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

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.