Earth:Escarpment Grit
| Escarpment Grit Stratigraphic range: Early Triassic | |
|---|---|
| Type | Geological formation |
| Unit of | Upper Karoo Group, Karoo Supergroup |
| Underlies | Pebbly Arkose Formation |
| Overlies | Lower Karoo Group |
| Lithology | |
| Primary | Gritstone |
| Other | Sandstone |
| Location | |
| Country |  Zambia Zimbabwe |
| Type section | |
| Named for | Descriptive name |
| Named by | A.M. MacGregor, Zimbabwe Geological Survey |
The Escarpment Grit is a Triassic geologic formation.[1] It is also referred to as the Nyoka Grit.[2]
Geology
The formation is composed of fluvial sediments, mainly gritstones and coarse sandstones.[3] Uranium is present in the Escarpment Grit of southern Zambia.[4]
Stratigraphy
The Escarpment Grit Formation is the basal unit of the Upper Karoo Group[5] and underlies the Pebbly Arkose Formation.[6] It has been dated as Upper Scythian (Early Triassic).[7]
The Pebbly Arkose has been correlated to the Angwa Sandstone Formation in the Mana Pools and Cabora Bassa Basins,[8] and the Elliot Formation of the Great Karoo Basin, South Africa.[6][7]
Flora
Alisporites spores have been identified from the Escarpment Grit in north-western Zimbabwe.[8]
Hydrogeology
This formation constitutes a productive aquifer in north-western Zimbabwe, although of limited thickness.[9]
References
- ↑ Nyambe, Imasiku A. (1999). "Tectonic and climatic controls on sedimentation during deposition of the Sinakumbe group and Karoo supergroup, in the mid-Zambezi Valley Basin, southern Zambia". Journal of African Earth Sciences 28 (2): 443–463. doi:10.1016/S0899-5362(99)00014-7. Bibcode: 1999JAfES..28..443N.
- ↑ Kreuser, T; Wopfner, H; Kaaya, C; Markwort, S; Semkiwa, P; Aslandis, P (1990). "Depositional evolution of permo-triassic karoo basins in Tanzania with reference to their economic potential". Journal of African Earth Sciences 10 (1–2): 151–167. doi:10.1016/0899-5362(90)90052-G. Bibcode: 1990JAfES..10..151K.
- ↑ Nyambe, Imasiku A.; Dixon, Owen (2000). "Sedimentology of the Madumabisa Mudstone Formation (Late Permian), Lower Karoo Group, mid-Zambezi Valley Basin, southern Zambia". Journal of African Earth Sciences 30 (3): 535. doi:10.1016/S0899-5362(00)00037-3. Bibcode: 2000JAfES..30..535N.
- ↑ Sikatali, C; Njamu, M (1992). "A uranium orientation survey in Sikaneka area, Southern Zambia". Journal of African Earth Sciences 14 (2): 275. doi:10.1016/0899-5362(92)90104-K. Bibcode: 1992JAfES..14..275S.
- ↑ 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. Bibcode: 2001JAfES..33..605B.
- ↑ 6.0 6.1 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. Bibcode: 1997JAfES..24..563N.
- ↑ 7.0 7.1 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. doi:10.1016/j.jafrearsci.2005.07.007. Bibcode: 2005JAfES..43..211C.
- ↑ 8.0 8.1 d'Engelbronner, E.R. (1996). "New palynological data from Karoo sediments, Mana Pools basin, northern Zimbabwe". Journal of African Earth Sciences 23 (1): 17–30. doi:10.1016/S0899-5362(96)00049-8. Bibcode: 1996JAfES..23...17D.
- ↑ Danielsen, Jens E.; Dahlin, Torleif; Owen, Richard; Mangeya, Pride; Auken, Esben (2007). "Geophysical and hydrogeologic investigation of groundwater in the Karoo stratigraphic sequence at Sawmills in northern Matabeleland, Zimbabwe: A case history". Hydrogeology Journal 15 (5): 945. doi:10.1007/s10040-007-0191-z. Bibcode: 2007HydJ...15..945D. http://portal.research.lu.se/ws/files/2951758/4934450.pdf.
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