华北克拉通南缘分布的BIFs矿床由于露头不理想长期缺乏系统全面的研究。本申请拟选择其中三个代表性的矿床，霍邱，新蔡和舞阳BIFs矿床，围绕它们的成矿作用及成矿古环境开展系统全面的研究。前期调研发现，它们在很多方面具有相似性，如成矿时代，地球化学特征及成矿物质来源等。因此，有必要利用新方法对它们开展对比研究，揭示它们之间是否存在内在成因联系。作为氧化还原状态变化的指示剂，保存于BIFs中的铁和铬同位素，记录了古海洋和古大气的环境演化特征。本申请拟采用传统研究方法，结合铁和铬同位素研究成果，对上述矿床开展系统比较研究，结果将揭示它们的成矿机制及成矿时的古海洋和古大气环境特征，也将为它们是否存在内在成因联系提供进一步的证据，同时，为在华北克拉通南缘寻找类似的铁矿提供坚实的理论支持。

Since the relatively small size of iron ore, and the undesirable outcrop, the BIFs deposits in the southern margin of the North China Craton always lacks systematic and comprehensive study for a long time. This application intends to choose three representative deposits, Huoqiu, Xincai and Wuyang BIFs deposits, revolve round their metallogenesis and implications for paleoenvironmental evolution, and carry out this research systematically and comprehensively. The proposer previous investigated and found that they are similar in many aspect, such as the REY characteristics of BIFs and the source of metallogenic material. Therefore, it is necessary to use the new methods to carry out comparative studies on them and to reveal the internal genetic links between them. Fractionation of iron and chromium isotopes preserved in BIFs, as the solid proxy of redox state changes, record the redox state and chemical composition characteristics of ancient oceans and paleo atmosphere. If find they are formed under similar metallogenic paleo ocean and paleo atmospheric environment by contrastive study, which will provide further evidence for their internal genetic links, while also further define the metallogenic mechanism of BIFs, furthermore provide solid theoretical support in searching similar deposits at the southern margin of the North China Craton.