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Mboziite, a new sodic amphibole end-member

Published online by Cambridge University Press:  14 March 2018

P. W. G. Brock
Affiliation:
Dept. of Geology, University of Leeds, Leeds 2
D. C. Gellatly
Affiliation:
Dept. of Geology, University of Leeds, Leeds 2
O. von Knoebing
Affiliation:
Dept. of Geology, University of Leeds, Leeds 2

Summary

An amphibole occurring in the Mbozi syenite–gabbro complex in SW. Tanganyika approaches very closely to the theoretical end-member Na2Ca;it has α 1·705, pale to light yellow, β 1·713, deep blue-green, γ 1·715, deep blue to green to black, with γ ∥ [010] and β : [001] about 7 to 14°; absorption γ > βα, with the maximum absorption on (010) at 9 to 12° to [001]. The mineral shows anomalous bright orange-red interference colours and incomplete extinction in sections parallel to (010) even in monochromatic light. X-ray powder data are given. A very similar amphibole occurs in the Darkainle nepheline-syenite complex, Borama district, Somali Republic.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1964

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References

Borley, (G.D.), 1963. Min. Mag., Vol. 33, p. 358.Google Scholar
Brock, (P. W. G.), 1961. A Brief Summary of The Geology of The Mbozi Syenite- Gabbro Complex, Tanganyika. Fifth ann. rep. Res. Inst. of Afr. GeoL, Leeds Univ., p. 35.Google Scholar
Brock, (P. W. G.) 1963. The Mbozi Syenite-Gabbro Complex, S.W. Tanganyika. Ph.D. Thesis, Geology Dept., Univ. of Leeds.Google Scholar
Eskola, (P.) and Sahlstein, (T.G.), 1930. Extrait Compt. Kend. Soc. Geol. Finlande, no. 3, p. 13.Google Scholar
Frost, (M.T.), 1963. Min. Mag., vol. 33, p. 377.Google Scholar
Garson, (M.S.), 1961. The Tundulu Carbonatite Ring-Complex in Southern Nyasaland. Ph.D. Thesis, Geology Dept., Univ. of Leeds.Google Scholar
Gellatly, (D. C), in preparation. The geology of the Darkainle Nepheline Syenite Complex, Borama District, Somali Republic. Ph.D. Thesis, Geology Dept., Univ. of Leeds.Google Scholar
Miyashiko, (A.), 1957. Journ. Fac. Sci., Univ. Tokyo, sec. 2, vol. 11, pt. 1, p. 57.Google Scholar
Newton, (A.R.) and Drysdaix, (A.R.), 1960. Rec. Geol. Surv. Northern Rhodesia for 1959, p. 26.Google Scholar
Sahama, (T.G.), 1956. Amer. Min., vol. 41, p. 509.Google Scholar
Shoda, (T.), 1954. Min. Journ. (Min. Soc. Japan), vol. 1, p. 69.Google Scholar
Sundiits, (N.), 1946. Sver. Geol. Unders., ser. C, no. 480 (Arsbok 40), p. 1.Google Scholar