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Balfour Formation
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-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. Geology The Balfour Formation overlies the Middleton Formation of the Adelaide Subgroup and underlies the Katberg Formation of the lower Tarkastad Subgroup, all comprising the greater Beaufort Group. The Balfour Formation is composed of five members which are listed below (from oldest to youngest): ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics (lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beaufort West
Beaufort West (Afrikaans: ''Beaufort-Wes''; Xhosa: ''eBhofolo'') is a town in the Western Cape province in South Africa. It is the largest town in the arid Great Karoo region, and is known as the "Capital of the Karoo". It forms part of the Beaufort West Local Municipality, with 34,085 inhabitants in 2011. It is the centre of an agricultural district based mainly on sheep farming, and is a significant town and logistical support hub on the N1 national road. Next door to Beaufort West is the Karoo National Park. Important Permian era fossils have been found in the area to the west of the town. Initially found by David Baird, son of the local magistrate in 1827. The old Town Hall and the Dutch Reformed Church have been declared national monuments. History Beaufort West was the first town to be established in the central Karoo. The town was founded in 1818 and initially named ''Beaufort'' after Henry Somerset, 5th Duke of Beaufort, who was the father of Lord Charles Henry Som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lens (geology)
In geology, a lens or lentil is a body of ore or rock that is thick in the middle and thin at the edges, resembling a convex lens in cross-section. To thin out in all directions is to "lens out", also known as "lensing". The adjectives "lenticular" and "lentiform" are used to describe lens-like formations. Lenticle is a synonym for lentil, but may also refer to a fragment of rock that is lens-shaped. "Lenticule" is used for small lentil. A lentil may also refer a minor unit in a formation of rock, similar to a member but not generally spread out over a large geographical area. In this usage, the lentil thins out towards its edges. Lenticular bedding is a special form of rock interbedded mudrock and cross-laminated rippled 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 silica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mudstone
Mudstone, a type of mudrock, is a fine-grained sedimentary rock whose original constituents were clays or muds. Mudstone is distinguished from ''shale'' by its lack of fissility (parallel layering).Blatt, H., and R.J. Tracy, 1996, ''Petrology.'' New York, New York, W. H. Freeman, 2nd ed, 529 pp. The term ''mudstone'' is also used to describe carbonate rocks ( limestone or dolomite) that are composed predominantly of carbonate mud. However, in most contexts, the term refers to siliciclastic mudstone, composed mostly of silicate minerals. The NASA Curiosity rover has found deposits of mudstone on Mars that contain organic substances such as propane, benzene and toluene. Definition There is not a single definition of mudstone that has gained general acceptance,Boggs 2006, p.143 though there is wide agreement that mudstones are fine-grained sedimentary rocks, composed mostly of silicate grains with a grain size less than . Individual grains this size are too small to be distin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies ( marine snow). Sedimentation may also occur as dissolved minerals precipita ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is distinct from weathering which involves no movement. Removal of rock or soil as clastic sediment is referred to as ''physical'' or ''mechanical'' erosion; this contrasts with ''chemical'' erosion, where soil or rock material is removed from an area by dissolution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres. Agents of erosion include rainfall; bedrock wear in rivers; coastal erosion by the sea and waves; glacial plucking, abrasion, and scour; areal flooding; wind abrasion; groundwater processes; and mass movement processes in steep landscapes like landslides and debris flows. The rates at which such processes act control how fast a surface is eroded. Typically, physical ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orange River
The Orange River (from Afrikaans/ Dutch: ''Oranjerivier'') is a river in Southern Africa. It is the longest river in South Africa. With a total length of , the Orange River Basin extends from Lesotho into South Africa and Namibia to the north. It rises in the Drakensberg mountains in Lesotho, flowing westwards through South Africa to the Atlantic Ocean. The river forms part of the international borders between South Africa and Lesotho and between South Africa and Namibia, as well as several provincial borders within South Africa. Except for Upington, it does not pass through any major cities. The Orange River plays an important role in the South African economy by providing water for irrigation and hydroelectric power. The river was named the Orange River in honour of the Dutch ruling family, the House of Orange, by the Dutch explorer Robert Jacob Gordon. Other names include simply the word for river, in Khoekhoegowab orthography written as !Garib, which is rendered in Af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cistecephalus Assemblage Zone
The ''Cistecephalus'' 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 Teekloof Formation north-west of Beaufort West in the Western Cape, in the upper Middleton Formation, Middleton and lower Balfour Formations respectively from Colesberg of the Northern Cape to east of Graaff-Reinet in the Eastern Cape. The ''Cistecephalus'' Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Late Permian in age. The name of the biozone refers to ''Cistecephalus'', a small, burrowing dicynodont therapsid. It is characterized by the presence of this species, known especially from the upper sections of this biozone, and the first appearance of the dicynodont ''Aulacephalodon''. History The first fossils to be found in the Beaufort Group rocks th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lystrosaurus 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 ( Middelburg, Queenstown, Aliwal North, Nieu-Bethesda) and in the southern and northeastern Free State ( Bethulie, Gariep Dam, Mthatha, Harrismith). The '' Lystrosaurus'' Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Early Triassic in age. The name of the biozone refers to '' Lystrosaurus'', a small to medium-sized dicynodont therapsid. It is characterized by the appearance of further '' Lystrosaurus'' subspecies which are confined to this biozone. '' Lystrosaurus maccaigi'' and '' Lystrosaurus curvatus'' are the only two species found outside the ''Lystrosaurus'' Assemblage Zone in Upper Permian deposit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Daptocephalus 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.Rubidge, B. S. (1995). Biostratigraphy of the Beaufort Group (Karoo Supergroup). ''Biostratigraphic series''. 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. Previously known as the ''Dicyno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nieu-Bethesda
Nieu-Bethesda ( Afrikaans for ''New Bethesda'') is a village in the Eastern Cape at the foot of the Sneeuberge, approximately north of Graaff Reinet. It was founded in 1875 as a church town, like many other Karoo villages, and attained municipal status in 1886. The name is of biblical origin () and means "place of flowing water". History Nieu Bethesda is situated on the farm, Uitkyk, which belonged to BJ Pienaar. There was a very strong water supply on the farm and BJ Pienaar changed the course of the Gats River to drain the marshes and turn the area into fertile fields – where Nieu Bethesda stands today. On 15 December 1874, the farmers of this area met for the first time with a view to establishing a village and Dutch Reformed Church congregation. A town council was elected. In February 1875, a petition group of 169 men met the church council of Graaff-Reinet, headed by the Reverend Charles Murray, son of the first preacher Andrew Murray. On the same day, negotiations were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graaff-Reinet
Graaff-Reinet is a town in the Eastern Cape Province of South Africa. It is the oldest town in the province. It is also the sixth-oldest town in South Africa, after Cape Town, Stellenbosch, Simon's Town, Paarl and Swellendam. The town was the centre of a short-lived republic in the late 18th century. The town was a starting point for Great Trek groups led by Gerrit Maritz and Piet Retief and furnished large numbers of the Voortrekkers in 1835–1842. Graaff-Reinet is home to more national monuments than any other town or city in South Africa. It is also known for being a flourishing market for agricultural produce, noted for its mohair industry, and sheep and ostrich farming. History Graaff-Reinet was established by the Dutch East India Company in 1786, after Cape Town in 1652, Stellenbosch in 1679, Paarl in 1687 and Swellendam in 1745. The town is named after then-governor of the Cape Colony, Cornelis Jacob van de Graaff, and his wife. The town was originally establish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
