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A Note on Possible Differentiation Trends in Tertiary to Recent Lavas of Kenya*

Published online by Cambridge University Press:  01 May 2009

J. B. Wright
J. B. Wright
Affiliation:
Department of Geology, University of Otago, Dunedin, New Zealand.
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Abstract

The distribution of Tertiary to Recent lavas in part of south-west Kenya is outlined, and attention drawn to the predominance of nepheline-rich Miocene lavas over other types west of the Rift Valley, which contrasts with the Pliocene olivine basalt-trachytecomendite association predominating within the Rift Valley. It is inferred that widespread Miocene phonolites west of the Rift Valley derived from a parent of approximate mela-nephelinitic composition, while within the Rift Valley extensive Pleistocene trachytes differentiated from an olivine basaltic parent. Plots of normative feldspathoid: feldspar versus silica, for analysed lavas from Kenya and Tanganyika, are used to illustrate the trends envisaged. The frequent association of nephelinitic lavas and carbonatite complexes in Kenya is discussed and the possibility mooted that the presence of nephelinite lavas may be indicative of nearby carbonatite complexes.

Type
Articles
Information
Geological Magazine , Volume 100 , Issue 2 , April 1963 , pp. 164 - 180
Copyright
Copyright © Cambridge University Press 1963

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Footnotes

*

Published by permission of the Commissioner, Mines and Geological Department, P.O. Box 30009, Nairobi, Kenya.

References

REFREENCES

Baker, B. H. (a) Geology of the South Magadi area.Google Scholar
Baker, B. H. (b) Geology of the Mount Kenya area.Google Scholar
Jennings, D. J. Geology of the Kapsabet Plateau.Google Scholar
Matheson, F. J. Geology of the Kajiado area.Google Scholar
Rix, P. Geology of the Kinna area.Google Scholar
Saggerson, E. P. (a) Geology of the Simba–Kibwezi area.Google Scholar
Saggerson, E. P. (b) Geology of the Loita Hills area.Google Scholar
Thomson, A. O., and Dodson, R. G.. Geology of the Naivasha area.Google Scholar
Walsh, J. Geology of the Eldama–Kabarnet area.Google Scholar
Williams, L. A. J. (a) Geology of the Mara River-Sianna area.Google Scholar
Williams, L. A. J. (b) Geology of the Amboseli area.Google Scholar
Wright, J. B. Geology of the Narok area.Google Scholar
Baker, B. H., 1958. Geology of the Magadi area. Geol. Surv. Kenya Rept., 42.Google Scholar
Barth, T. F. W., 1936. The crystallization process of basalt. Amer. J. Sci., 31, 321–351.CrossRefGoogle Scholar
Binge, F. W., 1962. Geology of the Kericho area. Geol. Surv. Kenya Rept., 50.Google Scholar
Bowen, N. L., 1928. Evolution of the Igneous Rocks. Princeton.Google Scholar
Bowen, N. L., 1937. Recent high-temperature research on silicates and its significance in igneous geology. Amer. J. Sci., 33, 1–21.CrossRefGoogle Scholar
Caswell, P. V., 1953. Geology of the Mombasa–Kwale area. Geol. Surv. Kenya Rept., 24.Google Scholar
Coombs, D. S., 1962. Basalt relationships illustrated by the Plagioclase-Ferroan Diopside-Olivine-Silica tetrahedron. Amer. Min., 47, 187.(Abstract.)Google Scholar
Downie, C., Humphries, D. W., Wilcockson, W. H., and Wilkinson, P., 1956. Geology of Kilimanjaro. Nature, 178, 828–830.CrossRefGoogle Scholar
Häkli, A., 1960. On high-temperature alkali feldspars of some volcanic rocks of Kenya and northern Tanganyika. Bull. comm. géol. Finlande, 188, 99–108.Google Scholar
Harkin, D. A., 1960. The Rungwe volcanics at the northern end of Lake Nyasa. Geol. Surv. Tanganyika, Mem. 11.Google Scholar
Joubert, P., 1957. Geology of the Namanga–Bissel area. Geol. Surv. Kenya Rept., 39.Google Scholar
Knorring, O. von, 1962. Geochemical characteristics of carbonatites. Nature, 144, 860–1.CrossRefGoogle Scholar
Lehmann, E., 1931. Beziehungen zwischen Kristallisation u. Differentiation in basaltischen Magmen. Min. Pet. Mitt., 41, 8–57.Google Scholar
McCall, G. J. H., 1957. Geology and groundwater conditions in the Nakuru area. M.O.W. (Hydraulic Branch) Tech. Rept., 3.Google Scholar
McCall, G. J. H., 1958. Geology of the Gwasi area. Geol. Surv. Kenya Rept., 45.Google Scholar
MacDonald, G. A., 1960. Dissimilarity of continental and oceanic rock types. J. Petr., 1, 172–7.Google Scholar
Mason, P., and Gibson, A. B., 1957. Geology of the Kalossia–Tiati area. Geol. Surv. Kenya Rept., 41.Google Scholar
Mountain, E. D., 1925. Potash oligoclase from Mt. Erebus, Antarctica, and anorthoclase from Mt. Kenya, E. Africa. Miner. Mag., 20, 331–345.Google Scholar
Ödman, O. H., 1930. Volcanic rocks of Mount Elgon in British East Africa. Geol. fören. förhandl., 52, 455–537.CrossRefGoogle Scholar
Pulfrey, W., 1949. Ijolitic rocks near Homa Bay, western Kenya. Quart. J. geol. Soc. Lond., 105, 425–459.CrossRefGoogle Scholar
Pulfrey, W., 1954. Alkaline syenites at Ruri, South Nyanza, Kenya. Geol. Mag., 91, 209–219.CrossRefGoogle Scholar
Saggerson, E. P., 1952. Geology of the Kisumu District. Geol. Surv. Kenya Rept., 21.Google Scholar
Schoeman, J. J., 1949. Geology of the Sotik District. Geol. Surv. Kenya Rept., 16.Google Scholar
Searle, D. L., 1952. Geology of the area north-west of Kitale township. Geol. Surv. Kenya Rept., 19.Google Scholar
Searle, D. L., 1954. Geology of the Sultan Hamud area. Geol. Surv. Kenya Rept., 29.Google Scholar
Shackleton, R. M., 1945. Geology of the Nyeri area. Geol. Surv. Kenya Rept., 12.Google Scholar
Shackleton, R. M., 1946. Geology of the country between Nanyuki and Maralal. Geol. Surv. Kenya Rept., 11.Google Scholar
Shand, S. J., 1937. The rocks of the Kedong scarp, Kenya Rift Valley. Geol. Mag., 74, 262–271.CrossRefGoogle Scholar
Smith, W. C., 1931. A classification of some rhyolites, trachytes, and phonolites from part of Kenya Colony, with a note on some associated basaltic rocks. Quart. J. geol. Soc. Lond., 87, 212–258.CrossRefGoogle Scholar
Smith, W. C., 1938. Petrographic description of volcanic rocks from Turkana, Kenya Colony, with notes on their field occurrence, from the manuscript of Mr. A. M. Champion. Quart. J. geol. Soc. Lond., 94, 507–553.CrossRefGoogle Scholar