Journal of the Mineralogical Society of Korea (한국광물학회지)
- Volume 2 Issue 1
- /
- Pages.8-10
- /
- 1989
- /
- 1225-309X(pISSN)
- /
- 2288-7172(eISSN)
Niobian Sphene from the McDonald Pegmatite Mine, Bancroft, Ontarion, Canada: Consideration of Substitutions
카나다 온타리오 밴크로프트의 맥도날도 페그마타이트 광산에서 산출된 Nb Sphene: 원소 치환에 관한 고찰
Abstract
Sphene from the McDonald pegmatite near Bancroft, Ontario, Canada was analyzed using EPMA. It contains 4.3 to 6.3 weight percent of Nb2O5 with an average formula Ca1.02(Ti0.62Al0.22Nb0.07Fe0.06Ta0.01)Si0.99(O4.85F0.16). Three types of subtitutions are possible; 1)2Ti4+=(Nb, Ta)5+ + (Al, Fe3+), 2) Ti + O = (Al, Fe3+) + (F, OH), and 3) 2Ti + O = Fe2+ + (Nb, Ta)5+ + (F, OH). T재 different schemes of substitutions for balancing the analysis are considered when the iron is either all ferric or all ferrous. Assuming stoichiometry fo Ca and Si, a general formula derived from the two different schemes is Ca(Ti0.64Al0.22Fe3+0.06-X {{{{Fe_{x}^{2+} }} Nb0.01)Sio4.80-XF0.16(OH)0.04+x.
Keywords