R1: Characterization and description of minerals

[R1P-13] Columbite group minerals from Mt. Nagatare, Fukuoka Prefecture

*Shin Ito¹, Seiichiro Uehara², Yohei Shirose³ (1. Itoshima HS, 2. Dept. Earth & Planet. Sci., Fac. Sci., Kyushu Univ., 3. Univ. Kyoto Univ.)

Keywords:Columbite group minerals, Mt. Nagatare

We searched on occurrence of columbite group minerals, that is known as signal of fractionation of pegmatite, by field survey at the Nagatare area. Their compositions are dominanted by Nb, Ta, Fe, and Mn. Ta/(Ta+Nb) and Mn/(Mn+Fe) values increase with fractionation. In pegmatites that is not enriched in Li, because of accompanied crystallization of garnet, there is greater increases in Ta/(Ta+Nb) over Mn/(Mn+Fe) of columbite group minerals. In Li pegmatite, there is greater increases in Mn/(Mn+Fe) over Ta/(Ta+Nb) with pegmatite evolution.