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Pan-African Orogeny
The Pan-African orogeny was a series of major Neoproterozoic orogenic events which related to the formation of the supercontinents Gondwana and Pannotia about 600 million years ago. This orogeny is also known as the Pan-Gondwanan or Saldanian Orogeny. The Pan-African orogeny and the Grenville orogeny are the largest known systems of orogenies on Earth. The sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. History and terminology The term ''Pan-African'' was coined by for a tectono-thermal event at about 500 Ma when a series of mobile belts in Africa formed between much older African cratons. At the time, other terms were used for similar orogenic events on other continents, i.e. '' Brasiliano'' in South America; ''Adelaidean'' in Australia; and ''Beardmore'' in Antarctica. Later, when plate tectonics became generally accepted, the term ''Pan-A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neoproterozoic
The Neoproterozoic Era is the unit of geologic time from 1 billion to 538.8 million years ago. It is the last era of the Precambrian Supereon and the Proterozoic Eon; it is subdivided into the Tonian, Cryogenian, and Ediacaran periods. It is preceded by the Mesoproterozoic Era and succeeded by the Paleozoic Era of the Phanerozoic Eon. The most severe glaciation known in the geologic record occurred during the Cryogenian, when ice sheets may have reached the equator and formed a "Snowball Earth". The earliest fossils of complex multicellular life are found in the Ediacaran Period. These organisms make up the Ediacaran biota, including the oldest definitive animals in the fossil record. According to Rino and co-workers, the sum of the continental crust formed in the Pan-African orogeny and the Grenville orogeny makes the Neoproterozoic the period of Earth's history that has produced most continental crust. Geology At the onset of the Neoproterozoic the supercontinent Rod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saldania Belt
''Ormocarpum'' is a genus of legume in the family Fabaceae, and was recently assigned to the informal monophyletic ''Dalbergia'' clade of the Dalbergieae. Species ''Ormocarpum'' comprises the following species: * '' Ormocarpum bernierianum'' (Baill.) Du Puy & Labat * '' Ormocarpum cochinchinense'' (Lour.) Merr. * ''Ormocarpum drakei'' R. Vig. * ''Ormocarpum flavum'' J.B. Gillett * ''Ormocarpum keniense'' J.B. Gillett * ''Ormocarpum kirkii'' S. Moore * ''Ormocarpum klainei'' Tisser. * ''Ormocarpum megalophyllum'' Harms * ''Ormocarpum muricatum'' Chiov. * ''Ormocarpum pubescens'' (Hochst.) Cufod. * ''Ormocarpum schliebenii'' Harms * ''Ormocarpum sennoides'' (Willd.) DC. * ''Ormocarpum suberosum'' Teijsm. & Binn. * ''Ormocarpum trachycarpum'' (Taub.) Harms * ''Ormocarpum trichocarpum'' (Taub.) Engl. * ''Ormocarpum verrucosum ''Ormocarpum'' is a genus of legume in the family Fabaceae, and was recently assigned to the informal monophyletic ''Dalbergia'' cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gariep Belt
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 Afrikaa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lufilian Arc
The Lufilian Arc (or Lufilian Belt) is part of a system of orogenic belts in southern Africa formed during the Pan-African orogeny, a stage in the formation of the Gondwana supercontinent. It extends across eastern Angola, the Katanga Province of the southern Democratic Republic of the Congo and the northwest of Zambia. The arc is about long. It has global economic importance owing to its rich deposits of copper and cobalt. Evolution The Katanga Supergroup of Neoproterozoic sediments rests on a basement formed in the Paleoproterozoic or Mesoproterozoic eras. The lower basement is made of granites, gneisses and schists formed during the Eburnean age, about 2100–2000 Ma. The upper basement extends under part of the arc in Zambia and is mostly made of schists, quartzites and quartz-muscovite schists. The Kibaran orogeny deformed and metamorphosed the upper basement between 1350 Ma and 1100 Ma. The Katanga supergroup sediments are from to thick. Rifting between the Congo and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Snowball Earth
The Snowball Earth hypothesis proposes that, during one or more of Earth's icehouse climates, the planet's surface became entirely or nearly entirely frozen. It is believed that this occurred sometime before 650 M.Y.A. (million years ago) during the Cryogenian period. Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for global glaciation and the geophysical feasibility of an ice- or slush-covered ocean, and they emphasize the difficulty of escaping an all-frozen condition. A number of unanswered questions remain, including whether Earth was a full snowball or a "slushball" with a thin equatorial band of open (or seasonally open) water. The snowball-Earth episodes are proposed to have occurred before the sudden radiation of multicellular bioforms kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damara Ocean
Damara may refer to: * Damara (people), Namibian people * Damara (feudal landlord), landlords of ancient Kashmir * Damara, Central African Republic, a town * Damara sheep, a breed of sheep * Damara (Forgotten Realms), a fictional kingdom in the Forgotten Realms D&D campaign setting * Damara Megido, a character from the webcomic ''Homestuck'' * Damara Capital, a firm of property developers and managers in the BBC Radio 4 soap, ''The Archers ''The Archers'' is a BBC radio drama on BBC Radio 4, the corporation's main spoken-word channel. Broadcast since 1951, it was famously billed as "an everyday story of country folk" and is now promoted as "a contemporary drama in a rural sett ...'' See also * Damaraland, a region in Namibia inhabited by the Damara people {{disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adamastor Ocean
The Adamastor Ocean was a "proto-Atlantic" ocean that formed with the break-up of the Rodinia supercontinent 780-750 . It separated the Río de la Plata Craton from the Congo Craton. The inversion of the Adamastor Ocean began about 640 Ma with the development of a large back-arc basin along the western margin of the Kalahari Craton, and the ocean closed when Río de la Plata collided with Kalahari about 545 Ma along the sinistral Sierra Ballena Shear Zone. The São Francisco Craton and the Río de la Plata Craton amalgamated 630–620 Ma, closing the Adamastor Ocean on the South American side and forming the Mantiqueira Mountains around 600 Ma. In 2020 a group of geologists proposed an alternative model for the Adamastor Ocean in which it is reduced to a intracontinental rift system with only some minor oceanic crust developing in its southern part. Etymology South African geologist Chris Hartnady named the Precambrian ocean after the mythical giant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalahari Craton
The Kalahari Craton is a craton, an old and stable part of the continental lithosphere, that occupies large portions of South Africa, Botswana, Namibia and Zimbabwe. It consists of two cratons separated by the Limpopo Belt: the larger Kaapvaal Craton to the south and the smaller Zimbabwe Craton to the north. The Namaqua Belt is the southern margin of the Kaapvaal Craton. Parts of the Kalahari Craton are now in East Antarctica (the Grunehogna Craton) and West Antarctica ( Haag Nunataks) and the Falkland Islands. The name was first introduced by . Formation Following a terminology introduced in 2008, the Archaean-Palaeoproterozoic core of the craton is called the Proto-Kalahari Craton. This core plus accreted Mesoproterozoic crust and dispersed non-African fragments compose the Kalahari Craton. Before the Pan-African Orogeny, the Kalahari Craton was much larger than it is today, but its sutures and therefore its extent are difficult to locate due to later overprinting. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congo Craton
The Congo Craton, covered by the Palaeozoic-to-recent Congo Basin, is an ancient Precambrian craton that with four others (the Kaapvaal, Zimbabwe, Tanzania, and West African cratons) makes up the modern continent of Africa. These cratons were formed between about 3.6 and 2.0 billion years ago and have been tectonically stable since that time. All of these cratons are bounded by younger fold belts formed between 2.0 billion and 300 million years ago. The Congo Craton occupies a large part of central southern Africa, extending from the Kasai region of the DRC into Sudan and Angola. It forms parts of the countries of Gabon, Cameroon, and the Central African Republic. A small portion extends into Zambia as well, where it is called the Bangweulu Block. Congo–São Francisco The Congo Craton and the São Francisco Craton are stable Archaean blocks that formed a coherent landmass until the opening of the South Atlantic Ocean during the break-up of Gondwana ( 2000–130 Ma). Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Damara Belt
The Damara orogeny was part of the Pan-African orogeny. The Damara orogeny occurred late in the creation of Gondwana, at the intersection of the Congo and the Kalahari cratons.; ; ; ; The Damara orogeny involved the suturing of the Congo– São Francisco and Río de la Plata cratons at 580–550 Ma (together with India forming northern Gondwana) before the amalgamation of the Kalahari and Mawson cratons in the Kuunga–Damara orogeny at 530 Ma (southern Gondwana). The Adamastor Ocean closed southwards from the Araçuaı́ Belt (São Francisco Craton, now in South America) to the Kaoko Belt (Congo Craton, now in Africa) 580–550 Ma and 545–530 Ma Gariep Belt (Kalahari Craton, now in southern Africa). The Damara orogeny saw a peak in deformation and metamorphism at 530–500 Ma. Thrusting occurred onto the Kalahari Craton until 480 Ma. Río de la Plata docked to Congo before the closure of the Damara Belt oceans (Mozambique and Khomas) whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zambezi Belt
The Zambezi Belt is an area of orogenic deformation in southern Zambia and northern Zimbabwe. It is a segment of a broader belt lying between the Congo Craton and the Kalahari Craton, which also includes the Lufilian Arc and the Damaran Belt. The eastern margin of the belt interacts with the north-south Eastern African orogen. The Zambezi belt shows evidence of two large tectonothermal events, one between about 890-880 Ma and the other about 550-520 Ma. Both events reworked existing Archean to Mesoproterozoic components, with small additions of younger material. The second event was caused by the collision of the Congo and Kalahari cratons during the assembly of the Gondwana supercontinent at the end of the Neoproterozoic. The belt includes the Kadunguri Whiteschists, which were formed by metasomatic alteration at high pressures of ocean-island-type metabasalts during the Pan-African orogeny. The Mwembeshi Shear Zone forms the northern boundary of the Zambezi Belt, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
