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Eastern Block Of North China Craton
The Eastern Block of the North China Craton is one of the Earth's oldest pieces of continent. It is separated from the Western Block of North China Craton, Western Block by the Trans-North China Orogen. It is situated in northeastern China and North Korea. The Block contains rock exposures older than 2.5 billion years (pre-Neoarchean and the Neoarchean Era). It serves as an ideal place to study how the crust was formed in the past and the related Tectonics, tectonic settings. Geologists are able to deduce the past environments and tectonic events by studying geological records like rocks and geological structures. The oldest components of the Eastern Block were first formed more than 4 billion years ago (the Hadean Eon). It later experienced numerous geological events between 3.8 and 1.85 billion years ago (the Eoarchean to Paleoproterozoic Era), including recurring volcanic eruptions and metamorphism, metamorphic events. Therefore, most of the rocks were reworked and highly metamo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Location Of The Eastern Block Of North China Craton
In geography, location or place are used to denote a region (point, line, or area) on Earth's surface or elsewhere. The term ''location'' generally implies a higher degree of certainty than ''place'', the latter often indicating an entity with an ambiguous boundary, relying more on human or social attributes of place identity and sense of place than on geometry. Types Locality A suburb, locality, human settlement, settlement, or populated place is likely to have a well-defined name but a boundary that is not well defined varies by context. London, for instance, has a legal boundary, but this is unlikely to completely match with general usage. An area within a town, such as Covent Garden in London, also almost always has some ambiguity as to its extent. In geography, location is considered to be more precise than "place". Relative location A relative location, or situation, is described as a displacement from another site. An example is "3 miles northwest of Seattle". Absolute lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rift
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 poi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Law Of Included Fragments
The law of included fragments is a method of relative dating in geology. Essentially, this law states that clasts in a rock are older than the rock itself. One example of this is a xenolith, which is a fragment of country rock that fell into passing magma as a result of stoping. Another example is a derived fossil, which is a fossil that has been eroded from an older bed and redeposited into a younger one.D. Armstrong, F. Mugglestone, R. Richards and F. Stratton, OCR AS and A2 Geology, Pearson Education Limited, 2008, p. 276 This is a restatement of Charles Lyell's original principle of inclusions and components from his 1830 to 1833 multi-volume ''Principles of Geology'', which states that, with sedimentary rocks, if inclusions (or clasts) are found in a formation, then the inclusions must be older than the formation that contains them. For example, in sedimentary rocks, it is common for gravel from an older formation to be ripped up and included in a newer layer. A similar sit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures and pressures than schist. Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct cleavage. Gneisses are common in the ancient crust of continental shields. Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss. Description Orthogneiss from the Czech Republic In traditional English and North American usage, a gneiss is a coarse-grained metamorphic rock showing compositional banding (gneissic banding) but poorly developed schistosity and indistinct cleavage. In other words, it is a metamorphic rock composed of mineral grains easily seen with the unaided eye, which form obvious compositional layers, but which has only a weak tendency to fracture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trondhjemite
Trondhjemite is a leucocratic (light-colored) intrusive igneous rock. It is a variety of tonalite in which the plagioclase is mostly in the form of oligoclase. Trondhjemites that occur in the oceanic crust or in ophiolites are usually called plagiogranites. Trondhjemite is common in Archean terranes occurring in conjunction with tonalite and granodiorite as the ''TTG'' (tonalite–trondhjemite–granodiorite) orthogneiss suite. Trondhjemite dikes also commonly form part of the sheeted dike complex of an ophiolite. The rock type was first described by V.M. Goldschmidt in 1916. The name of the rock type is derived from the city of Trondheim Trondheim ( , , ; sma, Tråante), historically Kaupangen, Nidaros and Trondhjem (), is a city and municipality in Trøndelag county, Norway. As of 2020, it had a population of 205,332, was the third most populous municipality in Norway, and ..., Norway. Notes References * * Further reading * Best, Myron G. (2002) ''Igneous and Me ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eoarchean Geology
Eoarchean geology is the study of the oldest preserved crustal fragments of Earth during the Eoarchean era from 4 to 3.6 billion years ago. Major well-preserved rock units dated Eoarchean are known from three localities, the Isua Greenstone Belt in Southwest Greenland, the Acasta Gneiss in the Slave Craton in Canada, and the Nuvvuagittuq Greenstone Belt in the eastern coast of Hudson Bay in Quebec. From the dating of rocks in these three regions scientists suggest that plate tectonics could go back as early as Eoarchean. All 3 regions contain an abundance of Archean felsic volcanic rocks, including tonalite, trondhjemite and granodiorite (TTG) series rocks, with minor granulite to amphibolite facies gneiss complexes, which means that the original characters of the rocks has been disturbed by at least one ductile deformation at deep crustal conditions. Eoarchean geology is important in investigating earth's tectonic history. It is because the earth had just undergone an tran ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposure Map Of Archean Basement Rocks And Jiao-Liao-Ji Belt
Exposure or Exposures may refer to: People * The Exposures, a pseudonym for German electronic musician Jan Jeline Arts, entertainment, and media Films * ''Exposure'' (film), a 1932 American film * ''Exposure'', another name for the 1991 movie '' A Grande Arte'' starring Peter Coyote * Exposure (sculpture) a 2010 steel frame sculpture located in the Netherlands Literature * ''Exposure'' (Peet novel), a 2008 sports novel by Mal Peet * ''Exposure'' (Reichs novel), a 2014 novel in the Virals series by Kathy and Brendan Reichs * '' Exposure: Poisoned Water, Corporate Greed, and One Lawyer's Twenty-Year Battle Against DuPont'', a 2019 book by Robert Bilott * ''Exposure'', 2016 novel by Helen Dunmore * "Exposure", written in 1918, published in 1920, poem by Wilfred Owen Music Albums * ''Exposure'' (Exposé album), 1987 * ''Exposure'' (Robert Fripp album), released in 1979 * ''Exposure'' (Gary Numan album), a compilation album, 2002 * ''Exposure'' (Esperanza Spalding album), 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Xinyang
Xinyang (; postal: Sinyang) is a prefecture-level city in southeastern Henan province, People's Republic of China, the southernmost administrative division in the province. Its total population was 6,234,401 according to the 2020 census. As of the 2010 census, 1,230,042 of them lived in the built-up (or metro) area made of two urban districts, Pingqiao and Shihe. Geography Geography of city The prefecture-level city of Xinyang has a total land area of . The city is located in the southernmost part of Henan Province on the south bank of the Huai River and in the middle of the Dabie Mountains area. It borders the cities Zhumadian to the north and Nanyang to the northwest, and the provinces of Anhui and Hubei to the east and south respectively. The region where Xinyang is located is considered a subtropical area and the Dabie mountainous terrain is mainly to the north, south, and east of the city. Climate Xinyang has a monsoon-influenced, four-season humid subtropical climat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hebei
Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, and 0.3% Mongol. Three Mandarin dialects are spoken: Jilu Mandarin, Beijing Mandarin and Jin. Hebei borders the provinces of Shanxi to the west, Henan to the south, Shandong to the southeast, Liaoning to the northeast, and the Inner Mongolia Autonomous Region to the north. Its economy is based on agriculture and manufacturing. The province is China's premier steel producer, although the steel industry creates serious air pollution. Five UNESCO World Heritage Sites can be found in the province, the: Great Wall of China, Chengde Mountain Resort, Grand Canal, Eastern Qing tombs, and Western Qing tombs. It is also home to five National Famous Historical and Cultural Cities: Handan, Baoding, Chengde, Zhengding and Shanhaiguan. Historic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anshan
Anshan () is an inland prefecture-level city in central-southeast Liaoning province, People's Republic of China, about south of the provincial capital Shenyang. As of the 2020 census, it was Liaoning's third most populous city with a population of 3,325,372 people, over an area of about spanning from east to the west. Its built-up area encompassing the 4 Anshan urban districts (1,543,696 inhabitants), the 4 out of 5 urban Liaoyang districts (796,962 inhabitants, Gongchangling not being conurbated yet) and Liaoyang county largely being conurbated, was home to 2,712,789 million inhabitants in 2020. The city's name came from the horse saddle-like shape of a nearby mountain south of the city, which can be seen on the left (west) about five minutes before the northbound train arrives at Anshan railway station. Anshan is home to the Anshan Iron and Steel Group, one of the largest steel producers in China. Anshan is sister city with Sheffield, United Kingdom. Anshan holds one-t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiometric Dating
Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate of decay. The use of radiometric dating was first published in 1907 by Bertram Boltwood and is now the principal source of information about the absolute age of rocks and other geological features, including the age of fossilized life forms or the age of Earth itself, and can also be used to date a wide range of natural and man-made materials. Together with stratigraphic principles, radiometric dating methods are used in geochronology to establish the geologic time scale. Among the best-known techniques are radiocarbon dating, potassium–argon dating and uranium–lead dating. By al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadean Zircon
Hadean zircon is the oldest-surviving crustal material from the Earth's earliest geological time period, the Hadean eon, about 4 billion years ago. Zircon is a mineral that is commonly used for radiometric dating because it is highly resistant to chemical changes and appears in the form of small crystals or grains in most igneous and metamorphic host rocks. Hadean zircon has very low abundance around the globe because of recycling of material by plate tectonics. When the rock at the surface is buried deep in the Earth it is heated and can recrystallise or melt. In the Jack Hills, Australia, scientists obtained a relatively comprehensive record of Hadean zircon crystals in contrast to other locations. The Jack Hills zircons are found in metamorphosed sediments that were initially deposited around 3 billion years ago, or during the Archean Eon. However, the zircon crystals there are older than the rocks that contain them. Many investigations have been carried out to find the absolute ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
