卤族元素在地球不同岩石和流体储库中具有显著的含量和元素比值差异，且易与金属元素结合形成络合物，是热液矿床中金属元素的重要搬运和富集形式，因而是研究成矿流体的来源和演化、成矿作用机制的重要手段。利用LA-ICPMS原位测定方柱石和热液矿物中流体包裹体的卤族元素是近年来国际上最新发展的分析技术，本项目拟以长江中下游成矿带典型的矽卡岩型铁矿床（铁山和金山店）和玢岩型铁矿床（陶村和梅山）为重点研究对象，在前人良好的工作基础上，查明矿床的热液蚀变、矿物组合和成矿期次，系统分析不同成矿阶段钠质蚀变矿物方柱石的结构、化学成分和卤族元素组成，配合热液蚀变矿物（石榴子石、透辉石和石英）的流体包裹体卤族元素和微量元素分析，准确限定两类矿床成矿流体来源、演化和成矿机制的异同，探讨膏岩层参与成矿的可能方式及具体作用，完善两类矿床的成因模式，推动我国卤族元素微区分析在矿床学中的应用。

Halogens have been known in a vaietry of rocks and geofluid resevoirs in the earth, and different reservoirs commonly have distinct halogen geochemistry signatures. Halogens can be easily complexed with metals, and play important roles on transport and deposition of metals. Therefore, Halogen geochemistry of ore-related fluids and minerals can provide key insights into fluid sources and evolution of ore-forming system. The most recent advance in halogen geochemistry is to analyze scapolite and fluid inclusions in situ using LA-ICPMS, which allows to reconstruct the evolution of ore-forming fluids. The proposed project focuses on the skarn-type iron deposits (Tieshan and Jinshandian) and iron oxide-apatite deposits (Taocun and Meishan)along the Middle and Lower Yangtze River metallogenic belt to tentatively make a better constraints on ore-forming processes using halogen geochemistry. Based on extensively previous studies on deposit geology, we will firstly examine alteration types, mineral assemblages, and paragenetic sequences of ore mineralization in details. Scapolite,formed at different ore-forming stages, will be selected to analyze their mineral textures, major and trace elements, and halogens in situ using LA-ICPMS. In combination with trace elements and halogens of fluid inclusions from different stages of hydrothermal minerals (garnet, diopisde, and quartz), the new dataset will allow us to examine the sources and evolution of ore-forming fluids for the two types of deposits,and the possible differences in ore-forming mechanism. Particularly, our new data can be used to examine the hot debate how evaporites were involved in the formation of iron deposits and their possible roles. The outcomes of proposed project will not only shed light on the better understanding of genetic models for the two types of mineral deposits, but also motivate microanalysis of halogen geochemistry on the application of hydrothermal deposits.