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 |
| 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 Karroo 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. Bibcode:1999JAfES..28..443N. doi:10.1016/S0899-5362(99)00014-7.
- ↑ 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: 151. Bibcode:1990JAfES..10..151K. doi:10.1016/0899-5362(90)90052-G.
- ↑ 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. Bibcode:2000JAfES..30..535N. doi:10.1016/S0899-5362(00)00037-3.
- ↑ Sikatali, C; Njamu, M (1992). "A uranium orientation survey in Sikaneka area, Southern Zambia". Journal of African Earth Sciences. 14 (2): 275. Bibcode:1992JAfES..14..275S. doi:10.1016/0899-5362(92)90104-K.
- ↑ 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. Bibcode:2001JAfES..33..605B. doi:10.1016/S0899-5362(01)00090-2.
- 1 2 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. Bibcode:1997JAfES..24..563N. doi:10.1016/S0899-5362(97)00081-X.
- 1 2 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.
- 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.
- ↑ 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. Bibcode:2007HydJ...15..945D. doi:10.1007/s10040-007-0191-z.