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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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References

Anand, R.R. and Gilkes, R.J. (1984) Weathering of ilmenite in a lateritic pallid zone. Clays and Clay Minerals, 32, 363374.CrossRefGoogle Scholar
Chernet, T. (1997) Mineralogical study on Australian sand ilmenite concentrate, Australia. Pp. 709712 in: Mineral Deposits (Papunen, H. editor). Balkema, A.A., Rotterdam, The Netherlands.Google Scholar
Clark, A.M. (1993) Hey's Mineral Index, Mineral Species, Varieties and Synonyms. Chapman & Hall, London, 848 pp.Google Scholar
Frost, M.T., Grey, I.E. Harrowfield, I.R. and Mason, K. (1983) The dependence of alumina and silica contents on the extent of alteration of weathered ilmenites from Western Australia. Mineralogical Magazine, 47, 201208.CrossRefGoogle Scholar
Grey, I.E. and Reid, A.F. (1975) The structure of pseudorutile and its role in the natural alteration of ilmenite. American Mineralogist, 60, 898906.Google Scholar
Grey, I.E., Li, C. and Watts, J.A. (1983) Hydrothermal synthesis of goethite-rutile intergrowth structures and their relationship to pseudorutile. American Mineralogist, 68, 981988.Google Scholar
Grey, I.E., Watts, J.A. and Bayliss, P. (1994) Mineralogical nomenclature: pseudorutile revalidated and neotype given. Mineralogical Magazine, 58, 597600.CrossRefGoogle Scholar
Lasserre, M., Yempier, P. and Soba, D. (1984) Pétrographie et géochronologie Rb/Sr des granites cambriens de Goutchhoumi et d’;Anloa (Cameroun). Bulletin de la Societé Géologique de France, 23, 511514.Google Scholar
Nickel, E.H. and Nichols, M.C. (1991) Mineral Reference Manual. Van Nostrand Reinhold, New York, 250 pp.CrossRefGoogle Scholar
Suresh Babu, D.S., Thomas, K.A., Das, P.N.M. and Damodaran, A.D. (1994) Alteration of ilmenite in the Manavalakurichi deposit, India. Clays and Clay Minerals, 42, 567571.CrossRefGoogle Scholar
Suzuki, K., Adachi, M. and Tanaka, T. (1991) Middle Precambrian provenance of Jurassic sandstone in the Mino Terrane, central Japan: Th-U-total Pb evidence from an electron microprobe monazite study. Sedimentary Geology, 75, 141147.CrossRefGoogle Scholar
Temple, A.K. (1966) Alteration of ilmenite. Economic Geology, 61, 695714.CrossRefGoogle Scholar
Tetsopgang, S., Suzuki, K. and Adachi, M. (1999) Preliminary CHIME dating of granites from the Nkambe area, northwestern Cameroon, Africa. Journal of Earth and Planetary Sciences Nagoya University, 46, 5770.Google Scholar
Teufer, G. and Temple, A.K. (1966) Pseudorutile - a new mineral intermediate between ilmenite and rutile in the natural alteration of ilmenite. Nature, 311, 179181.CrossRefGoogle Scholar