、层控铜金矿和铁帽金矿。调查人员试图确定这些矿床形成的条件，并确定这两种不同的矿床类型是否在成因上有关联。为了实现这一目标，对矿石和脉石矿物进行详细的岩相学和电子探针分析将确定矿床内的矿物学和矿物化学，并寻求建立一个全面的共生序列。同时，详细的流体注入研究，包括标准的显微测温和激光拉曼分析，将确定成矿流体的组成和物理状态。这种对明显不同地质背景和表观成因的金矿床的研究，为发现金的地球化学迁移和沉积提供了一个新的方面。具体地说，通过探索明显与火成岩活动有关的矿床(如夕卡岩)与完全赋存于沉积物中的矿床(层控矿床)和空间上与侵入体无关的矿床之间的关系，对这些矿床的研究可能提供有关含金热液系统演化的宝贵信息。这项研究有望对金矿成因有新的认识，可能会导致新的勘探战略和技术在美国和中国都有用。

This proposal on "Geochemical Studies of the Massive Sulfide Gold Deposits of the Tongling District, Anhui Province, China," between Drs. James R. Craig and Robert J. Bodnar of the Virginia Polytechnic Institute and State University and Messrs. LIN Gen Fan and WAN Xin of the East China Geological Exploration Company of the Chinese Ministry of Metallurgical Industry (MMI), is jointly sponsored by NSF and by the Chinese MMI. This joint research aims at a detailed geological investigation into the ore deposits of a major, but little known, metallogenic province in east central China, the Tongling area of Anhui province. This area contains a large number of skarn and stratabound massive sulfide deposits that contain mineable or potentially mineable quantities of base metals and gold, specifically copper gold skarn deposits, stratabound copper gold deposits, and gossan gold deposits. The investigators seek to define the conditions under which these deposits formed and to determine if the two different deposit types are genetically related. To achieve this, detailed petrographic and electron microprobe analyses of ore and gangue minerals will define the mineralogy and mineral chemistry within the deposits and seek to establish a comprehensive paragenetic sequence. At the same time, detailed fluid infusion studies, including standard microthermometry and laser Raman analyses, will define the composition and physical state of the mineralizing fluids. This study of gold deposits in distinctly different geological settings and apparent genesis provides an opportunity to discover new aspects of the geochemical transport and deposition of gold. Specifically, study of these ore deposits may provide valuable information about the evolution of gold bearing hydrothermal systems, by exploring the relationship between deposits that are clearly related to igneous activity, such as the skarns, and those that are hosted entirely in sediments (the stratabound deposits) and spatially unrelated to an intrusive body. The new insight into gold ore genesis promised by this research could lead to new exploration strategies and techniques useful both in the United States and in China.