The Escarpment Grit is a

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period ...

geologic

formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

. It is also referred to as the Nyoka Grit.

Geology

The formation is composed of

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

sediments, mainly

gritstone Gritstone or grit is a hard, coarse-grained, siliceous sandstone. This term is especially applied to such sandstones that are quarried for building material. British gritstone was used for millstones to mill flour, to grind wood into pulp for pa ...

s and coarse

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates) ...

Uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...

is present in the Escarpment Grit of southern

Zambia Zambia (), officially the Republic of Zambia, is a landlocked country at the crossroads of Central Africa, Central, Southern Africa, Southern and East Africa, although it is typically referred to as being in Southern Africa at its most cent ...

Stratigraphy

The Escarpment Grit Formation is the basal unit of the

Upper Karoo Group The Upper Karoo Group is a sequence of Triassic to Early Jurassic sedimentary and volcanic rocks found in Botswana, Zambia, and Zimbabwe. It comprises the Escarpment Grit (in the Mid-Zambezi and Limpopo basins) and the Angwa Sandstone (in the M ...

and underlies the

Pebbly Arkose Formation The Pebbly Arkose Formation is a Late Triassic geologic formation found in southern Africa. Geology Description The formation comprises mainly coarse, arkosic sandstones. Extent The Pebbly Arkose Formation is found in Botswana, Zambia and ...

. It has been dated as Upper Scythian (Early Triassic). The Pebbly Arkose has been correlated to the

Angwa Sandstone Formation The Angwa Sandstone is a geological formation of the mid-Triassic Cabora Bassa Basin and Mana Pools Basin of southern Africa, consisting mainly of sandstone. Description Stratigraphy The Angwa Sandstone is the lowest formation in the Upper Karoo ...

in the Mana Pools and Cabora Bassa Basins, and the

Elliot Formation The Elliot Formation is a geological formation and forms part of the Stormberg Group, the uppermost geological Stratigraphic unit, group that comprises the greater Karoo Supergroup. Outcrops of the Elliot Formation have been found in the northern ...

of the Great

Karoo Basin The Karoo Supergroup is the most widespread stratigraphy, stratigraphic unit in Africa south of the Kalahari Desert. The group (stratigraphy), supergroup consists of a sequence of units, mostly of nonmarine origin, deposited between the Pennsylvan ...

, South Africa.

Flora

Alisporites spores have been identified from the Escarpment Grit in north-western

Zimbabwe Zimbabwe (), officially the Republic of Zimbabwe, is a landlocked country located in Southeast Africa, between the Zambezi and Limpopo Rivers, bordered by South Africa to the south, Botswana to the south-west, Zambia to the north, and Mozam ...

Hydrogeology

This formation constitutes a productive

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

in north-western Zimbabwe, although of limited thickness.

References

{{Reflist Geologic formations of Zambia Geologic formations of Zimbabwe Triassic System of Africa Lower Triassic Series Sandstone formations Fluvial deposits