Angwa Sandstone Formation

Angwa Sandstone Formation
Stratigraphic range: Middle Triassic

Angwa sandstone boulder from Chirundu hill, Hurungwe District, Zimbabwe
Type Geological formation
Unit of Upper Karoo Group, Karoo Supergroup
Underlies Pebbly Arkose Formation
Overlies Lower Karoo Group
Location
Country Mozambique, Zambia, Zimbabwe
Type section
Named for Angwa River, Zimbabwe

The Angwa Sandstone Formation is a geological formation of the mid-Triassic, consisting mainly of sandstone.[1]

Geology

The formation is a sedimentary unit, consisting mainly of fluvial sands and silts.[2]

It has been dated as covering rocks from much of the Triassic, with pollen and flora identified from the Induan, and Ladinian to Norian.[3][4]

Stratigraphy

The Angwa Sandstone is the lowest formation in the Upper Karoo Group of the Karoo Supergroup, lying below the Pebbly Arkose Formation and overlting the Lower Karoo Group.[5] The formation is divided into two members: the Alternations Member and the Massive Sandstone (Chirambakadoma) Member.[2]

The Angwa Sandstone has been correlated to the Molteno Formation of the Great Karroo Basin, South Africa[3][2] and to the Escarpment Grit of the Mid-Zambezi Basin.[6]

Occurrence

The Angwa Sandstone Formation is found in Mozambique, Zambia, Zimbabwe, in the Mana Pools and Cabora Bassa basins.

Flora

Pinales of the Angwa Sandstone Formation
Taxa Presence Notes Images

Form genus: Dadoxylon

 Mbire District[7] and Chirundu, Zimbabwe[8]
Callistophytaceae (Pteridospermopsida) of the Angwa Sandstone Formation
Taxa Presence Notes Images
Genus: Lepidopteris Manyima River, Mbire District, Zimbabwe[4]
Genus: Dicroidium Manyima River, Mbire District, Zimbabwe[4]
Ginkgoales of the Angwa Sandstone Formation
Taxa Presence Notes Images
Genus: Sphenobaiera Manyima River, Mbire District, Zimbabwe[4]

References

  1. ↑ Moore, A.E.; Cotterill, F.P.D.; Broderick, T.; Plowes, D. (2009). "Landscape evolution in Zimbabwe from the Permian to present, with implications for kimberlite prospecting". South African Journal of Geology 112: 65. doi:10.2113/gssajg.112.1.65.
  2. ↑ 2.0 2.1 2.2 P. M. Oesterlen and B. D. Millsteed (1994). "Lithostratigraphy, palaeontology, and sedimentary environments of the western Cabora Bassa Basin, lower Zambezi Valley, Zimbabwe". South African Journal of Geology 97: 205–224.
  3. ↑ 3.0 3.1 d'Engelbronner, E.R. (1996). "New palynological data from Karoo sediments, Mana Pools basin, northern Zimbabwe". Journal of African Earth Sciences 23: 17. Bibcode:1996JAfES..23...17D. doi:10.1016/S0899-5362(96)00049-8.
  4. ↑ 4.0 4.1 4.2 4.3 G Barale, M Bamford, B Gomez, TJ Broderick, MA Raath, A Cadman (2005). "A fossil peat deposit from the Late Triassic (Carnian) of Zimbabwe with preserved cuticle of Pteridospermopsida and Ginkgoales, and its geological setting". Palaeontologia Africana 41: 89–100.
  5. ↑ Oesterlen, P.M.; Blenkinsop, T.G. (1994). "Extension directions and strain near the failed triple junction of the Zambezi and Luangwa Rift zones, southern Africa". Journal of African Earth Sciences 18 (2): 175. Bibcode:1994JAfES..18..175O. doi:10.1016/0899-5362(94)90029-9.
  6. ↑ 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. Bibcode:2005JAfES..43..211C. doi:10.1016/j.jafrearsci.2005.07.007.
  7. ↑ P.M. Oesterlen (1990). "The geology of the Dande West area (western Cabora Bassa Basin) - a preliminary report". Annals of the Zimbabwe Geological Survey 14: 12–20.
  8. ↑ D. Love (1997). "The geology of the Chirundu area, Zambezi Valley". Annals of the Zimbabwe Geological Survey 18: 18–26.