Angwa Sandstone

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Angwa Sandstone
Stratigraphic range: Triassic
~252–210  Ma
Angwa-sandstone-chirundu.JPG
Angwa sandstone boulder from Chirundu Hill, Hurungwe District, Zimbabwe
Type Geological formation
Unit of Upper Karoo Group, Karoo Supergroup
Sub-unitsAlternations Mb.
Massive Sandstone Mb. [1]
Underlies Pebbly Arkose Formation
Overlies Lower Karoo Group
Lithology
Primary Sandstone
Other Siltstone
Location
Coordinates 16°06′25″S30°18′25″E / 16.107°S 30.307°E / -16.107; 30.307 [1]
CountryFlag of Mozambique.svg  Mozambique
Flag of Zambia.svg  Zambia
Flag of Zimbabwe.svg  Zimbabwe
Type section
Named for Angwa River, Zimbabwe
Named byP.M. Oesterlen, Zimbabwe Geological Survey [2]
Zimbabwe relief location map.jpg
Pink ff0080 pog.svg
Angwa Sandstone (Zimbabwe)

The Angwa Sandstone is a geological formation of the mid-Triassic Cabora Bassa Basin [1] and Mana Pools Basin [3] of southern Africa, consisting mainly of sandstone. [4]

Contents

Description

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. [1]

The Angwa Sandstone has been correlated to the Molteno Formation of the Great Karoo Basin, South Africa, [6] [1] and to the Escarpment Grit of the Mid-Zambezi Basin. [7]

Lithology

The formation is a sedimentary unit, consisting mainly of fluvial sands and silts. [1]

It has been dated as covering rocks from much of the Triassic, with pollen and flora identified from the Induan, and Ladinian to Norian. [6] [8]

Occurrence

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

Fossil Content

Pinales of the Angwa Sandstone
GenusPresenceNotesImages
Dadoxylon Mbire District and Chirundu, Zimbabwe
Callistophytaceae (Pteridospermopsida) of the Angwa Sandstone
GenusPresenceNotesImages
Lepidopteris Manyima River, Mbire District, Zimbabwe
[8]
Dicroidium Manyima River, Mbire District, Zimbabwe
[8]
Ginkgoales of the Angwa Sandstone
GenusPresenceNotesImages
Sphenobaiera Manyima River, Mbire District, Zimbabwe
[8]

Related Research Articles

<span class="mw-page-title-main">Karoo Supergroup</span> 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.

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

<i>Daptocephalus</i> Assemblage Zone

The Daptocephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the upper Teekloof Formation west of 24°E, the majority of the Balfour Formation east of 24°E, and the Normandien Formation in the north. It has numerous localities which are spread out from Colesberg in the Northern Cape, Graaff-Reniet to Mthatha in the Eastern Cape, and from Bloemfontein to Harrismith in the Free State. The Daptocephalus Assemblage Zone is one of eight biozones found in the Beaufort Group and is considered Late Permian (Lopingian) in age. Its contact with the overlying Lystrosaurus Assemblage Zone marks the Permian-Triassic boundary.

<i>Lystrosaurus</i> Assemblage Zone

The Lystrosaurus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Adelaide and lower Tarkastad Subgroups of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. This biozone has outcrops in the south central Eastern Cape and in the southern and northeastern Free State. The Lystrosaurus Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Early Triassic in age.

<span class="mw-page-title-main">Ecca Group</span> Second of the main subdivisions of the Karoo Supergroup of geological strata in southern Africa

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

<span class="mw-page-title-main">Forest Sandstone</span> Geologic formation in Southern Africa

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<span class="mw-page-title-main">Batoka Formation</span> Geological formation in Southern Africa

The Batoka Formation is a geological formation in the Zambezi valley in Botswana, Zambia and Zimbabwe. It is predominantly a volcanic unit comprising mainly basalts. It was formerly thought to contain sand stones containing the dinosaur Vulcanodon, however this was shown to be in error resulting from interpreting folding of the rocks as separate layers, with the sandstone layers actually being from the underlying Forest Sandstone.

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

<span class="mw-page-title-main">Pebbly Arkose Formation</span>

The Pebbly Arkose Formation is a Late Triassic geologic formation found in southern Africa.

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

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

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

The Escarpment Grit is a Triassic geologic formation. It is also referred to as the Nyoka Grit.

<span class="mw-page-title-main">Upper Karoo Group</span> Sequence of Triassic to Early Jurassic rocks in southern Africa

The Upper Karoo Group is a sequence of Triassic to Early Jurassic sedimentary and volcanic rocks found in Botswana, Zambia, and Zimbabwe.

<i>Agathoxylon</i> Extinct genus of conifers of the family Araucariaceae

Agathoxylon is a form genus of fossil wood, including massive tree trunks. Although identified from the late Palaeozoic to the end of the Mesozoic, Agathoxylon is common from the Carboniferous to Triassic. Agathoxylon represents the wood of multiple conifer groups, including both Araucariaceae and Cheirolepidiaceae, with late Paleozoic and Triassic forms possibly representing other conifers or other seed plant groups like "pteridosperms".

<span class="mw-page-title-main">Lower Karoo Group</span>

The Lower Karoo Group is a sequence of late Carboniferous and Permian sandstone sedimentary rocks of the Karoo Supergroup, found in Botswana, Zambia, Zimbabwe, and Mozambique.

<span class="mw-page-title-main">Balfour Formation</span> 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 - Early Triassic 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.

<span class="mw-page-title-main">Katberg Formation</span> Geological formation in the Beaufort Group of the Karoo Supergroup in South Africa

The Katberg 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 Katberg Formation is the lowermost geological formation of the Tarkastad Subgroup which contains the Lower to Middle Triassic-aged rocks of the Beaufort Group. Outcrops and exposures of the Katberg Formation are found east of 24 degrees on wards and north of Graaff-Reniet, Nieu Bethesda, Cradock, Fort Beaufort, Queensdown, and East London in the south, and ranges as far north as Harrismith in deposits that form a ring around the Drakensberg mountain ranges.

<span class="mw-page-title-main">Middleton Formation</span> Late middle Permian geological formation in the Eastern Cape

The Middleton Formation is a geological formation that extends through the Northern Cape, Western Cape, and Eastern Cape provinces of South Africa. It overlies the lower Abrahamskraal Formation, and is the eastern correlate, East of 24ºE, of the Teekloof Formation. Outcrops and exposures of the Middleton Formation range from Graaff-Reinet in the Eastern Cape onwards. The Middleton Formation's type locality lies near the small hamlet, Middleton, approximately 25 km south of Cookhouse. Other exposures lie in hillsides along the Great Fish River in the Eastern Cape. The Middleton Formation forms part of the Adelaide Subgroup of the Beaufort Group, which itself forms part of the Karoo Supergroup.

References

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  2. 1 2 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.
  3. Oesterlem, P.M. (2001). "New geological results from the Mana Pools basin of Zimbabwe, Lower Zambezi Graben". Annals of the Zimbabwe Geological Survey. 16: 17–26. Retrieved 15 January 2024.
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  7. 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 (1–3): 211–253. Bibcode:2005JAfES..43..211C. doi:10.1016/j.jafrearsci.2005.07.007.
  8. 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.
  9. D. Love (1997). "The geology of the Chirundu area, Zambezi Valley". Annals of the Zimbabwe Geological Survey. 18: 18–26.