[S-RD33] 資源地質学

[SRD33-P14] 花崗岩中の希土類含有鉱物の量比とイオン吸着型鉱化作用との関係：ブラジル連邦共和国Serra Verde鉱床の例

*実松 健造¹、昆 慶明¹、横山 隆臣¹ (1.国立研究開発法人　産業技術総合研究所　地圏資源環境研究部門)

キーワード：花崗岩、希土類、鉱床、イオン吸着型、Serra Verde、ブラジル

The Serra Verde REE (rare earth elements) deposit located in Goiás and Tocantins provinces of Brazil is one of ion-adsorption type deposits found outside of China. The REE ores are weathered granitic rocks and sediments underlain by the Serra Dourada Granite consisting of alkali granite and gneissic granite. The granites are high in REE (300 – 1300 ppm, approximately) and contains different REE-bearing minerals such as bastnaesite-(Ce), allanite-(Ce), monazite-(Ce), xenotime-(Y), apatite and zircon. In this study, we report abundances of REE-bearing minerals in the granites and relationship with ion-adsorption type ore formation because a percentage of ion-exchangeable REE in the ores is influenced by assemblage of REE-bearing minerals in the parent granitic rocks.