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Foraminifera

Life > Eukaryotes > Rhizaria

Foraminifera are microscopic single-celled animals which construct tiny shells, usually about 0.30 to 0.60 mm diameter, that have provided us with an extremely detailed biostratigraphic record of life on Earth from the late Precambrian to the present day (about 650 million years). Foraminifera live in saline environments, mainly in the sea, and often occur in considerable abundance: a small pinch of sea-floor sediment may contain well over 5000 foraminifera shells. They also live successfully in artesian borehole water beneath the Gobi and Sahara deserts, in saline springs in the Namib Desert, and widely in coastal lakes around the world where there is some saline influence. At times of particularly high temperatures on Earth, during the Carboniferous-Permian, the Jurassic-Cretaceous, and the Palaeocene-Eocene and Miocene periods, some foraminifera inhabiting coral reef lagoon environments began evolving rapidly, during which time their shell also rapidly increased in size. The largest foraminifera shells ever are about 10 cm long and shaped like a cigar. In South Africa the oldest foraminifera are known in black shales and slates in the Bokkeveld Series (Devonian) and in the Dwyka-Ecca black slates of the Great Karoo Basin (Permian-Triassic). They are still abundant around South African shores, but are now greatly changed.

Foraminifera shells are a valuable tool for finding out the age of marine rocks, or a rock succession, because of their incredible abundance and diversity through the world’s oceans through time. Therefore statistical confidence levels on foraminiferal assemblages are far higher than those gained from vertebrates or dinosaurs, which are researched almost always with a few incomplete skeletons. Some live in sea-floor environments (benthic foraminifera): others float at different levels in the world’s oceans (planktic foraminifera). Foraminifera can tell you precise ages of marine rocks, and the depositional environment that prevailed at the time those rocks were laid down. Foraminifera can help you correlate geological events in the Pacific Ocean with those in the Atlantic Ocean. Foraminifera tell you what the turbulence of the water was like, whether the water was well-oxygenated or not, whether the sedimentation rate was fast or slow, whether there is any reworking of foraminifera from older underlying rocks, and the age of those rocks.

There is a larger literature available for foraminifera than for any other invertebrate group. This is because they have been widely used especially in the oil industry, but also in the diamond exploration industry, around the world since about the 1900’s.

And the reason for such world-wide enthusiasm over such tiny amimal shells? Despite their small size these microscopic critters are extraordinarily beautiful. Every day one is finding something new from Africa.

Text by Ian McMillan

Publications on southern African Foraminifera

Note: These publications are mainly those authored or co-authored by Ian McMillan.

Genera articles

  • Dale, D.C. & McMillan, I.K. 1997. Tiny animals, tiny fossils. Earthyear, the Essential Environmental Guide, Cape Town 16: 98-99.

  • Dale, D.C. & McMillan, I.K. 1998. Microscopic planktonic animals off the African coast. Earthyear, the Essential Environmental Guide, Cape Town 17: 46-47.

  • Dale, D.C. & McMillan, I.K. 1998. A coast of giant rivers – the west coast in the time of the dinosaurs. Earthyear, the Essential Environmental Guide, Cape Town 18: 92-93.

  • Dale, D.C. & McMillan, I.K. 1999. On the Beach. A Field Guide to the Late Cainozoic Micropalaeontological History, Saldanha Region, South Africa. Cameron Design Publishers, Cape Town/ Hirt & Carter Printers, Cape Town: 1-127.

  • Dale, D.C. & McMillan, I.K. 1999. How do microscopic fossils help diamond exploration? Earthyear, the Essential Environmental Guide, Cape Town 20: 114-115.

  • Dale, D.C. & McMillan, I.K. 2002. The Pliocene, or how to correlate sediments using microfossils. Earthyear, the Essential Environmental Guide, Johannesburg 26: 18-19 (for 2003).

Scientific papers

  • Compton, J.S., Mulabisana, J, & McMillan, I.K. 2002. Origin and age of phosphorite from the Last Glacial Maximum to Holocene transgressive succession off the Orange River, South Africa. Marine Geology 186: 243-261.

  • Compton, J.S., Wigley, R. & McMillan, I.K. 2004. Late Cenozoic phosphogenesis on the western shelf of South Africa in the vicinity of the Cape Canyon. Marine Geology 206: 19-40.

  • Cooper, J.AG. & McMillan, I.K. 1987. Foraminifera of the Mngeni estuary, Durban, and their sedimentological significance. South African Journal of Geology 90 (4): 489-498.

  • Dale, D.C. & McMillan, I.K. 1997. Late Cretaceous (Early Turonian to Late Coniacian) hyposaline agglutinating foraminiferal biostratigraphy of the proximal Orange Basin, western offshore, South Africa, and southernmost offshore Namibia. Abstract, 3rd. Colloquium on Stratigraphy and Palaeogeography of the South Atlantic (Yaoundé, Cameroun, March, 1997).

  • Dale, D.C. & McMillan, I.K. 1998. Mud belt and middle shelf benthonic and planktonic foraminiferal assemblages compared through the Holocene successions at two tropical African (Sierra Leone) and two temperate African (western offshore, South Africa) sites. South African Journal of Science 94 (7): 319-340. (SASQUA meeting, Cape Town, 1995).

  • Dale, D.C. & McMillan, I.K. 2000. Pliocene foraminifera and biostratigraphic correlations of the African continental margin of South Africa and southern Namibia. Abstract, abstracts volume, 14th African Colloquium on Micropalaeontology (Luanda, Angola, May 2000).

  • Dingle, R.V., McMillan, I.K., Majoran, S. & Bisset, L. 2001. Palaeo-oceanographical implications of Early-Middle Miocene subtropical ostracods faunas from the continental shelf of the S.E. Atlantic Ocean. Palaeogeography, Palaeoclimatology, Palaeoecology 173: 43-60.

  • Franceschini, G., McMillan, I.K. & Compton, J.S. 2005. Foraminifera of Langebaan salt marsh and their application to the interpretation of Late Pleistocene depositional environments at Monwabisi, False Bay coast, South Africa. South African Journal of Geology 108 (2): 285-296.

  • Gibbons, M.J., Sulaiman, A., Hissman, K., Schauer, J., McMillan, I. & Wickens, P.A. 2000. Video observations on the habitat association of demersal nekton in the midshelf benthic environment off the Orange River, Namibia. South African Journal of Marine Science 22: 1-7.

  • Lindsay, P., Mason, T.R., Pillay, S. & Wright, C.I. 1996. Sedimentology and dynamics of the Mfulozi estuary, north Kwazulu-Natal, South Africa. South African Journal of Geology 99 (3): 327-336 (Appendix 1 by I.K. McMillan).

  • Loydell, D.K., McMillan, I.K. & Barron, H. 1988. Muellerisphaerids from the Llandovery of western mid Wales. Journal of Micropalaeontology 7 (2): 243-246.

  • McLachlan, I.R., Brenner, P.W. & McMillan, I.K. 1976. The stratigraphy and micropalaeontology of the Cretaceous Brenton Formation and the PB-A/1 well, near Knysna, Cape Province. Transactions of the Geological Society of South Africa 79 (3): 341-370.

  • McLachlan, I.R. & McMillan, I.K. 1976. Review and stratigraphic significance of southern Cape Mesozoic palaeontology. Transactions of the Geological Society of South Africa 79 (2): 197-212.

  • McLachlan, I.R. & McMillan, I.K. 1979. Microfaunal biostratigraphy, chronostratigraphy and history of Mesozoic and Cenozoic deposits on the coastal margin of South Africa. In: Anderson, A.M. & Van Biljon, W.J. (eds.), Some Sedimentary Basins and Associated Ore Deposits of South Africa (Geokongres ’77). Geological Society of South Africa, Special Publication 6: 161-181.

  • McLachlan, I.R., McMillan, I.K. & Brenner, P.W. 1976. Micropalaeontological study of the Cretaceous beds at Mbotyi and Mngazana, Transkei, South Africa. Transactions of the Geological Society of South Africa 79 (3): 321-340.

  • McMillan, I.K. 1974. Recent and Relict Foraminifera from the Agulhas Bank, South African Continental Margin. Unpublished M.Sc. thesis, University College of Wales, Aberystwyth: 1-97.

  • McMillan, I.K. 1986. Cainozoic planktonic and larger foraminifera distributions around southern Africa and their implications for past changes of oceanic water temperatures. South African Journal of Science 82 (2): 66-69.

  • McMillan, I.K. 1987. Late Quaternary Foraminifera from the Southern Part of Offshore South West Africa/Namibia. Unpublished Ph.D. thesis, University College of Wales, Aberystwyth: 1-565.

  • McMillan, I.K. 1986. Tertiary to Recent foraminifera of the Algoa Bay area. Institute of Coastal Research, University of Port Elizabeth, Bulletin 12: 76-80.

  • McMillan, I.K. 1987. The genus Ammonia Brűnnich, 1772 (Foraminiferida) and its potential for elucidating the later Cenozoic stratigraphy of South Africa. South African Journal of Science 83 (1): 32-42.

  • McMillan, I.K. 1989. Victoriella conoidea (Rutten, 1914): a guide foraminifera for the later Aquitanian (Early Miocene) rocks of southern Africa. South African Journal of Geology 92 (2): 95-101.

  • McMillan, I.K. 1990. Foraminifera from the Late Pleistocene (latest Eemian to earliest Weichselian) shelly sands of Cape Town city centre, South Africa. Annals of the South African Museum 99 (5): 121-186.

  • McMillan, I.K. 1990. Foraminiferal biostratigraphy of the Barremian to Miocene rocks of the Kudu 9A-1, 9A-2 and 9A-3 boreholes. Communications of the Geological Survey of Namibia 6: 23-29.

  • McMillan, I.K. 1990. Foraminiferal definition and possible implications of the major mid-Cretaceous (Albian to Coniacian) hiatuses of southernmost Africa. Extended abstract, Abstracts Volume, Geocongress ’90 (Cape Town, July 1990), Geological Society of South Africa: 363-366.

  • McMillan, I.K. 1990. A foraminiferal biostratigraphy and chronostratigraphy for the Pliocene to Pleistocene upper Algoa Group, eastern Cape, South Africa. South African Journal of Geology 93 (4): 622-644.

  • McMillan, I.K. 1992. Benthonic and planktonic foraminifera from the Lower Santonian outcrop at Wanderfeld IV, near Bogenfels, southern Namibia. Géologie Africaine, 11th Colloque Africain de Micropaléontologie (Libreville, Gabon, May 1991), Elf-Aquitaine Mémoire 13: 412.

  • McMillan, I.K. 1993. Foraminiferal biostratigraphy, sequence stratigraphy and interpreted chronostratigraphy of marine Quaternary sedimentation on the South African continental shelf. South African Journal of Science 89 (2): 83-89. (SASQUA meeting, Port Elizabeth, 1991).

  • McMillan, I.K. 1997. An Ammonia biostratigraphy for the Neogene and Quaternary marine and aeolian deposits of the South African continental shelf and coastline. Abstract, 13th Colloquium of African Micropalaeontology (Yaoundé, Cameroun, March 1997).

  • McMillan, I.K. 1997. Quaternary sub-surface stratigraphy of the Maputaland coastal plain. In: Botha, G.A. (ed.), Maputaland, Focus on the Quaternary Evolution of the South-East African Coastal Plain, Field Guide and Abstracts (various Kwazulu-Natal venues, April 1997), International Union of Quaternary Research, Commission on Quaternary Shorelines: 70-72.

  • McMillan, I.K. (and other authors?) 1998. Status of Holocene foraminifera studies and taxonomic list of foraminifera recognised along the South African coast and across the continental shelf to upper slope. Taxonomic Database Blue Book for South Africa, FRD Report, Pretoria: pages?

  • McMillan, I.K. 2003. The foraminifera of the Late Valanginian to Hauterivian (Early Cretaceous) Sundays River Formation of the Algoa Basin, Eastern Cape Province, South Africa. Annals of the South African Museum 106: 1-274.

  • McMillan I.K. 2003. Foraminiferally defined biostratigraphic episodes and sedimentation pattern of the Cretaceous drift succession (Early Barremian to Late Maastrichtian) in seven basins on the South African and southern Namibian continental margin. South African Journal of Science 99 (11/12): 537-576.

  • McMillan, I.K., Brink, G.J., Broad, D.S. & Maier, J.J. 1997. Late Mesozoic sedimentary basins off the south coast of South Africa. In: Selley, R.C. (ed.), Sedimentary Basins of the World 3: African Basins. Elsevier, Amsterdam: 319-376.

  • McMillan, I.K. & Stevenson, I.R. 1998. A sedimentation, tectonic and high-resolution stratigraphic history of the Orange Basin, western offshore, South Africa and southern Namibia, based on regional and localised detailed seismic and micropalaeontology studies. Abstract, abstracts volume, South Atlantic Mesozoic Correlations, IGCP Project 381 (Comodoro Rivadavia, Argentina, November 1998). Asociación Paleontológica del Golfo San Jorge, Boletín 2 (Special Edition): 21-23.

  • Ovechkina, M.N., Bylinskaya, M.E. & Uken, R. 2010. Planktonic foraminiferal assemblage in surface sediments from the Thukela Shelf, South Africa. African Invertebrates 51 (2): 231-254. see abstract

  • Pegler, E.A. & McMillan, I.K. 1998. Tectonostratigraphic evolution of the Orange Basin, southwestern Africa. Abstract, Abstracts volume, Gondwana 10: Stratigraphy of Gondwana (Cape Town, 1998), Journal of African Earth Sciences 27 (1A): 147.

  • Rust, I.C., Stear, D.A., Illenberger, W.K., Smuts, W.J. & McMillan, I.K. 1990. The Alexandria coastal dunefield and its hinterland: a model for Pleistocene and Neogene palaeogeography of Algoa Bay. In: Heine, K. (ed.), Palaeoecology of Africa and the Surrounding Islands, A.A. Balkema, Rotterdam, 21: 61-72.

  • Stevenson, I.R. & McMillan, I.K. 2004. Incised valley fill stratigraphy of the Upper Cretaceous succession, proximal Orange Basin, Atlantic margin of southern Africa. Journal of the Geological Society, London 161 (2): 185-208.

  • Toefy, R., Gibbons, M.J. & McMillan, I.K. 2005. The foraminifera associated with the alga Gelidium pristoides, South Africa. African Invertebrates (Natal Museum) 46: 1-26.

  • Toefy, R., McMillan, I.K. & Gibbons, M.J. 2003. The effect of wave exposure on the foraminifera of Gelidium pristoides. Journal of the Marine Biology Association, United Kingdom 83 (4): 705-710.

  • Valicenti, V.H., Benson, J.M., Petrie, H.S.P., Pringle, A.A. & McMillan, I.K. 1992. Correlation of depositional sequence tract boundaries within the Albian 14A sequence, Bredasdorp Basin, South Africa, using condensed sections. Géologie Africaine, 11th Colloque Africain de Micropaléontologie (Libreville, Gabon, May 1991), Elf-Aquitaine Mémoire 13: 414.

  • Wright, C.I., McMillan, I.K. & Mason, T.R. 1990. Foraminifera and sedimentation patterns in St. Lucia estuary mouth, Zululand, South Africa. South African Journal of Geology 93 (4): 592-601.

 

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