摘要我国铁矿资源多，品位较低，富铁矿成为我国经济发展的急缺矿产之一。
位于辽宁省鞍山—本溪地区的弓长岭富铁矿是我国重要的富铁矿床，它以矿石储量大，品位高，易选冶为闻名。
本文在系统收集、整理弓长岭铁矿已有地质资料的基础上，进行野外实地踏勘，室内分析，总结该区成矿地质背景基础上，重点研究弓长岭富铁矿区地质特征、BIF型富铁矿床含铁岩系、矿体分布和矿石类型进行分析，明确了富矿形成机制，并得出以下认识：In our country, iron ore resources are very rich, but ore content are lean. Iron ore with rich grade becomes one of the urgent shortages of mineral in the development of economic. Gongchangling rich iron ore located in Liaoning Province Anshan-Benxi area plays an important role in the rich iron ore mining, which is famous for abundant reserves, high grade and easy for beneficiation and metallurgy. Based on collecting and organizing systematically geological data of Gongchangling, the field reconnaissance and laboratory analysis also have been carried out. Summing up the metallogenic geological background and focusing on the research of Gongchangling iron rich geological features, BIF iron rich deposits containing iron rock department, distribution of ore bodies and ore types are armed at analyzing rich-grade iron ore formation mechanism. Some conclusions are drawn as follows:（1）一、三矿区含铁岩系为同一套含铁岩系，其大致与二矿区K层到上含铁带相当，一、三矿区Fe1、Fe2两矿层相对于二矿区Fe4、Fe6，通过地球化学特征对比得出三个铁矿床原始沉积环境一致。
弓长岭铁矿中二矿区含铁岩系出露最全，可以作为弓长岭铁矿的标准含铁岩系剖面。
(1) The ferruginous rocks are same in Ⅰ#andⅢ#, which are as same as that from K layer to up mineral belt in Ⅱ#approximately. Original sedimentary environment of iron deposits between Fe1 and Fe2 layers of Ⅰ# and Ⅲ# and Fe4 and Fe6 of Ⅱ# are consistent by the comparison on the geochemical characteristics of that three iron deposits. The ferruginous rocks of Ⅱ#outcrop mostly in Gongchangling Iron Mine, which can be used as the standard of ferruginous rocks section.（2）磁铁富矿主要分布在第六层铁矿之中，其次在第五层、第四层、第三层、第二层及硅质层中也有分布。
地表较少，深部较多。
东南区较少，中央区和西北区较多。
磁铁富矿：呈黑色，致密块状，呈细粒或粗粒结构。
磁铁富矿中主要金属矿物有磁铁矿，偶尔有赤铁矿。
磁铁富矿的围岩主要是绿泥片岩、石榴绿泥片岩、绿泥石榴岩和少量黑云母绿泥片岩，组成的组要矿物为绿泥石、石榴石和少量黑云母，且它们是副变质成因。
磁铁富矿体主要受褶皱和断层的控制，富铁矿体主要赋存于褶皱核部和断层中。
磁铁富矿是由磁铁石英岩形成的，富铁矿体产于磁铁石英岩旁边和磁铁石英岩里，具有相似的矿物组份和地球化学特征。
(2) Magnetite rich ore are mainly distributed in the sixth floor of iron ore, and then in the fifth layer, the fourth layer, the third layer, the second layer and silicon layer can also be found. Less surface, more deep. The southeast region is less, more central and northwest region. Magnetite rich: black, massive, fine-grained or coarse-grained structure. The main metal mineral magnetite rich in magnetite, hematite occasionally. Magnetite rich ore rock is mainly chlorite schist, garnet chlorite schist, chlorite pomegranate rocks and minor biotite chlorite schist, group composition to mineral chlorite, garnet and minor biotite, and they are pair of metamorphic origin. The rich ore body is controlled by the folds and faults, and the rich iron ore body mainly occurs in the fold core and the fault.. Magnetite rich ore is formed by magnetite quartzite, rich iron ore produced in magnetite quartzite and beside the magnetite quartzite, with similar mineral components and geochemical characteristics.（3）铁矿体产于由斜长角闪岩、黑云母变粒岩、磁铁石英岩和蚀变岩组成的含铁岩系中。
本区绿泥石、石榴石和黑云母的铁含量与铁矿石品位关系十分密切。
总体来说，越是靠近磁铁富矿，其对应的铁含量就越高，反之，远离富铁矿，铁含量降低。
通过分析对比可知该区蚀变岩原岩是泥质-粉砂岩，且从常量元素、微量与稀土元素分析结果看，其形成过程与磁铁富矿体形成过程有密切关系，同时结合富铁矿与磁铁石英岩的关系可知磁铁富矿的成因与变质热液关系密切。
(3) Iron ore body produced by amphibolite, biotite granulite, magnetite quartzite and altered rocks composed of iron bearing rock series. The relationship between iron content and iron ore grade in the area of chlorite, garnet and biotite are very close. In general, the more close to the magnetite rich ore, which corresponds to the ironcontent is higher, conversely, away from the rich iron ore, iron content reduced. Through analysis comparison shows that the alteration of the protolith of argillaceous siltstone, and from the constant element, trace element and REE analysis results show. The formation process and the rich iron ore forming processes are closely related, combined with rich hematite and magnetite quartzite relationship show Ci Tiefu ore genesis and metamorphic hydrothermal close relationship.（4）区域变质作用为磁铁富矿的形成提供了变质热液、储矿空间、变质热液运移动力、矿物转换提供所需的温压条件，变质热液可以淋滤磁铁石英岩中的FeO，区域变质作用是磁铁富铁矿形成的重要条件。
(4) Regional metamorphism magnetite rich ore formation provides the metamorphic hydrothermal fluid, ore storage space, metamorphic hydrothermal migration force, mineral transformations provide the required temperature and pressure conditions, metamorphic hydrothermal fluid can leaching magnetite quartzite of FeO and regional metamorphism is important role for the rich iron ore forming.（5）弓长岭二矿区含有多层磁铁石英岩，其间夹有泥质-粉砂质沉积物，导致受力变形以及SiO2吸收两方面都相对于单一厚大磁铁石英岩有利，所以二矿区更易形成磁铁富矿体。