2007 年 57 巻 2 号 p. 115-125
Chemical characteristics of apatites from S-type and I-type granites, and some igneous apatite deposits are reviewed. REE compositions of the apatites in granites are much dependent upon original composition of the granitic rocks, oxidation-redox state and fractionation degree of the granitic magmas. Highly phosphorous melts are necessary to concentrate in the El Laco-type magnetite deposits. Together with the conventionally known apatite deposits associated with some carbonatites and ultra-alkaline plutonic rocks, these rock-and-ore apatites need to be re-evaluated as a source for REE, including extraction technology.