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Petrographic Sub-provinces in the Tertiary to Recent Volcanics of Kenya

Published online by Cambridge University Press:  01 May 2009

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

Three sub-provinces are recognized in the volcanics of the southern half of Kenya as follows:—

(a) the Miocene phonolite sub-province, (b) the Mount Kenya phonolite/basanite sub-province, and (c) the Rift Valley trachyte/olivine basalt sub-province. Mela-nephelinitic lavas in the two phonolitic sub-provinces are shown to differ significantly in mineralogy, chemistry, and associated volcanics. The type of volcanic association likely to be related to carbonatite occurrences is briefly discussed.

Areas of exposed Miocene phonolite and Plio-Pleistocene trachyte are much greater than those of associated basic lavas, while intermediate types are almost lacking. Calculations show that assimilation of gneissic basement rocks by basanite (or olivine mela-nephelinite) and by olivine basalt may contribute to the development of phonolite and trachyte respectively. Available supporting evidence is discussed, both from Kenya and from similar volcanic provinces elsewhere. The additional amount of salic derivatives “which can be produced in this way is small, however, relative to the volume of basic parent involved.

Type
Articles
Information
Geological Magazine , Volume 102 , Issue 6 , December 1965 , pp. 541 - 557
Copyright
Copyright © Cambridge University Press 1965

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References

Aoki, K., 1963. The kaersutites and oxykaersutites from alkalic rocks of Japan and surrounding areas. J. Pet., 4, 198–210.CrossRefGoogle Scholar
Bailey, D. K., 1964. Crystal warping—A possible tectonic control of alkaline magmatism. J. Geophys. Res., 69, 1103–1111.CrossRefGoogle Scholar
Baker, B. H., 1958. Geology of the Magadi area. Geol. Surv. Kenya Rept., 42.Google Scholar
Baker, B. H., Geology of the Mt. Kenya area. Geol. Surv. Kenya Rept., unpub.Google Scholar
Benson, W. N., 1941, 1942. The basic igneous rocks of Eastern Otago and their tectonic environment, Parts 1–3. Trans. Roy. Soc. N.Z., 71, 208–222; 72, 85–110 and 160–185.Google Scholar
Binge, F. W., 1962. Geology of the Kericho area. Geol. Surv. Kenya Rept., 50.Google Scholar
Bowen, N. L., 1937. Recent high temperature research on silicates and its significance in igneous petrology. Amer. J. Sci., 33, 1–21.CrossRefGoogle Scholar
Brown, E. H., 1965. Geology of the Mount Stoker area, Eastern Otago. Pt. II—Volcanic geology. N.Z. J. Geol. Geophys. (in press).Google Scholar
Caswell, P. V., 1953. Geology of the Mombasa-Kwale area. Geol. Surv. Kenya Rept., 24.Google Scholar
Chayes, F., 1963. Relative abundance of intermediate members of the oceanic basalt-trachyte association. J. Geophys. Res., 68, 1519–1534.CrossRefGoogle Scholar
Coombs, D. S., 1963. Trends and affinities of basaltic magmas as illustrated on the diopside-olivine-silica diagram. Min. Soc. Amer., Spec. Pap., 1, 227–250.Google Scholar
Dawson, J. B., 1962. The Geology of Oldoinyo Lengai. Bull. Volc., 24, 349–388.CrossRefGoogle Scholar
Dodds, L. R., 1963. Geology of the Budle area, Central Otago. B.Sc.Hons. thesis, Univ. of Otago.Google Scholar
Downie, C., Humphries, D. W., Wilcockson, W. N., and Wilkinson, P., 1956. Geology of Kilimanjaro. Nature, 178, 828–830.CrossRefGoogle Scholar
Du Bois, C. G. B., Furst, J., Guest, N. J., Jennings, D. J.., 1963. Fresh natro-carbonatite lava from Oldoinyo L'Engai. Nature, 197, 445–6.CrossRefGoogle Scholar
Gibson, A. B., 1954. Geology of the Broderick Falls area. Geol. Surv. Kenya Rept., 26.Google Scholar
Harkin, D. A., 1960. The Rungwe volcanics at the northern end of Lake Nyasa. Geol. Surv. Tanganyika, Mem., 11.Google Scholar
King, B. C., 1960. Alkaline rocks of Eastern and Southern Africa. Pts. II and III. Sci. Progr., 48, 504–524, 709–720.Google Scholar
Le Maitre, R. W., 1962. Petrology of volcanic rocks, Gough Island, South Atlantic. Bull. geol. Soc. Amer., 73, 1309–1340.CrossRefGoogle Scholar
Le Maitre, R. W., and Gass, I. G, 1963. Occurrence of leucite in volcanic rocks from Tristan da Cunha. Nature, 198, 779–780.CrossRefGoogle 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
McCall, G. J. H., (unpub.). Geology of the Nakuru-Thomson's Falls—Lake Hannington area. Geol. Surv. Kenya Rept.Google Scholar
Mason, P., 1955. Geology of the Meru-Isolo area. Geol. Surv. Kenya Rept., 31.Google Scholar
Mason, P., and Gibson, A. B., 1957. Geology of the Kalossia-Tiati area. Geol. Surv. Kenya Rept., 41.Google Scholar
Nockolds, S. R., 1954. Average chemical compositions of some igneous rocks. Bull. geol. Soc. Amer., 65, 1007–1032.CrossRefGoogle Scholar
Pulfrey, W., 1949. Ijolitic rocks near Homa Bay, western Kenya. Quart. J. geol. Soc. Lond., 105, 425–459.CrossRefGoogle Scholar
Rix, P. (unpub.). Geology of the Kinna area. Geol. Surv. Kenya Rept.Google Scholar
Rix, P. (unpub.). Geology of the Kauro-Merille area. Geol. Surv. Kenya Rept.Google Scholar
Saggerson, E. P. (unpub.). Geology of the Simba-Kibwezi area. Geol Surv. Kenya Rept.Google Scholar
Saggerson, E. P. and Williams, L. A. J., 1964. Ngurumanite from Southern Kenya and its bearing on the origin of rocks in the Northern Tanganyika alkaline district. J. Pet., 5, 40–81.CrossRefGoogle Scholar
Schoeman, J. J., 1949. Geology of the Sotik District. Geol. Surv. Kenya Rept., 19.Google Scholar
Searle, D. L., 1952. Geology of the area north-west of Kitale township. Geol. Surv. Kenya Rept., 19.Google Scholar
Shackleton, R. M., 1946. Geology of the country between Nanyuki and Maralal. Geol. Surv. Kenya Rept., 11.Google Scholar
Shackleton, R. M., 1945. Geology of the Nyeri area. Geol. Surv. Kenya Rept., 12.Google Scholar
Shand, S. J., 1937. The rocks of the Kedong scarp, Kenya Rift Valley. Geol. Mag., 74, 262–271.CrossRefGoogle Scholar
Sikes, H. L., 1939. Notes on the geology of the country surrounding Nairobi. Geol. Surv. Kenya Pubn.Google 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., 1951. A review of some problems of African carbonatites. Quart. J. geol. Soc. Lond., 112, 189–220.CrossRefGoogle Scholar
Thomson, A. O., and Dodson, R. G. (unpub.). Geology of the Naivasha area. Geol. Surv. Kenya Rept.Google Scholar
Turner, F. J., and Verhoogen, J., 1951. Igneous and metamorphic petrology.Google Scholar
Walsh, J. (unpub.). Geology of the Eldama Ravine—Kabarnet area. Geol. Surv. Kenya Rept.Google Scholar
Wilkinson, F. J. G., 1961. Some aspects of the calciferous amphiboles oxyhornblende, kaersutite and barkevikite. Amer. Min., 46, 304–354.Google Scholar
Wimmenauer, W., 1952. Petrographische Untersuchungen en einigen basischen Eruptivgesteinen des Oberrheingebietes. N. Jb. Miner., 83, 375–432.Google Scholar
Wimmenauer, W., 1957, 1959, 1963. Beiträge zur Petrographie des Kaiserstuhls, I; II, III; VI, VII. N. Jb. Miner., 91, 131–150; 93, 133–173; 99, 231–276.Google Scholar
Wimmenauer, W., 1962. Zur Petrogenese der Eruptivgesteine und Karbonatite des Kaiserstuhls. N. Jb. Miner. Mh., 1, 1–11.Google Scholar
Wright, J. B., 1963. A note on possible differentiation trends in Tertiary to Recent lavas of Kenya. Geol. Mag., 100, 164–180.CrossRefGoogle Scholar
Wright, J. B., (unpub.). Geology of the Narok area. Geol. Surv. Kenya Rept.Google Scholar
Wright, J. B., and Rix, P., 1965. Trough faulting and sedimentation in eastern central Kenya. Overseas Geol. and Min. Res. Bull., 10, no. 1 (in press).Google Scholar
Yoder, H. S., and Tilley, C. E., 1962. Origin of basalt magmas: An experimental study of natural and synthetic rock systems. J. Pet., 3, 342–532.CrossRefGoogle Scholar