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Ignimbrite vents in the Sabaloka cauldron, Sudan

Published online by Cambridge University Press:  01 May 2009

D. C. Almond
D. C. Almond
Affiliation:
School of Geology, Kingston Polytechnic, Penrhyn Road, Kingston upon Thames, Surrey
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Summary

Large ignimbrite dykes continuous with an overlying sheet of rhyolitic ignimbrite have been found at two localities in the centrally-subsided block of the Sabaloka cauldron. There is good evidence that these dykes fed ash-flow eruptions. Other possible feeder vents occur along the marginal fracture zone of the cauldron but evidence for the origin of some of these structures is ambiguous. Ignimbrites within the dyke-shaped feeders contain a very strong eutaxitic foliation oriented parallel to the contacts and this feature is thought to result from inwardly-directed pressures exerted by the dyke walls during a collapse which followed eruption of the ash-flows. Vents of this type are believed to originate by permissive intrusion through the roof of a shallow-seated magma chamber, in contrast to forcefully injected diatreme vents. A broad genetic classification of these bodies is suggested, based on their mode of emplacement.

Type
Articles
Information
Geological Magazine , Volume 108 , Issue 2 , May 1971 , pp. 159 - 176
Copyright
Copyright © Cambridge University Press 1971

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References

Almond, D. C. 1967. Discovery of a Tin-tungsten Mineralization in Northern Khartoum Province, Sudan. Geol. Mag. 104, 1–12.CrossRefGoogle Scholar
Coe, K. 1966. Intrusive tuffs of west Cork. Q. Jl geol. Soc. Lond. 122, 1–28.CrossRefGoogle Scholar
Cloos, H. 1941. Bau und Tätigkeit von Tuffschloten. Untersuchungen an dem Schwäbischen vulkan. Geol. Rdsch. 32, 709–800.CrossRefGoogle Scholar
Delany, F. M. 1954. Recent contributions to the geology of the Anglo-Egyptian Sudan. Int. geol. Cong., 19th, Algeria. C.R. XX, Ass. Serv. Geol. Africaines, pt. I, 11–18.Google Scholar
Delany, F. M. 1955. Ring structures in the northern Sudan. Ecl. geol. helv. 48, 133–48.Google Scholar
Delany, F. M. 1958. Observations on the Sabaloka Series of the Sudan. Trans. geol. Soc. S. Afr. 61, 111–24.Google Scholar
Francis, E. H. 1959. A volcanic vent in the Bogside Mines, Fife. Geol. Mag. 96, 457–69.CrossRefGoogle Scholar
Francis, E. H. 1960. Intrusive tuffs related to the Firth of Forth Volcanoes. Trans. Edinb. geol. Soc. 18, 32–50.CrossRefGoogle Scholar
Francis, E. H. 1962. Layered diatremes: A discussion. J. Geol. 70, 499–500.CrossRefGoogle Scholar
Fries, C. Jr, 1963. Volumes and weights of pyroclastic material, lava, and water erupted by Paricutin volcano, Michoacan, Mexico. Trans. Am. geophys. Union, 34, 603–16.Google Scholar
Jacobson, R. R. E., Macleod, W. N. & Black, R. 1958. Ring-complexes in the Younger Granite province of northern Nigeria. Mem. geol. Soc. Lond. 1.Google Scholar
Koronovski, N. V. 1969. Structure of necks of ignimbrite and tuffolava complexes in the Northern Caucasus (in abstract). Symposium on Volcanoes and their Roots, IAVCEI, Oxford, 1969.Google Scholar
Leva, M., 1959. Fluidization. New York.Google Scholar
Lewis, J. B. 1969. The fluidization of solid particles. Proc. geol. Soc. Lond. no. 1655, 106–10.Google Scholar
Milanovski, E. E. & Koronovski, N. V. 1965. ‘Tuffolavas’ and related formations of Central Caucasus. Bull. volcan. 28, 3–11.CrossRefGoogle Scholar
Matheson, G. L., Herbst, W. A. & Holt, P. H. 1949. Characteristics of fluid–solid systems. Ind. Eng. Chem. 45, 1174–7.Google Scholar
Reynolds, D. L. 1954. Fluidization as a geological process, and its bearing on the problem of intrusive granites. Am. J. Sci. 252, 577–614.CrossRefGoogle Scholar
Reynolds, D. L. 1969. Fluidization as a volcanological agent. Proc. geol. Soc. Lond. no. 1655, 110–15.Google Scholar
Ross, C. S. & Smith, R. L. 1961. Ash-flow Tuffs: Their Origin, Geologic Relations and Identification. Prof. Pap. U.S. geol. Surv., 366.Google Scholar
Smith, R. L. 1960. Ash flows. Bull. geol. Soc. Am. 71, 795–842.CrossRefGoogle Scholar
Taylor, G. C. 1958. The 1951 eruption of Mount Lamington, Papua. Bull. Bureau Min. Resour. Geol. Geophys., Aust. 38.Google Scholar
Toms, B. A. 1958. Fundamental techniques: Fluids, in Eirich, (Ed.): Rheology, Theory and Application. New York.Google Scholar
Vennard, J. K. 1961. Elementary fluid mechanics. New York and London.Google Scholar
Whiteman, A. J. (In press) Geology of Sudan Republic.Google Scholar
Wilshire, H. G. 1961. Layered diatremes near Sydney, New South Wales. J. Geol. 69, 473–84.CrossRefGoogle Scholar