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Grabens
In geology, a graben () is a depressed block of the crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German, meaning 'ditch' or 'trench'. The word was first used in the geologic context by Eduard Suess in 1883. The plural form is either ''graben'' or ''grabens''. Formation A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with horsts. Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst. Single or multiple graben can produce a rift valley. Half-g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baikal Rift Zone
The Baikal Rift Zone is a series of continental rifts centered beneath Lake Baikal in southeastern Russia. Current strain in the rifts tends to be extending with some shear movement. A series of basins form along the zone for more than , creating a rift valley. The rifts form between the Eurasian Plate to the west and the Amur Plate to the east. Structures To the northwest of the rifts is the Siberian Craton, on the Eurasian Plate. The Sayan-Baikal and Mongolia-Okhotsk mobile belts are formations to the southeast of the rifts; beyond the Sayan-Baikal fold belt is the Amur Plate. Basins form along the rift. There are three basins in the area, the South Basin, Central Basin, and North Basin. In the North, half-grabens form smaller basins, such as the North Baikal Basin, and the Chara-Tokka Basin. The Central Basin is the deepest in the rift system. The largest fault it contains is the Morskiy Fault; however, another fault, the Primorsky is becoming the primary fault in the rift. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graben Afar ASTER 20020327
In geology, a graben () is a depression (geology), depressed block of the Crust (geology), crust of a planet or moon, bordered by parallel normal faults. Etymology ''Graben'' is a loan word from German language, German, meaning 'ditch' or 'trench'. The word was first used in the geologic context by Eduard Suess in 1883. The plural form is either ''graben'' or ''grabens''. Formation A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side by side with Horst (geology), horsts. Horst and graben structures indicate tensional forces and crustal stretching. Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Horst (geology)
In physical geography and geology, a horst is a raised fault block bounded by Fault (geology), normal faults. Horsts are typically found together with Graben, grabens. While a horst lifted or remains stationary, the grabens on either side Subsidence, subside. This is often caused by Extensional tectonics, extensional forces pulling apart the crust. Horsts may represent features such as plateaus, mountains, or ridges on either side of a valley. Horsts can range in size from small fault-blocks, up to large regions of stable continent that have not been not folded or warped by tectonic forces. The word ''Horst'' in German language, German means "mass" or "heap," and was first used in the geological sense in 1883 by Eduard Suess in ''The Face of the Earth.''Originally published in 1883 in German as "Das Antlitz der Erde", translated and published in English in 1904 Geomorphology Horsts may have either symmetrical or asymmetrical cross-sections. If the normal faults to either side ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East African Rift
The East African Rift (EAR) or East African Rift System (EARS) is an active continental rift zone in East Africa. The EAR began developing around the onset of the Miocene, 22–25 million years ago. In the past it was considered to be part of a larger Great Rift Valley that extended north to Asia Minor. A narrow zone, the rift is a developing divergent tectonic plate boundary where the African Plate is in the process of splitting into two tectonic plates, called the Somali Plate and the Nubian Plate, at a rate of 6-7 mm per year. The rift system consists of three microplates, the Victoria Microplate to the north, and the Rovuma and Lwandle microplates to the south. The Victoria Microplate is rotating anti-clockwise with respect to the African plate. Its rotation is caused by the configuration of mechanically weaker and stronger lithospheric regions in the EARS. Extent A series of distinct rift basins, the East African Rift System extends over thousands of kilometers. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lambert Graben
Lambert Graben is a graben in Antarctica. It intersects the coast at Prydz Bay and contains the largest glacier in the world, Lambert Glacier. The graben is a Permian rift which contains coal beds. The graben has been correlated with the coal bearing Godavari Valley of the Indian Peninsula prior to the breakup of Gondwana. Geology The graben is a Late Palaeozoic-Mesozoic triple junction failed rift. Precambrian metamorphic rocks, composed of granulite-facies sequences intruded by granites and pegmatites, are overlain by the Permian sedimentary Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ... Amery Group. These rocks outcrop on the Platforma Kamenistaja and Else Platform within the northern Jetty Peninsula (Jetty Oasis). References Structural geology Landforms of Mac. Rob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift Valley
A rift valley is a linear shaped lowland between several highlands or mountain ranges created by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear depression may subsequently be further deepened by the forces of erosion. More generally the valley is likely to be filled with sedimentary deposits derived from the rift flanks and the surrounding areas. In many cases rift lakes are formed. One of the best known examples of this process is the East African Rift. On Earth, rifts can occur at all elevations, from the sea floor to plateaus and mountain ranges in continental crust or in oceanic crust. They are often associated with a number of adjoining subsidiary or co-extensive valleys, which are typically considered part of the principal rift valley geologically. Earth's rift valleys The most extensive rift valley is located along the crest of the mid-ocean ridge system and is the result of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift (geology)
In geology, a rift is a linear zone where the lithosphere is being pulled apart and is an example of extensional tectonics. Typical rift features are a central linear downfaulted depression, called a graben, or more commonly a half-graben with normal faulting and rift-flank uplifts mainly on one side. Where rifts remain above sea level they form a rift valley, which may be filled by water forming a rift lake. The axis of the rift area may contain volcanic rocks, and active volcanism is a part of many, but not all, active rift systems. Major rifts occur along the central axis of most mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates. ''Failed rifts'' are the result of continental rifting that failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot. Two of these evolve to the point ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central India
Central India is a loosely defined geographical region of India. There is no clear official definition and various ones may be used. One common definition consists of the states of Chhattisgarh and Madhya Pradesh, which are included in almost all definitions. Like some other definitions this takes the part of northern India that is "central" on an east-west axis. Thus the Central Zonal Council set up by the Indian government includes both these states, plus Uttar Pradesh and Uttarakhand to the north, the last taking the region to the border with Tibet/China in the Himalayas. Another approach, historically more usual, is to base "Central India" on a north-south axis, making it the part of India that is south of North India and north of South India; the definition of North India also varies hugely, but that of South India is generally agreed. This definition includes either some or all of the Deccan, in particular Maharashtra, and may or may not include some of the Indo-G ... [...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 vegetation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angola
, national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordinates = , largest_city = capital , official_languages = Portuguese , languages2_type = National languages , languages2 = , ethnic_groups = , ethnic_groups_ref = , ethnic_groups_year = 2000 , demonym = , government_type = Unitary dominant-party presidential republic , leader_title1 = President , leader_name1 = João Lourenço , leader_title2 = Vice President , leader_name2 = Esperança da CostaInvestidura do Pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lunda Norte Province
Lunda Norte ( en, North Lunda) is a province of Angola. It has an area of 103,760 km² and a population of 862,566. Angola's first President, Agostino Neto, made Lucapa the provincial capital after independence, but the capital was later moved to Dundo. The province borders the Democratic Republic of Congo in the northeast and Lunda Sul in the south. The province is rich in gold and diamonds, but remains vastly underdeveloped and impoverished. UNITA used the money generated from the sale of diamonds to fund war efforts. Cuango River valley, the richest diamond area of Angola is located in the province. Mining is done by notable companies like DeBeers and Endiama. The Lunda province whose capital was Saurimo was created by the Portuguese colonial empire on July 13, 1895. It was divided into Lunda-Sul and Lunda-Norte subdivisions through a constitution act in 1978 by the People's Movement for the Liberation of Angola (MPLA) government. Iron and manganese mining are also importa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
