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Pyroxenes from the gabbros of the Marangudzi ring complex, Rhodesia

Published online by Cambridge University Press:  05 July 2018

M. T. Hossain*
Affiliation:
Department of Geology, University of Nigeria, Nsukka, Nigeria

Summary

Chemical, X-ray, and optical analyses of eight Ca-rich pyroxenes and three coexisting Ca-poor pyroxenes from the gabbros of the Marangudzi ring complex, Rhodesia, are presented. Both the series show limited Fe-enrichment. High Ca-content of the clinopyroxenes together with their restricted Fe-enrichment, having a trend from Ca44·8Mg42·6Fe12·6to Ca42·7Mg37·7Fe19·6, could be indicative of an alkaline nature. But the presence of a Ca-poor pyroxene phase with a compositional trend between Ca2·9Mg71·2Fe25·9 and Ca3·1Mg63·0 Fe34·9 onwards in small amounts suggests tholeiitic to calc-alkaline nature. Certain characteristics in the variation in composition of the pyroxenes confirm a transitional nature of the Marangudzi parent magma, originating at a depth comparatively greater than the normal tholeiitic magma, but less deep than alkaline magma, at a fairly high pressure. The Marangudzi pyroxenes are compared with the pyroxenes of the similar world-wide igneous complexes.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1977

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References

Aoki, (K.), 1964. Am. Mineral. 49, 1199–223.Google Scholar
Atkins, (F. B.), 1969. J. Petrol. 10, 222–45.CrossRefGoogle Scholar
Bartholome, (P.), 1961. Geol. Mag. 98, 346–8.CrossRefGoogle Scholar
Best, (M. G.) and Mercy, (E. L. P.), 1967. Am. Mineral. 52, 436.Google Scholar
Brown, (G. M.), 1957. Mineral. Mag. 31, 511–43.Google Scholar
Buerger, (M. J.), 1948. Am. Mineral. 33, 101 Google Scholar
Carmichael, (I. S. E.), i960. J. Petrol. 1, 309–36.Google Scholar
Clarke, (P. D.)., 1965. The petrology of the Insch basic mass, Aberdeenshire, Unpubl. Ph.D. thesis, Univ. Edinburgh.Google Scholar
Clarke, (P. D.) and Wadsworth, (W. J.), 1970. Scott. J. Geol. 6, 7.CrossRefGoogle Scholar
Cox, (K. G.), Johnson, (R. L.), Monkman, (L. J.), Stillman, (C. J.), Vail, (J. R.), and Wood, (D. H.), 1965. Phil. Trans. R. Soc. A. 257, 71–218.Google Scholar
Deer, (W. A.) and Abbott, (D.), 1965. Mineral. Mag. 34, 177.Google Scholar
Gifford, (A. C), 1961. The Geology of Eastern Marangudzi, Southern Rhodesia. Unpub. Ph.D. thesis, Univ. London.Google Scholar
Green, (D. H.) 1968. In Hess & Poldervaart (editors) Basalt: Poldervaart treatise on rocks of basaltic composition, 2, 573–6oi Interscience.Google Scholar
Green, (D. H.) and Ringwood, (A. E.), 1964. Nature, 201, 1276–9.CrossRefGoogle Scholar
Hess, (H. H.), 1960. Stillwater Igneous Complex. Geol. Soc. Am. Mem. 80.Google Scholar
Howie, (R. A.), 1963. Mineral. Soc. Am. Spc. Pap. 1, 213–22.Google Scholar
Hytonen, (K.) and Schairer, (J. F.), 1961. Carnegie Inst. Wash. Yearb. 60, 125–41.Google Scholar
Kretz, (R.), 1961. J. Geol. 69, 361–87.CrossRefGoogle Scholar
Kretz, (R.) 1963. Ibid. 71, 773–85.Google Scholar
Kushiro, (I.), 1960. Am. J. Sci. 258, 548–54.CrossRefGoogle Scholar
Kushiro, (I.) 1962. Jap. J. Geol. Geogr. 33, 213.Google Scholar
Le Bas, (M. J.), 1962. Am. J. Sci. 260, 267–88.CrossRefGoogle Scholar
Lewis, (J. F.), 1967. Am. Mineral. 52, 42–51.Google Scholar
Muir, (I. D.) and Tilley, (C. E.), 1964. J. Petrol. 5, 409–34.CrossRefGoogle Scholar
Murray, (R. J.), 1954. Geol. Mag. 91, 17. 31.CrossRefGoogle Scholar
Poldervaart, (A.) and Hess, (H. H.) 1951. J. Geol. 59, 472–89.CrossRefGoogle Scholar
Rahman, (A. A. M. S.), 1975. Mineral. Mag. 40, 43–52.CrossRefGoogle Scholar
Ramberg, (H.) and DeVore, (G.), 1951. J. Geol. 59, 193–201.CrossRefGoogle Scholar
Rees, (G.) 1960. The Geology of West Marangudzi. Unpubl. Ph.D. Thesis, Univ. London.Google Scholar
Ringwood, (A. E.) and Green, (D. H.), 1964. Nature, 201, 566–7.CrossRefGoogle Scholar
Sakata, (Y.), 1957. Jap. J. Geol. Geog. 28, 161.Google Scholar
Thompson, (J. B.) 1947. Bull. Geol. Soc. Am. 58, 237.Google Scholar
Wilkinson, (J. F. G.), 1957. Geol. Mag. 94, 123–34.CrossRefGoogle Scholar
Wilkinson, (J. F. G.) 1966. Proc. R. Soc. New South Wales, 99, 69–77 (Browne Volume).Google Scholar