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Hydroxylian pseudorutile in an adamellite from the Nkambe area, Cameroon

Published online by Cambridge University Press:  05 July 2018

S. Tetsopgang
Affiliation:
Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8602, Japan
J. Koyanagi
Affiliation:
Department of Earth Sciences, Kanazawa University, Kanazawa 920-1192, Japan
M. Enami*
Affiliation:
Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464-8602, Japan
K. Kihara
Affiliation:
Department of Earth Sciences, Kanazawa University, Kanazawa 920-1192, Japan

Abstract

Hydroxylian pseudorutile in an adamellite from Cameroon has been identified using EPMA, FT-IR and single-crystal XRD analysis. TiO2 and Fe2O3 contents range between 60.6 and 67.9 wt.% and 22.2 and 36.5 wt.%, respectively, and totals vary from 90.1 to 98.1 wt.%. The SiO2 (0.03 —1.40 wt.%), Al2O3 (0.02—0.68 wt.%) and CaO (0.03—0.44 wt.%) contents increase systematically and MnO (0.04—0.69 wt.%) decreases slightly with decreasing Fe3+/Ti values. The MgO content is <0.06 wt.%. H2O contents (1.3—7.5 wt.%) are greater in parts of crystals with lower Fe3+/Ti, suggesting solid solution between the end-members Fe3+2Ti3O9 and Fe3+Ti3O6(OH)3. The lattice parameters are a = 2.85 Å and c = 4.57 Å with hexagonal symmetry and point group 6/mmm.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2003

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