Algoa Group

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Algoa Group
Stratigraphic range: Middle Eocene-Holocene
~41–0  Ma
Type Geologic group
Sub-units Bathurst Formation, Alexandria Formation, Nanaga Formation, Salnova Formation, Nahoon Formation, Schelm Hoek Formation
Overlies Table Mountain Group or Uitenhage Group
Lithology
Primary Sandstone, calcareous sandstone, limestone, coquina & conglomerates
Other Calcite
Location
CountryFlag of South Africa.svg  South Africa
Type section
Named forAlgoa area

The Algoa Group is one of five geological groups which comprise the coastal Cenozoic geological deposits in South Africa. The Algoa Group contains six formations which range from Middle Eocene to Late Holocene in age (~41Ma - 100Ka). [1] [2] [3]

Contents

Geographic extent

The geological successions of the Algoa Group outcrop from Plettenberg Bay in the Western Cape to East London in the Eastern Cape of South Africa. There are also putative outcrops of Algoa Group rocks further NE in the Port St Johns area. The Algoa Group rocks overlie unconformably and parauncomformably in some areas over much older rocks of the Table Mountain Group in the west and over the Uitenhage Group in the east. [4] [5] [6]

Stratigraphic units

Stratigraphic units in this group include (from oldest to youngest):

Paleontology and archaeology

Fossils are more frequently found in the older formations, although the Alexandria and Salnova formations are the most fossil rich. The most common fossils are of invertebrates, namely of marine gastropods and bivalves, and trace fossils left such as of burrows left by invertebrates. Vertebrate trackways of birds and modern humans are known from the Nahoon Formation. [18]

The Nahoon and Schelm Hoek Formations are known for their archeological artefacts, including modern human trackways in the case of the Nahoon Formation. Both these formations have yielded stone tools. Shell middens and evidence of for small, coastal human settlements are known from the Schelm Hoek Formation. [19] [20] [21]

Related Research Articles

Karoo Supergroup Widespread Mesozoic stratigraphic unit in southern Africa

The Karoo Supergroup is the most widespread stratigraphic unit in Africa south of the Kalahari Desert. The supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Late Carboniferous and Early Jurassic, a period of about 120 million years.

Beaufort Group Third of the main subdivisions of the Karoo Supergroup in South Africa

The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper Tarkastad Subgroup. It follows conformably after the Ecca Group and unconformably underlies the Stormberg Group. Based on stratigraphic position, lithostratigraphic and biostratigraphic correlations, palynological analyses, and other means of geological dating, the Beaufort Group rocks are considered to range between Middle Permian (Wordian) to Early Triassic (Anisian) in age.

Fossil track Fossilized footprint (ichnite)

A fossil track or ichnite is a fossilized footprint. This is a type of trace fossil. A fossil trackway is a sequence of fossil tracks left by a single organism. Over the years, many ichnites have been found, around the world, giving important clues about the behaviour of the animals that made them. For instance, multiple ichnites of a single species, close together, suggest 'herd' or 'pack' behaviour of that species.

<i>Tropidostoma</i> Assemblage Zone

The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.

<i>Eodicynodon</i> Assemblage Zone

The Eodicynodon Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 620 metres (2,030 ft), occur south-east of Sutherland, north of Prince Albert, and south-east of Beaufort West. The Eodicynodon Assemblage Zone is the lowermost biozone of the Beaufort Group.

Ecca Group Second of the main subdivisions of the Karoo Supergroup of geological strata in southern Africa

The Ecca Group is the second of the main subdivisions of the Karoo Supergroup of geological strata in southern Africa. It mainly follows conformably after the Dwyka Group in some sections, but in some localities overlying unconformably over much older basement rocks. It underlies the Beaufort Group in all known outcrops and exposures. Based on stratigraphic position, lithostratigraphic correlation, palynological analyses, and other means of geological dating, the Ecca Group ranges between Early to earliest Middle Permian in age.

Clarens Formation Geological formation of the Stormberg Group in southern Africa

The Clarens Formation is a geological formation found in several localities in Lesotho and in the Free State, KwaZulu-Natal, and Eastern Cape provinces in South Africa. It is the uppermost of the three formations found in the Stormberg Group of the greater Karoo Supergroup rocks and represents the final phase of preserved sedimentation of the Karoo Basin.

Elliot Formation Lithostratigraphic layer of the Stormberg Group in South Africa

The Elliot Formation is a geological formation and forms part of the Stormberg Group, the uppermost geological group that comprises the greater Karoo Supergroup. Outcrops of the Elliot Formation have been found in the northern Eastern Cape, southern Free State, and in the eastern KwaZulu-Natal provinces of South Africa. Outcrops and exposures are also found in several localities in Lesotho such as Qacha's Neck, Hill Top, Quthing, and near the capital, Maseru. The Elliot Formation is further divided into the lower (LEF) and upper (UEF) Elliot formations to differentiate significant sedimentological differences between these layers. The LEF is dominantly Late Triassic (Norian-Hettangian) in age while the UEF is mainly Early Jurassic (Sinemurian-Pliensbachian) and is tentatively regarded to preserve a continental record of the Triassic-Jurassic boundary in southern Africa. This geological formation is named after the town of Elliot in the Eastern Cape, and its stratotype locality is located on the Barkly Pass, 9 km north of the town.

Kirkwood Formation Cretaceous geological formation in the Uitenhage Group

The Kirkwood Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is one of the four formations found within the Uitenhage Group of the Algoa Basin – its type locality – and in the neighbouring Gamtoos Basin. Outcrops of the Kirkwood are also found along the Worcester-Pletmos, Herbertsdale-Riversdale, Heidelberg-Mossel Bay, and Oudtshoorn-Gamtoos basin lines. At these basins the Kirkwood Formation underlies the Buffelskloof Formation and not the Sundays River Formation.

Molteno Formation Triassic geological formation in the Stormberg Group in Lesotho and South Africa

The Molteno Formation is a geological formation found in several localities in Lesotho and South Africa. It lies mainly south of Maseru, near Burgersdorp, Aliwal North, Dordrecht, Molteno, and Elliot. It extends as far north as Matatiele in the Eastern Cape. The formation's localities lie along the Drakensberg Mountains in Kwazulu-Natal, and near Ladybrand in the Free State of South Africa. The Molteno Formation is the lowermost of the three formations in the Stormberg Group of the greater Karoo Supergroup. The Molteno Formation represents the initial phase of preserved sedimentation of the Stormberg Group.

Enon Formation Jurassic-Cretaceous geological formation in the Uitenhage Group of South Africa

The Enon Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is the lowermost of the four formations found within the Uitenhage Group of the Algoa Basin, its type locality, where it has been measured at a maximum thickness of 480 metres (1,570 ft). Discontinuous outcrops are also found in the Worcester-Pletmos and Oudshoorn-Gamtoos Basins, including isolated occurrences in the Haasvlakte, Jubilee, and Soutpansvlakte Basins near the small town Bredasdorp.

Sundays River Formation Geological formation in the Uitenhage Group of the Algoa Basin in South Africa

The Sundays River Formation is a geological formation found in the Eastern and Western Cape provinces in South Africa. It is the second youngest of the four formations found within the Uitenhage Group of the Algoa Basin, its type locality, and the only location where outcrops have been located. The Sundays River has been measured at a maximum thickness of 2,000 metres (6,600 ft).

Stormberg Group Triassic/Jurassic geological group in the Karoo Supergroup in South Africa

The Stormberg Group is one of the four geological groups that comprises the Karoo Supergroup in South Africa. It is the uppermost geological group representing the final phase of preserved sedimentation of the Karoo Basin. The Stormberg Group rocks are considered to range between Lower Triassic (Olenekian) to Lower Jurassic (Pliensbachian) in age. These estimates are based on means of geological dating including stratigraphic position, lithostratigraphic and biostratigraphic correlations, and palynological analyses.

Dwyka Group Geological group in the Karoo Supergroup from South Africa

The Dwyka Group is one of four geological groups that compose the Karoo Supergroup. It is the lowermost geological group and heralds the commencement of sedimentation of the Karoo Supergroup. Based on stratigraphic position, lithostratigraphic correlation and palynological analyses, these lowermost Karoo strata range between the Late Carboniferous (Pennsylvanian) to Early Permian in age.

Abrahamskraal Formation Geological formation of the Beaufort Group in South Africa

The Abrahamskraal Formation is a geological formation and is found in numerous localities in the Northern Cape, Western Cape, and the Eastern Cape of South Africa. It is the lowermost formation of the Adelaide Subgroup of the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup. It represents the first fully terrestrial geological deposits of the Karoo Basin. Outcrops of the Abrahamskraal Formation are found from the small town Middelpos in its westernmost localities, then around Sutherland, the Moordenaarskaroo north of Laingsburg, Williston, Fraserburg, Leeu-Gamka, Loxton, and Victoria West in the Western Cape and Northern Cape. In the Eastern Cape outcrops are known from Rietbron, north of Klipplaat and Grahamstown, and also southwest of East London.

Uitenhage Group Geological group of post-Karoo Mesozoic rocks in South Africa

The Uitenhage Group is one of three geological groups, which comprise the onshore and offshore post-Karoo middle to lower Upper Mesozoic geological rock units in South Africa. Stratigraphically, the Uitenhage Group overlies the Suurberg Group and is overlain by the Algoa Group. It contains four formations that range in age from late Early Jurassic and late Early Cretaceous in age.

Bokkeveld Group Devonian sedimentary rocks in South Africa

The Bokkeveld Group is the second of the three main subdivisions of the Cape Supergroup in South Africa. It overlies the Table Mountain Group and underlies the Witteberg Group. The Bokkeveld Group rocks are considered to range between Lower Devonian (Lochkovian) to Middle Devonian (Givetian) in age.

Buffelskloof Formation Geological formation in the Uitenhage Group of the Algoa Basin in South Africa

The Buffelskloof Formation is a geological formation found in the Western Cape province in South Africa. It is the uppermost of the four formations found within the Uitenhage Group of the Algoa Basin. It is considered an informal formation by some of the literature as it is very thin and only outcrops as isolated horizons in the Oudshoorn-Gamtoos, Herbertsdale-Mossel Bay, and Heidelberg-Riversdale Basins. Along the Worcester-Pletmos Basin, it occurs in patches along the southern flanks of the Langeberg mountain range - from Worcester in the west and as far as Mossel Bay in the east. From Mossel Bay this formation is inter fingered by the informal Hartenbos Formation. The Buffelskloof and Hartenbos Formations only occur in the Oudshoorn-Gamtoos and Herbertsdale-Mossel Bay basins and seem to correlate to the Sundays River Formation in age.

Balfour Formation Geological formation in the Beaufort Group of South Africa

The Balfour Formation is a geological formation that is found in the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup in South Africa. The Balfour Formation is the uppermost formation of the Adelaide Subgroup which contains all the Late Permian-aged biozones of the Beaufort Group. Outcrops and exposures of the Balfour Formation are found from east of 24 degrees in the highest mountainous escarpments between Beaufort West and Fraserburg, but most notably in the Winterberg and Sneeuberg mountain ranges near Cradock, the Baviaanskloof river valley, Graaff-Reniet and Nieu Bethesda in the Eastern Cape, and in the southern Free State province.

Teekloof Formation Late Permian geological formation that forms part of the Beaufort Group of South Africa

The Teekloof Formation is a geological formation that forms part of the Beaufort Group, one of the five geological groups that comprises the Karoo Supergroup in South Africa. The Teekloof Formation is the uppermost formation of Adelaide Subgroup deposits West of 24ºE and contains Middle to Late Permian-aged deposits and four biozones of the Beaufort Group. It overlies the Abrahamskraal Formation. The Teekloof Formation does not underlie other units other than the younger Karoo dolerites and sills that relate to the emplacement of the Early Jurassic Drakensberg Group to the east. Outcrops and exposures of the Teekloof Formation range from Sutherland through the mountain escarpments between Fraserburg and Beaufort West. The northernmost localities of the Teekloof Formation are found by Loxton, Victoria West and Richmond.

References

  1. Roberts, D. L., Botha, G. A., Maud, R. R., Pether, J., and Johnson, M. R. (2006). Coastal cenozoic deposits. The geology of South Africa. Johannesburg/Pretoria: Geological Society of South Africa/Council for Geoscience, 605-628.
  2. Dingle, R.V., Siesser, W.G. and Newton, A.R., 1983. Mesozoic and Tertiary geology of southern Africa. Rotterdam: Balkema.
  3. Partridge, R.R., 1987. Geomorphic evolution of southern Africa since the Mesozoic. South African Journal of Geology, 90(2), pp.179-208.
  4. Roberts, D.L., Botha, G.A., Maud, R.R., Pether, J. and Johnson, M.R., 2006. Coastal cenozoic deposits. The geology of South Africa. Johannesburg/Pretoria: Geological Society of South Africa/Council for Geoscience, pp.605-628.
  5. Roux, F. G. Le (1990-07-01). "Palaeontological correlation of Cenozoic marine deposits of the southeastern, southern and western coasts, Cape Province". South African Journal of Geology. 93 (3). ISSN   1012-0750.
  6. G., Le Roux, F. (August 1989). The lithostratigraphy of Cenozoic deposits along the south-east Cape coast as related to sea-level changes (Thesis). Stellenbosch : Stellenbosch University.
  7. Siesser, W. G. Maud, R. R., Partridge, T. C. & (1987-09-01). "An Early Tertiary marine deposit at Pato's Kop, Ciskei". South African Journal of Geology. 90 (3). ISSN   1012-0750.
  8. Almond, J.E., 2012. Proposed prospecting for and mining of fossiliferous marine limestone of Eocene age near Bathurst, Bathurst District, Eastern Cape. Link: http://www.sahra.org.za/sahris/sites/default/files/heritagereports/PIA-Laman%20Lime%20Prospecting,%20Bathurst,%20EC%202012%20%5B1%5D.pdf
  9. King, L. (1972-05-01). "Pliocene marine fossils from the Alexandria Formation in the Paterson District, Eastern Cape Province, and their geomorphic significance". South African Journal of Geology. 75 (2). ISSN   1012-0750.
  10. McMillan, I. K. (1990-08-01). "A foraminiferal biostratigraphy and chronostratigraphy for the Pliocene to Pleistocene Upper Algoa Group, eastern Cape, South Africa". South African Journal of Geology. 93 (4). ISSN   1012-0750.
  11. Le Roux, F.G., 1988. The Alexandria, Nanaga and Salnova Formations redefined and their stratigraphic positions in the Algoa Group. Geoconl {ress' 88. Ext. Abstr. 22nd Earth Science Conl {ress, Geo/. Soc. S. Afr, pp.363-366.
  12. Le Roux, F.G., 1989. Lithostratigraphy of the Nahoon Formation (Algoa Group) (No. 9). Republic of South Africa, Department of Mineral and Energy Affairs, Geological Survey.
  13. Partridge, T.C., Avery, D.M., Botha, G.A., Brink, J.S., Deacon, J., Herbert, R.S., Maud, R.R., Scholtz, A., Scott, L., Talma, A.S. and Vogel, J.C., 1990. Late pleistocene and holocene climatic-change in Southern Africa. South African Journal of Science, 86(7-10), pp.302-306.
  14. Roberts, David L. (2008-12-03). "Last Interglacial Hominid and Associated Vertebrate Fossil Trackways in Coastal Eolianites, South Africa". Ichnos. 15 (3–4): 190–207. doi:10.1080/10420940802470482. ISSN   1042-0940.
  15. Roberts, D. L., Botha, G. A., Maud, R. R., Pether, J., and Johnson, M. R. (2006). Coastal cenozoic deposits. The geology of South Africa. Johannesburg/Pretoria: Geological Society of South Africa/Council for Geoscience, 605-628.
  16. J. E. Almond (March, 2010) Coega IDZ Fossil Heritage PIA Part2 Natura Viva cc 41 3.3. ALGOA GROUP. Link: http://www.sahra.org.za/sahris/sites/default/files/heritagereports/Coega%20IDZ%20Fossil%20Heritage%20PIA%20Part2.pdf
  17. Illenberger, W.K., 1992. Lithostratigraphy of the Schelm Hoek formation(Algoa group). Lithostratigraphic series.
  18. Roberts, David L. (2008-12-03). "Last Interglacial Hominid and Associated Vertebrate Fossil Trackways in Coastal Eolianites, South Africa". Ichnos. 15 (3–4): 190–207. doi:10.1080/10420940802470482. ISSN   1042-0940.
  19. Roberts, D. L., Botha, G. A., Maud, R. R., Pether, J., and Johnson, M. R. (2006). Coastal cenozoic deposits. The geology of South Africa. Johannesburg/Pretoria: Geological Society of South Africa/Council for Geoscience, 605-628.
  20. J. E. Almond (March, 2010) Coega IDZ Fossil Heritage PIA Part2 Natura Viva cc 41 3.3. ALGOA GROUP. Link: http://www.sahra.org.za/sahris/sites/default/files/heritagereports/Coega%20IDZ%20Fossil%20Heritage%20PIA%20Part2.pdf
  21. Partridge, T.C., Avery, D.M., Botha, G.A., Brink, J.S., Deacon, J., Herbert, R.S., Maud, R.R., Scholtz, A., Scott, L., Talma, A.S. and Vogel, J.C., 1990. Late pleistocene and holocene climatic-change in Southern Africa. South African Journal of Science, 86(7-10), pp.302-306.