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Choquelimpie
Choquelimpie is a high volcano in Chile. It is constructed from several separate layers of andesite and dacite on top of Tertiary and Precambrian layers. The volcano was active over six million years ago, with the neighbouring volcano Ajoya active over seven million years ago. Since then, erosion and glacial activity have dramatically reduced the height of the volcano and excavated a central depression. Choquelimpie is part of one of two belts of volcanically-generated ore deposits. It is mined for silver and gold since Spanish times and a prospect in the 1980s indicated the presence of over eleven tons of ore. Geography Choquelimpie is located in Parinacota province, Arica y Parinacota Region, Chile. The border with Bolivia is east. The basement rock surrounding Choquelimpie is mostly of Tertiary age or younger, with the exception of a narrow segment of Precambrian schists. Some of the Tertiary rocks are sediments which accumulated in basins and are of volcanic or biogenic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parinacota Volcano
Parinacota (in Hispanicized spelling), Parina Quta or Parinaquta is a dormant stratovolcano on the border of Chile and Bolivia. Together with Pomerape it forms the Nevados de Payachata volcanic chain. Part of the Central Volcanic Zone of the Andes, its summit reaches an elevation of above sea level. The symmetrical cone is capped by a summit crater with widths of or . Farther down on the southern slopes lie three parasitic centres known as the Ajata cones. These cones have generated lava flows. The volcano overlies a platform formed by lava domes and andesitic lava flows. The volcano started growing during the Pleistocene and formed a large cone. At some point between the Pleistocene and the Holocene, the western flank of the volcano collapsed, generating a giant landslide that spread west and formed a large, hummocky landslide deposit. The avalanche crossed and dammed a previously existing drainage, impounding or enlarging Lake Chungará; numerous other lakes now forming th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caldera Lauca
The Caldera Lauca is a caldera in the Arica y Parinacota Region of Chile. It is located in the Cordillera Occidental, in the valley of the Lauca River. The elliptic caldera has an east-west extension of and in north-south direction, buried beneath the late Miocene Vilañuñumani-Tejene volcanic complex in the north and ending at Chucal in the south. The 21 mya Oxaya Ignimbrite originates in the caldera. The eastern border of the caldera is buried beneath younger ignimbrites and deposits but is located east of the Guallatiri volcano. An Oligocene fault marks the western edge of the caldera. The caldera is filled up to thick with of ignimbrite. Rocks have varying SiO2 content from 58 to 73%. One sample of Lauca ignimbrite is younger than the Lauca caldera. It forms one of the older volcanic centres in the Payachata region, together with the Ajoya- Choquelimpie volcanic complex and the Caquena domes, while Pomerape and Parinacota are more recent volcanic centres. See also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Calc-alkaline
The calc-alkaline magma series is one of two main subdivisions of the subalkaline magma series, the other subalkaline magma series being the tholeiitic series. A magma series is a series of compositions that describes the evolution of a mafic magma, which is high in magnesium and iron and produces basalt or gabbro, as it fractionally crystallizes to become a felsic magma, which is low in magnesium and iron and produces rhyolite or granite. Calc-alkaline rocks are rich in alkaline earths ( magnesia and calcium oxide) and alkali metals and make up a major part of the crust of the continents. The diverse rock types in the calc-alkaline series include volcanic types such as basalt, andesite, dacite, rhyolite, and also their coarser-grained intrusive equivalents (gabbro, diorite, granodiorite, and granite). They do not include silica-undersaturated, alkalic, or peralkaline rocks. Geochemical characterization Rocks from the calc-alkaline magma series are distinguished from rocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orpiment
Orpiment is a deep-colored, orange-yellow arsenic sulfide mineral with formula . It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and is formed both by sublimation and as a byproduct of the decay of another arsenic sulfide mineral, realgar. Orpiment takes its name from the Latin ''auripigmentum'' (''aurum'', "gold" + ''pigmentum'', "pigment") because of its deep-yellow color. Historical uses Orpiment was traded in the Roman Empire and was used as a medicine in China, even though it is very toxic. It has been used as fly poison and to tip arrows with poison. Because of its striking color, it was of interest to alchemists, both in China and the West, searching for a way to make gold. It also has been found in the wall decorations of Tutankhamun's tomb and ancient Egyptian scrolls, and on the walls of the Taj Mahal. For centuries, orpiment was ground down and used as a pigment in painting and for sealing wax, and was even used in ancient Chi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acanthite
Acanthite is a form of silver sulfide with the chemical formula Ag2S. It crystallizes in the monoclinic system and is the stable form of silver sulfide below . Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C acanthite forms directly. Acanthite is the only stable form in normal air temperature. Occurrence Acanthite is a common silver mineral in moderately low-temperature hydrothermal veins and in zones of supergene enrichment. It occurs in association with native silver, pyrargyrite, proustite, polybasite, stephanite, aguilarite, galena, chalcopyrite, sphalerite, calcite and quartz. Acanthite was first described in 1855 for an occurrence in the Jáchymov (St Joachimsthal) District, Krušné Hory Mts ( Erzgebirge), Karlovy Vary Region, Bohemia, Czech Republic. The name is from the Greek "akantha" meaning thorn or arrow, in reference to its crystal sh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arica
Arica ( ; ) is a Communes of Chile, commune and a port city with a population of 222,619 in the Arica Province of northern Chile's Arica y Parinacota Region. It is Chile's northernmost city, being located only south of the border with Peru. The city is the capital (political), capital of both the Arica Province and the Arica and Parinacota Region. Arica is located at the orocline, bend of South America's western coast known as the Arica Bend or Arica Elbow. At the location of the city are two valleys that dissect the Atacama Desert converge: Azapa Valley, Azapa and Lluta River, Lluta. These valleys provide citrus and olives for export. Arica is an important port for a large inland region of South America. The city serves a free port for Bolivia and manages a substantial part of that country's trade.In addition it is the end station of the Bolivian oil pipeline beginning in Oruro, Bolivia, Oruro. The city's strategic position is enhanced by being next to the Chile Route 5, Pan-Ame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propylite
Metasomatism (from the Greek μετά ''metá'' "change" and σῶμα ''sôma'' "body") is the chemical alteration of a rock by hydrothermal and other fluids. It is the replacement of one rock by another of different mineralogical and chemical composition. The minerals which compose the rocks are dissolved and new mineral formations are deposited in their place. Dissolution and deposition occur simultaneously and the rock remains solid. Synonyms to the word metasomatism are metasomatose and metasomatic process. The word metasomatose can also be used as a name for specific varieties of metasomatism (for example '' Mg-metasomatose'' and '' Na-metasomatose''). Metasomatism can occur via the action of hydrothermal fluids from an igneous or metamorphic source. In the igneous environment, metasomatism creates skarns, greisen, and may affect hornfels in the contact metamorphic aureole adjacent to an intrusive rock mass. In the metamorphic environment, metasomatism is created by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guallatiri
Guallatiri is a high volcano in Chile. It is located southwest of the Nevados de Quimsachata volcanic group and is sometimes considered to be part of that group. It is a stratovolcano with numerous fumaroles around the summit. The summit may be composed of either a lava dome or a pyroclastic cone, while the lower flanks of the volcano are covered by lava flows and lava domes. The volcano's eruptions have produced mostly dacite along with andesite and rhyolite. Guallatiri has been active in historical times with a number of eruptions, the latest in 1960 but a large prehistorical eruption took place 2,600 years ago. Fumarolic and seismic activity is ongoing and has resulted in the deposition of sulfur and other minerals on the volcano. The volcano is covered by an ice cap above elevation that has shrunk and fragmented during the course of the 20th-21st century. Guallatiri, along with several other volcanoes, is part of Lauca National Park and is monitored by SERNAGEOMIN. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taapaca
Taapaca is a Holocene volcanic complex in northern Chile's Arica y Parinacota Region. Located in the Chilean Andes, it is part of the Central Volcanic Zone of the Andean Volcanic Belt, one of four distinct volcanic chains in South America. The town of Putre lies at the southwestern foot of the volcano. Like other volcanoes of the Central Volcanic Zone, Taapaca formed from the subduction of the Nazca Plate beneath the South America Plate. It lies on the western margin of the Altiplano high plateau, on top of older volcanic and sedimentary units. Taapaca has mainly erupted dacite, in the form of numerous lava domes, although an andesitic stratovolcano is also present. Volcanic activity at Taapaca occurred in several stages starting during the Plio-Pleistocene. The emplacement of lava domes was often followed by their collapse and the formation of block-and-ash avalanches, and parts of the volcano underwent sector collapses (large landslides). It was at first assumed that activity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Last Glacial Maximum
The Last Glacial Maximum (LGM), also referred to as the Late Glacial Maximum, was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent. Ice sheets covered much of Northern North America, Northern Europe, and Asia and profoundly affected Earth's climate by causing drought, desertification, and a large drop in sea levels. Based on changes in position of ice sheet margins dated via terrestrial cosmogenic nuclides and radiocarbon dating, growth of ice sheets commenced 33,000 years ago and maximum coverage was between 26,500 years and 19–20,000 years ago, when deglaciation commenced in the Northern Hemisphere, causing an abrupt rise in sea level. Decline of the West Antarctica ice sheet occurred between 14,000 and 15,000 years ago, consistent with evidence for another abrupt rise in the sea level about 14,500 years ago. Glacier fluctuations around the Strait of Magellan suggest the peak in glacial surface area was constrained to betwee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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