Angwa Sandstone Formation

Angwa Sandstone Formation
Stratigraphic range: Triassic
~252–210 Ma

Angwa sandstone boulder from Chirundu Hill, Hurungwe District, Zimbabwe
Type Geological formation
Unit of Upper Karoo Group, Karoo Supergroup
Sub-units Alternations Mb.
Chirambakadoma Mb.
Underlies Pebbly Arkose Formation
Overlies Lower Karoo Group
Lithology
Primary Sandstone
Other Siltstone
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, underlying the Pebbly Arkose Formation and overlying 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 Karoo 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
Dadoxylon Mbire District and Chirundu, Zimbabwe
Callistophytaceae (Pteridospermopsida) of the Angwa Sandstone Formation
Taxa Presence Notes Images
Lepidopteris Manyima River, Mbire District, Zimbabwe
Dicroidium Manyima River, Mbire District, Zimbabwe
Ginkgoales of the Angwa Sandstone Formation
Taxa Presence Notes Images
Sphenobaiera Manyima River, Mbire District, Zimbabwe

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. 1 2 3 P. M. Oesterlen; 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. 1 2 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. 1 2 3 4 G. Barale; M. Bamford; B. Gómez; T.J. Broderick; M.A. 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.

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