Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-26T16:19:00.840Z Has data issue: false hasContentIssue false
  • English
  • Français

Lithofacies and Environments of Bed I, Olduvai Gorge, Tanzania

Published online by Cambridge University Press:  20 January 2017

Richard L. Hay
Richard L. Hay*
Affiliation:
Department of Geology and Geophysics, University of California, Berkeley, California 94720 USA
Get access Rights & Permissions [Opens in a new window]

Abstract

Bed I in Olduvai Gorge spans the interval from about 1.7 to 2.0 m.y.a., and all evidences of hominid activity at Olduvai are within the latter half of this period. Bed I was deposited in a closed basin approximately 25 km in average diameter, and it can be subdivided into five lithologically different but partly time-equivalent rock assemblages, or lithologic facies, each of which was deposited in the same geographic environment or closely related series of environments. These lithofacies comprise lake deposits, lake-margin deposits, alluvial-fan deposits, alluvial-plain deposits, and lava flows.

Alluvial-plain deposits form the lowermost part of Bed I, and they presumably interfinger northeastward with lake deposits in an area not now exposed. Discharge of the lavas diplaced the lake westward to a position it occupied through the latter half of the deposition of Bed I. The lake fluctuated greatly in salinity, level, and extent, and at times of low level it was highly saline and generally ranged between 7 and 10 km in average diameter. At times of high level it was as much as 15 km in diameter and was relatively fresh, at least along its southeastern margin. The lake-margin deposits accumulated on the zone of relatively flat terrain that was flooded at times of high level. Lake-margin deposits interfinger eastward with deposits of an alluvial fan of pyroclastic materials produced in an explosive phase of the volcano Olmoti. The climate at the time of Bed I was relatively dry although somewhat wetter than the present climate in the same region today.

Type
Original Articles
Information
Quaternary Research , Volume 3 , Issue 4 , December 1973 , pp. 541 - 560
Copyright
University of Washington

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

Brock, A., Hay, R.L., Brown, F.H., (1972)Magnetic stratigraphy of Olduvai Gorge and Ngorongoro, Tanzania (abstract). Geological Society of America Abstracts with Programs for 1972 457.Google Scholar
Curtis, G.H., Hay, R.L., (1972)Further geologic studies and K-Ar dating of Olduvai Gorge and Ngorongoro Crater. Bishop, W.W., Miller, J.A., Calibration of Human Evolution Scottish Academic Press Edinburgh and London 289–301.Google Scholar
Fleischer, R.L., Price, P.B., Walker, R.M., Leakey, L.S.B., (1969)Fission-track dating of Bed I, Olduvai Gorge. Science 148, 72–74 Graf, D.L., Geochemistry of carbonate sediments and sedimentary carbonate rocks, Part IV-A, Isotopic composition and chemical analyses Illinois Geological Survey 42Circular 308.CrossRefGoogle Scholar
Greenwood, P.H., Todd, E.J., (1970)Fish remains from Olduvai. Leakey, L.S.B., Savage, R.J.G., Fossil Vertebrates in Africa Vol. 2, Academic Press London and New York 225–241.Google Scholar
Grommé, C.S., Hay, R.L., (1971)Geomagnetic polarity epochs: age and duration of the Olduvai normal polarity epoch. Earth and Planetary Science Letters 10, 179–185.CrossRefGoogle Scholar
Grommé, C.S., Reilly, T.A., Mussett, A.E., Hay, R.L., (1970)Paleomagnetism and potassium-argon ages of volcanic rocks of Ngorongoro Caldera, Tanzania. Geophysical Journal of the Royal Astronomical Society 22, 101–115.CrossRefGoogle Scholar
Hay, R.L., (1966)Zeolites and zeolitic reactions in sedimentary rocks. Geological Society of America Special Paper 85 130.Google Scholar
Hay, R.L., (1968)Chert and its sodium-silicate precursors in sodium-carbonate lakes of East Africa. Contribution to Mineralogy and Petrology 17, 255–274.CrossRefGoogle Scholar
Hay, R.L., (1970)Silicate reactions in three lithofacies of a semi-arid basin, Olduvai Gorge, Tanzania. Morgan, B.A., Mineralogical Society of America Special Paper No. 3 237–255.Google Scholar
Hay, R.L., (1971)Geologic background of Beds I and II. Olduvai Gorge Vol. 3, Cambridge University Press M. D. Leakey 9–18.Google Scholar
Isaac, G.L., (1967)The stratigraphy of the Peninj Group-early middle Pleistocene formations west of Lake Natron, Tanzania. Bishop, W.W., Clark, J.D., Background to Evolution in Africa University of Chicago Press 229–257.Google Scholar
Leakey, L.S.B., (1965)Olduvai Gorge, 1951–1961. Cambridge University Press 118.Google Scholar
Leakey, M.D., (1971)Olduvai Gorge. Vol. 3, Cambridge University Press 306.Google Scholar
O'Neil, J.R., Hay, R.L., (1973)O18/O16• ratios in cherts associated with the saline lake deposits of East Africa. Earth and Planetary Science Letters 19, 257–266.CrossRefGoogle Scholar
Price, W.A., (1963)Physicochemical and environmental factors in clay dune genesis. Journal of Sedimentary Petrology 33, 766–778.Google Scholar
Reck, H., (1951)A preliminary survey of the tectonics and stratigraphy of Olduvai. Leakey, L.S.B., Olduvai Gorge Cambridge University Press 5–19.Google Scholar
Selley, R.C., (1970)Ancient Sedimentary Environments. Cornell University Press 224.Google Scholar
Verdcourt, B., (1963)The Miocene nonmarine mollusca of Rusinga Island Lake Victoria, and other localities in Kenya. Palaeontographica Bd. 121, 1–37Part A.Google Scholar