Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-27T06:57:03.178Z Has data issue: false hasContentIssue false

The Basal Rocks of the Tertiary at Uloa, Zululand, South Africa

Published online by Cambridge University Press:  01 May 2009

J. J. Frankel
Affiliation:
School of Applied Geology, University of New South Wales, Kensington, N.S.W., Australia.

Abstract

At Uloa in Zululand a nodule bed is the basal formation of a thin group of Tertiary sediments that rests on nearly horizontal Senonian silty mudstones. It contains mammillary, botryoidal, and cylindrical nodules, remanié Lower and Upper Cretaceous mollusca all ferruginized and partly pyritized, silicified Cretaceous wood, worn Tertiary sharks' teeth, and cetacean bone, phosphatized nodules of both Upper Cretaceous and Victoriella-bearing Eocene, and Tertiary glauconitic sandstone pebbles dated at 55 million years.

A coquina-like limestone (“Pecten Bed”) overlies the irregular upper surface of the nodule bed disconformably. Consideration of some of the megafossils, the absence of larger Foraminifera, and the presence of Orbulina universa suggest that the “Pecten Bed” is Middle to Upper Miocene in age.

Alternations of coarse and fine grained calcarenite layers that overlie the “Pecten Bed” disconformably, may be of youngest Miocene age.

The nature of the Tertiary rocks suggests shallow water sedimentation from the Eocene to latest Miocene, with several periods of transgression and regression, and slight epeirogenic or eustatic movement only.

Type
Articles
Copyright
Copyright © Cambridge University Press 1966

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

Biesiot, P. G., 1957. Miocene foraminifera from the Uloa sandstone. Trans. geol. Soc. S. Afr., 60, 6180.Google Scholar
Blow, W. H., 1956. Origin and evolution of the foraminiferal genus Orbulina d' Orbigny. Micropaleontology, 2, 5770.CrossRefGoogle Scholar
Bowler, J. M., 1963. Tertiary stratigraphy and sedimentation in The Geelong-Maude area, Victoria. Proc. roy. Soc. Vict., 76, pt. 1, 69137.Google Scholar
Carter, A. N., 1964. Tertiary foraminifera from Gippsland, Victoria and their stratigraphical significance. Mem. geol. Surv. Vict., 23, 154 pp.Google Scholar
Davies, D. H., 1964. The Miocene shark fauna of the southern St. Lucia area. Oceanogr. Res. Inst. Durban, Investl. Rep., 10, 116.Google Scholar
Eames, F. E. and Cox, L. R., 1956. Some Tertiary Pectinacea from East Africa, Persia and the Mediterranean region. Proc. malac. Soc. Lond., 32, 169.Google Scholar
Evernden, J. F. Curtis, G. H., Obradovich, J., and Kistler, R., 1961. On the evaluation of glauconite and illite for dating sedimentary rocks by the potassium-argon method. Geochim. cosmochim. Acta, 23, 7899.CrossRefGoogle Scholar
Frankel, J. J., 1960. The geology along the Umfolosi river, south of Mtubatuba, Zululand. Trans. geol. Soc. S. Afr., 63, 231252. Reply to Discussion, 256–263.Google Scholar
Frankel, J. J., and P., Bayliss, 1966. Ferruginized surface deposits from Natal and Zululand, South Africa. J. sediment. Petrol, (in the press).Google Scholar
Glaessner, M. F. and Mary, Wade, 1959. Revision of the foraminiferal family Victoriellidae. Micropaleontology, 5, 193212.CrossRefGoogle Scholar
King, L. C., 1953. A Miocene marine fauna from Zululand. Trans. geol. Soc. S. Afr., 56, 5991.Google Scholar
King, L. C., 1960. Discussion on paper by J. J. Frankel. Trans. geol. Soc. S. Afr., 63, 254–6.Google Scholar
King, L. C., and King, L. A., 1959. A reappraisal of the Natal monocline. S. Afr. geogr. J., 41, 1530.CrossRefGoogle Scholar
Kleywegt, R. J. A preliminary survey of a portion of the Uloa area. Unpubl. student essay, Univ. Natal, Durban (August, 1958).Google Scholar
Pettijohn, F. J., 1957. Sedimentary Rocks. Harper and Brothers, New York.Google Scholar
Ward, C. J. and Frankel, J. J., 1962. New occurrences of Miocene rocks in the lower Umfolosi river valley, Zululand. S. Afr. J. Sci., 58, 283–4.Google Scholar