Textural characteristics, mode of transportation and depositional environment of the Stormberg Group in the Eastern Cape, South Africa: evidence from grain size and lithofacies analyses

• Autorzy: Chima Priscilla , Baiyegunhi Christopher

Identyfikatory

DOI

10.2478/logos-2022-0005

• Języki publikacji: EN

Abstrakty

EN

The Stormberg Group comprises the Molteno, Elliot and Clarens formations and is one of four stratigraphical groups that make up the Karoo Supergroup in South Africa. The group is the highest unit in the Karoo Basin, representing the final phase of preserved sedimentation. The major problem with the Stromberg Group is that the mode of transport, hydrodynamic energy conditions and depositional environment are still poorly understood. For the present paper, grain size and lithofacies studies on selected sandstones from the Molteno, Elliot and Clarens formations were performed so as to elucidate their textural characteristics, depositional processes, sedimentation mechanisms and hydrodynamic energy conditions and to discriminate different depositional environments. The statistical parameters of grain size distribution (mean grain size, standard deviation, skewness and kurtosis) show that the sandstones are predominantly unimodal, fine grained, moderately well sorted, mesokurtic and near symmetrical. The bivariate diagrams of the aforementioned statistical parameters demonstrate that river and aeolian dune had the greatest impact on the depositional environments. Likewise, the C-M pattern (Passega diagram) shows that the sandstones were mostly deposited through tractive current process. Furthermore, the C-M diagram reveals the prevalence of rolling, suspension and graded suspension modes of sediment transportation. Seventeen sedimentary lithofacies were identified and grouped into seven lithofacies associations. These lithofacies associations indicate braided channel, overbank and swamp deposits for the Molteno Formation, alluvial fan/floodplain and playa deposits for the Elliot Formation and aeolian deposits for the Clarens Formation.

Słowa kluczowe

EN

grain size distribution; textural parameters; lithofacies classification; hydrodynamic energy conditions; Triassic; Jurassic

PL

rozkład wielkości ziarna; parametry teksturalne; klasyfikacja litofacji; warunki hydrodynamiczne; warunki energetyczne; trias; jura

• Wydawca: Uniwersytet im. Adama Mickiewicza. Instytut Geologii
• Czasopismo: Geologos
• Rocznik: 2022
• Tom: Vol. 28, No. 1
• Strony: 61--78
• Opis fizyczny: Bibliogr. 47 poz.

Twórcy

autor

Chima Priscilla

• Department of Geosciences, Midlands State University, Private Bag 9055, Gweru, Zimbabwe

autor

Baiyegunhi Christopher

• Department of Geology and Mining, University of Limpopo, Private Bag X1106, Sovenga 0727, Limpopo Province, South Africa

Bibliografia

• Amaral, E.A. & Pryor, W.A., 1977. Depositional environment of St. Peters sandstone deduced by textural analysis. Journal of Sedimentary Petrology 47, 32-52.
• Baiyegunhi, C. & Liu, K., 2021. Sedimentary facies, stratigraphy, and depositional environments of the Ecca Group, Karoo Supergroup in the Eastern Cape Province of South Africa. Open Geosciences 13, 748–781.
• Boggs, S., 2006. Principles of Sedimentology and Stratigraphy (4th edition). Pearson, Prentice Hall, 662 pp.
• Bordy, E.M. & Catuneanu, O., 2002. Sedimentology of the lower Karoo Supergroup fluvial strata in the Tuli Basin, South Africa. Journal of African Earth Science 35, 503–521.
• Bordy, E.M., Hancox, J.P. & Rubidge, B.S., 2004a. Provenance study of the Late Triassic – Early Jurassic Elliot Formation, main Karoo Basin, South Africa. South African Journal of Geology 107, 587–602.
• Bordy, E.M., Hancox, P.J. & Rubidge, B.S., 2004b. Basin development during the deposition of the Elliot Formation (Late Triassic – Early Jurassic), Karoo Supergroup, South Africa. South African Journal of Geology 107, 395–410.
• Bordy, E.M., Hancox, P.J., & Rubidge, B.S., 2005. The contact of the Molteno and Elliot Formations through the main Karoo Basin, South Africa: a second-order sequence boundary. South African Journal of Geology 108, 349–362.
• Catuneanu, O., Hancox, P.J. &d Rubidge, B.S., 1998. Reciprocal flexural behaviour and contrasting stratigraphies: a new basin development model for the Karoo retro-arc foreland system, South Africa. Basin Research 10, 417–439.
• Catuneanu, O., Wopfner, H., Eriksson, P.G., Cairncross, B., Rubidge, B.S., Smith, R.M.H. & Hancox, P.J., 2005. The Karoo Basins of South-Central Africa. Journal of African Earth Sciences 43, 211–253.
• Christie, A.D.M., 1981. Stratigraphy and sedimentology of the Molteno Formation in the Elliot and Indwe area, Cape Province. University of Natal, South Africa, 182 pp.
• Cole, D.I., 1992. Evolution and development of the Karoo Basin. [In:] De Wit, M.J. & Ransome, I.G.D. (Eds): Inversion Tectonics of the Cape Fold Belt. Karoo and Cretaceous Basins of Southern Africa. Balkema, Rotterdam, 87–99.
• Duck, R.W., 1994. Applications of the QDa-Md method of environmental discrimination to particle size analyses of fine sediments by pipette and sedigraph methods: a comparative study. Earth Surface Processes Landforms 19, 525-529.
• Eriksson, P.G., 1986. Aeolian dune and alluvial fan deposits in the Clarens Formation of the Natal Drakensberg. Transactions Geological Society of South Africa 89, 389–393.
• Folk, R.L., 1966. A review of grain-size parameters. Sedimentology 6, 73–93.
• Folk, R.L., 1974. Petrology of sedimentary rocks. Hemphill Publ. Co., Austin, 182 pp.
• Folk, R.L. & Ward, W., 1957. Brazos river bar: a study in the significance of grain size parameters. Journal of Sedimentary Petrology 27, 3–26.
• Friedman, G.M., 1958. Determination of sieve-size distribution from thin-section data for sedimentary petrological studies. Journal of Geology 66, 394-416.
• Friedman, G.M., 1961. Distinction between dune, beach and river sands from their textural characteristics. Journal of Sedimentary Petrology 31, 514–529.
• Friedman, G.M., 1967. Dynamic processes and statistical parameters compared for size frequency distribution of beach and river sands. Journal of Sedimentary Petrology 37, 327–354.
• Friedman, G.M., 1979. Differences in size distribution of populations of particles among sands of various origin. Sedimentology 26, 859–862.
• Hancox, P.J., 2000. The continental Triassic of South Africa. Zentralblatt für Geologie und Paläontologie. I, 3, 1285–1324.
• Holzförster, F., 2007. Lithology and depositional environments of the Lower Jurassic Clarens Formation in the Eastern Cape, South Africa. South African Journal of Geology 110, 543–560.
• Johnson, M.R., 1976. Stratigraphy and Sedimentology of the Cape and Karoo Sequences in the Eastern Cape Province. Rhodes University, South Africa, 366 pp.
• Johnson, M.R., 1991. Sandstone petrography, provenance and plate tectonic setting in Gondwana context of the south-eastern Cape-Karoo Basin. South African Journal of Geology 94, 137–154.
• Johnson, M.R., van Vuuren, C.J., Hegenberger, W.F., Key, R. & Shoko, U., 1996. Stratigraphy of the Karoo Supergroup in southern Africa: an overview. Journal of African Earth Sciences 23, 3–15.
• Johnson, M.R., van Vuuren, C.J., Visser, J.N.J., Cole, D.I., Wickens, H. de V., Christie, A.D.M., Roberts, D.L & Brandl, G., 2006. Sedimentary Rocks of the Karoo Supergroup. [In:] Johnson, M.R., Anhaeusser, C.R. & Thomas, R.L. (Eds): The Geology of South Africa. Geological Society of South Africa, Johannesburg, 461–499.
• Katemaunzanga, D. & Gunter, C.J., 2009. Lithostratigraphy, sedimentology, and provenance of the Balfour Formation (Beaufort Group) in the Fort Beaufort–Alice Area, Eastern Cape Province, South Africa. Acta Geologica Sinica 83, 902 –916.
• Kent, L.E. & Hugo, P.J., 1978. Aspects of the revised South Africa stratigraphic classification: a proposal for the chronostratigraphic subdivision of the Precambrian. American Association of Petroleum Geologists, Studies in Geology 6, 367–379.
• Miall, A.D., 1977. A review of the braided river depositional environment. Earth Science Reviews 13, 42–54.
• Miall, A.D., 1985. Architectural-element analysis: a new method of facies analysis applied to fluvial deposits. Earth Science Reviews 22, 261–308.
• Miall, A.D., 1996. Geology of fluvial deposits. Blackwell Scientific Publ., Oxford, 582 pp.
• Middleton, G.V., 1978. Facies. [In:] R.W. Fairbridge & J. Bourgeois (Eds): Encyclopaedia of sedimentology. Dowden, Hutchinson & Ross, Stroudsburg, 323–325.
• Moiola, R.J. & Weiser, D., 1968. Textural parameters: an evaluation. Journal of Sedimentary Petrology 38, 45–53.
• Passega, R., 1957. Texture as characteristics of clastic deposition. American Association of Petroleum Geologists Bulletin 41, 1952–1984.
• Passega, R., 1964. Grain size representation by C-M pattern as a geological tool. Journal of Sedimentary Petrology 34, 830–847.
• Passega, R., 1972. Sediment sorting related to basin mobility and environment. American Association of Petroleum Geologists 56, 2440–2450.
• Reading, H.G., 1996. Sedimentary environments processes, facies and stratigraphy. 3rd Edition. Blackwell, 422–448.
• Reid, L.M & Dunne, T., 1996. Rapid Evaluation of Sediment Budgets. Catena, Reiskirchen, 164 pp.
• Rubidge, B.S., 1995. Biostratigraphy of the Beaufort Group (Karoo Supergroup). South African Committee for Stratigraphy. Geological Survey of South Africa Biostratigraphic Series 1, 37–46.
• Smith, R.M.H., Eriksson, P.G. & Botha, W.J., 1993. A review of the stratigraphy and sedimentary environments of the Karoo-aged basins of Southern Africa. Journal of African Sciences 16, 143–169.
• South African Committee for stratigraphy, SACS 1980. Stratigraphy of South Africa. Part I. Lithostratigraphy of the Republic of South Africa, South West-Africa/Namibia, and the Republics of Bophuthatswana, Transkei, and Venda. Geological Survey South Africa Handbook 8, 690 pp.
• Stewart, H.B., 1958. Sedimentary reflection on depositional environment, in San Mignel lagoon, Baju California, Mexico. AAPG Bulletin 42, 2567–2618.
• Tanner, W.F., 1991. Suite statistics: The hydrodynamic evolution of the sediment pool. [In:] Syvitski, J.P.M. (Ed.): Principles, Methods and Application of Particle Size Analysis. Cambridge University Press, 342–368.
• Turner, B.R., 1975. The stratigraphy and sedimentary history of the Molteno Formation in the Main Karoo Basin of South Africa and Lesotho. University of Witwatersrand, 243–278.
• Turner, B.R., 1983. Braid plain deposition of the Upper Triassic Molteno Formation in the main Karoo (Gondwana) Basin, South Africa. Sedimentology 30, 77–89.
• Visser, J.N.J. & Botha, B.J.V., 1980. Meander belt, point bar, crevasse splay and aeolian deposits from the Elliot Formation in Barkly Pass, north-eastern Cape. Transactions of the Geological Society of South Africa 83, 55–62.
• Wentworth, C.K., 1929. Method of computing mechanical composition types in sediments. Bulletin of the Geological Society of America 40, 771–790.

Uwagi

Opracowanie rekordu ze środków MEiN, umowa nr SONP/SP/546092/2022 w ramach programu "Społeczna odpowiedzialność nauki" - moduł: Popularyzacja nauki i promocja sportu (2022-2023).