Earth:Pebbly Arkose Formation

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Pebbly Arkose
Stratigraphic range: Carnian
~235–222 Ma
Pebbly-arkose-kariba.png
Pebbly arkose outcrop, Ndepa hill, Kariba District, Zimbabwe
TypeGeological formation
Unit ofUpper Karoo Group, Karoo Supergroup
UnderliesForest Sandstone
OverliesEscarpment Grit & Angwa Sandstone
Lithology
PrimarySandstone
Location
Coordinates [ ⚑ ] : 16°12′S 30°18′E / 16.2°S 30.3°E / -16.2; 30.3
Paleocoordinates [ ⚑ ] 50°48′S 11°54′E / 50.8°S 11.9°E / -50.8; 11.9
RegionMashonaland Central & West
Country Botswana
 Zambia
 Zimbabwe
Type section
Named forDescriptive name
Named byA.M. MacGregor, Zimbabwe Geological Survey
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The Pebbly Arkose Formation is a Late Triassic geologic formation found in southern Africa.

Geology

Description

The formation comprises mainly coarse, arkosic sandstones.[1]

Extent

The Pebbly Arkose Formation is found in Botswana, Zambia and Zimbabwe, in the Mid-Zambezi, Mana Pools, Cabora Bassa and Limpopo basins.

Deposition

Age

Stratigraphy

The Pebbly Arkose Formation is part of the Upper Karoo Group, overlies the Escarpment formation (in the Mid-Zambezi and Limpopo basins)[2] and the Angwa Sandstone Formation (in the Mana Pools and Cabora Bassa Basins)[3] and underlies the Forest Sandstone Formation.[4]

The Pebbly Arkose has been correlated to the Elliot Formation of the Great Karroo Basin, South Africa[4][5] and the Mpandi Formation of the Thuli Basin in Botswana and Zimbabwe.[6]

Fossil content

Flora

Pinales of the Pebbly Arkose Formation
Taxa Presence Notes Images
Form genus: Dadoxylon Widespread in the formation[7]

Vertebrate fauna

Archosauria of the Pebbly Arkose Formation
Genus Presence Notes Images
Mbiresaurus[8] An early member of Sauropodomorpha.
Unnamed aetosaur[8]
Unnamed herrerasaurid[8]
Rhynchosauria of the Pebbly Arkose Formation
Genus Presence Notes Images
Hyperodapedon[9] Dande, Mbire District, Zimbabwe[9]
Hyperodapedon BW2.jpg
Synapsida of the Pebbly Arkose Formation
Genus Presence Notes Images
Possible dicynodont[8]
Unnamed gomphodontosuchine traversodontid cynodont[8]

See also

  • List of dinosaur-bearing rock formations
    • List of stratigraphic units with indeterminate dinosaur fossils
  • List of fossiliferous stratigraphic units in Zimbabwe
  • Geology of Zimbabwe
  • Molteno Formation

References

  1. Love, David; Ravengai, S.; Katemaunzanga, D.; Shoko, D.S.M.; Kambewa, C.; Matura, N.E. (July 2004). "The Karoo sequence in the Nyaminyami area, Zambezi Valley, Zimbabwe". Johannesburg, South Africa: Geological Society of South Africa. p. 135. 
  2. Bordy, Emese M.; Catuneanu, Octavian (2001). "Sedimentology of the upper Karoo fluvial strata in the Tuli Basin, South Africa". Journal of African Earth Sciences 33 (3–4): 605. doi:10.1016/S0899-5362(01)00090-2. Bibcode2001JAfES..33..605B. 
  3. d'Engelbronner, E.R. (1996). "New palynological data from Karoo sediments, Mana Pools basin, northern Zimbabwe". Journal of African Earth Sciences 23: 17. doi:10.1016/S0899-5362(96)00049-8. Bibcode1996JAfES..23...17D. 
  4. 4.0 4.1 Nyambe, Imasiku A.; Utting, John (1997). "Stratigraphy and palynostratigraphy, Karoo Supergroup (Permian and Triassic), mid-Zambezi Valley, southern Zambia". Journal of African Earth Sciences 24 (4): 563. doi:10.1016/S0899-5362(97)00081-X. Bibcode1997JAfES..24..563N. 
  5. 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. doi:10.1016/j.jafrearsci.2005.07.007. Bibcode2005JAfES..43..211C. 
  6. Rogers, Raymond R.; Rogers, Kristina Curry; Munyikwa, Darlington; Terry, Rebecca C.; Bradley s.Singer (2004). "Sedimentology and taphonomy of the upper Karoo-equivalent Mpandi Formation in the Tuli Basin of Zimbabwe, with a new 40Ar/39Ar age for the Tuli basalts". Journal of African Earth Sciences 40 (3–4): 147. doi:10.1016/j.jafrearsci.2004.11.004. Bibcode2004JAfES..40..147R. 
  7. Nugent, Chris (1990). "The Zambezi River: Tectonism, climatic change and drainage evolution". Palaeogeography, Palaeoclimatology, Palaeoecology 78: 55. doi:10.1016/0031-0182(90)90204-K. Bibcode1990PPP....78...55N. 
  8. 8.0 8.1 8.2 8.3 8.4 "Africa's oldest dinosaurs reveal early suppression of dinosaur distribution". Nature 609 (7926): 313–319. 2022. doi:10.1038/s41586-022-05133-x. 
  9. 9.0 9.1 "First record of Triassic Rhynchosauria (Reptilia: Diapsida) from the lower Zambezi Valley, Zimbabwe". Palaentologia Africana 29: 1–10.. 1992. 

Bibliography