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

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<span class="mw-page-title-main">Elliot Formation</span> Lithostratigraphic layer of the Stormberg Group in South Africa

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<span class="mw-page-title-main">Uitenhage Group</span> 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.

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<span class="mw-page-title-main">Buffelskloof Formation</span> 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.

<span class="mw-page-title-main">Teekloof Formation</span> 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.{{cite thesis}}: CS1 maint: multiple names: authors list (link)
  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.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  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. Bibcode:2008Ichno..15..190R. 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. Bibcode:2008Ichno..15..190R. 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.