Abstract
Allanite [CaREEAl2FeSi3O12(OH)] is formed REE fluorocarbonates such as synchysite-(Ce) and bastnäsite-(Ce) [Ce(CO3)F] by hydrothermal alteration. Allanites from Ryoke granitoids are altered and these secondary minerals occur as vein, coat and pseudomorph of allanite. It is important to research the behavior of REE on hydrothermal alteration because REE in altered granitoids can be resource. However,there are many problems, containing hydroxyl and carbonate and contamination so, allanite and secondary minerals are not studied.In this study, chemical composition and relationship of allanite and secondary minerals. As a result, Ce2O3-La2O3 and Ce2O3-Nd2O3 ratios don't vary. This may show when REE fluorocarbonates are procuced, REE destribution depends on host mineral.
