Kiruna-type or IOA deposits are characterized by magnetite-apatite-actinolite associations and may contain considerable amounts of rare earth elements (REEs) that can be exploited as by-products. REEs in the Kiruna-type deposit, heterogeneously distributed, are mainly hosted in phosphates (e.g. apatite). Published data of apatite, together with other evidence, can be used to decipher the source, enrichment mechanism, and post-ore modification of REEs in the Kiruna-type deposits. Sr isotopes and melt inclusions compositions of apatite, together with...