鄂东南矿集区铁山铁矿床中磁铁矿元素

中国东部中生代经受由挤压向伸展的构造转换，为中酸性岩浆的运移和上侵提供了构造通道和空间，因此湖北东南部铁山铁矿床的成矿作用与燕山中晚期的中酸性岩浆侵入作用关系密切。许多学者对铁山铁矿床的矿床地质特征、成矿流体性质、控矿构造等问题进行了相应的研究，但对成矿物质来源、矿床成因、成矿流体温度、以及太平洋板块俯冲背景等的认识缺乏地球化学依据。本文在详细研究铁山铁矿床成矿地质背景和总结前人有关研究成果的基础上，通过电子探针和LA-ICP-MS原位分析，研究了该地区的磁铁矿元素的地球化学特征，认为铁山铁矿床主要存在镁矽卡岩型和岩浆—热液复合型两种矿床成因类型，其成矿物质主要来源于壳幔混溶型岩浆。这些研究为深入阐明鄂东南矿集区铁矿床成矿规律提供了新的地球化学依据。

Geochemical characteristics of magnetite elements in the Tieshan iron deposit in southeastern Hubei Province and geological implications

During Mesozoic, eastern China mainland experienced a transformation from compression to extension, which provided space and channels for migration of intermediate-acid magma. Therefore, metallogenesis of the Tieshan iron deposit in southeastern Hubei Province has close relationship with the intermediate-acid intrusion of the Middle-Late Yanshanian period in such a dynamic setting. Many researchers have studied geological characteristics, ore-forming fluid and ore-controlling structures of this iron deposit. However, their results on metallogenic material sources, genesis of the deposit, temperature of ore-forming fluid and the subduction model of the Pacific plate lack support of geochemical evidence. Based on detailed data of metallogenic geological background and previous work about petrological and geochemical evidence of the Tieshan iron deposit, this work performed in situ electron microprobe and LA-ICP-MS analysis of the magnetite elements in this area. The resultant geochemical characteristics of magnetite show that this iron deposit involves Mg-Skarn and magmatic-hydrothermal polygenetic genesis types. Its metallogenetic materials mainly emanated from mixed magma of crust and mantle. These insights provide new geochemical evidence for further elucidating the metallogenetic regularities of Fe-Cu deposits in southeastern Hubei Province.