西澳大利亚伊尔岗克拉通铁矿床研究进展  

The progress in the study of the iron ore deposits in Yilgarn Craton,Western Australia

作　　者：韩宁[1] 江思宏[1] 白大明[1] 陈春良[1] 刘源[1] 

机构地区：[1]中国地质科学院矿产资源研究所/国土资源部成矿作用与资源评价重点实验室,北京100037

出　　处：《地质通报》2015年第6期1086-1099,共14页Geological Bulletin of China

基　　金：地质大调查项目(编号:1212011120325)

摘　　要：伊尔岗克拉通位于澳大利亚西南部,是地球上最古老的克拉通之一。该克拉通内产出的铁矿床均与条带状含铁建造(BIF)有关,可分为2种类型:1深成—表生矿床;2表生—富集矿床,主要分布在尤恩米(Youanmi)地体中。深成—表生型铁矿床具有相似的变形历史、镁铁质火成岩围岩、深成热液蚀变事件和高品位的铁矿石类型。深成热液蚀变包括早期碳酸盐-磁铁矿蚀变、中期形成磁铁矿矿石、晚期碳酸盐-赤铁矿蚀变,但是这些矿床在岩相、变质程度、矿物学和地球化学方面都存在差异,目前还没有统一的成因模型。表生—富集型铁矿床可能是通过表生淋滤BIF中的硅质条带形成的,但不含硅质条带的BIF的出现,说明没有对硅质条带的选择性表生溶解也可以形成高品位矿体。The Yilgarn Craton located in the southwest of Australia, is one of the oldest cratons in the world. The iron ore deposits occurring within the Yilgarn Craton are associated with BIF sequences, which is common in the Youanmi Terrane of the craton.Two types of iron ore deposits have been recognized：（1）hypogene-supergene iron ore deposits;（2）supergene-enrichment iron ore deposits. The hypogene-supergene iron deposits share comparable deformation histories, mafic igneous host rocks, hypogene alteration events and styles of high-grade iron ore. A common hypogene alteration sequence comprising early carbonate–magnetite alteration followed by intermediate magnetite ore formation and late carbonate-hematite alteration has been established. However, this kind of deposits have different stratigraphic facies, metamorphic grades, and mineralogical as well as chemical characteristics, therefore a unified model has not been established yet. The supergene-enrichment iron ore deposits were formed by the supergene leaching of the chert bands from BIF, nevertheless, the occurrence of chert-free BIF demonstrates that high-grade ore could have been formed without the selective supergene dissolution of the chert bands.

关 键 词：条带状含铁建造(BIF) 矿床成因 深成—表生矿床 表生—富集矿床 伊尔岗克拉通 西澳大利亚 

分 类 号：P618.31[天文地球—矿床学]