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Aguas Calientes (volcano)
Aguas Calientes Volcano or Cerro Aguas Calientes, also called Simba, is a cone-shaped stratovolcano located east of the Lascar volcano and north of Laguna Lejía, Chile. It is located within a area where the Cordón de Puntas Negras and the Cordón Chalviri volcanic chains intersect. The volcano is constructed from andesite and dacite containing hornblende and also anhydrite and its pyroclastics are all older than Lascar. It has a diameter of about . Some xenoliths of calc-alkaline material are found in Aguas Calientes lavas, and magma mixing has generated lavas containing andesite inclusions in dacites. One eruption of Aguas Calientes postdates the first centre of Lascar and was originally linked to the Lascar Piedras Grandes eruption, before sampling on the deposits of this eruption indicated a relationship with the Lascar volcano itself. Effusion of lava ceased after the cone was built. One summit lava flow may be of Holocene age, but no evidence of historical activity is fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lascar (volcano)
Lascar is a stratovolcano in Chile within the Central Volcanic Zone of the Andes, a volcanic arc that spans Peru, Bolivia, Argentina and Chile. It is the most active volcano in the region, with records of eruptions going back to 1848. It is composed of two separate cones with several summit craters. The westernmost crater of the eastern cone is presently active. Volcanic activity is characterized by constant release of volcanic gas and occasional vulcanian eruptions. Lascar has been active since at least 56,000 years ago, though some argue for activity beginning 220,000 years ago. The first known activity occurred at the eastern cone and was characterized by lava flows, before shifting to the western cone where lava domes were emplaced. An eruption event known as Piedras Grandes was followed by the large Soncor eruption. A new western edifice was constructed on top of the Soncor vent, during the Holocene activity then shifted again to the eastern edifice and continues there ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacite
Dacite () is a volcanic rock formed by rapid solidification of lava that is high in silica and low in alkali metal oxides. It has a fine-grained (aphanitic) to porphyritic texture and is intermediate in composition between andesite and rhyolite. It is composed predominantly of plagioclase feldspar and quartz. Dacite is relatively common, occurring in many tectonic settings. It is associated with andesite and rhyolite as part of the subalkaline volcanic rock, subalkaline tholeiite, tholeiitic and calc-alkaline magma series. Composition Dacite consists mostly of plagioclase feldspar and quartz with biotite, hornblende, and pyroxene (augite or enstatite). The quartz appears as rounded, corroded phenocrysts, or as an element of the ground-mass. The plagioclase in dacite ranges from oligoclase to andesine and labradorite. Sanidine occurs, although in small proportions, in some dacites, and when abundant gives rise to rocks that form rhyodacite, transitions to the rhyolites. The rel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stratovolcanoes Of Chile
A stratovolcano, also known as a composite volcano, is a conical volcano built up by many layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with a summit crater and periodic intervals of explosive eruptions and effusive eruptions, although some have collapsed summit craters called calderas. The lava flowing from stratovolcanoes typically cools and hardens before spreading far, due to high viscosity. The magma forming this lava is often felsic, having high-to-intermediate levels of silica (as in rhyolite, dacite, or andesite), with lesser amounts of less-viscous mafic magma. Extensive felsic lava flows are uncommon, but have travelled as far as . Stratovolcanoes are sometimes called composite volcanoes because of their composite stratified structure, built up from sequential outpourings of erupted materials. They are among the most common types of volcanoes, in contrast to the less common shield volcanoe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Antofagasta Region
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 pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terrestrial planet with a thin atmosphere (less than 1% that of Earth's), and has a crust primarily composed of elements similar to Earth's crust, as well as a core made of iron and nickel. Mars has surface features such as impact craters, valleys, dunes and polar ice caps. It has two small and irregularly shaped moons, Phobos (moon), Phobos and Deimos (moon), Deimos. Some of the most notable surface features on Mars include Olympus Mons, the largest volcano and List of tallest mountains in the Solar System, highest known mountain in the Solar System and Valles Marineris, one of the largest canyons in the Solar System. The North Polar Basin (Mars), Borealis basin in the Northern Hemisphere covers approximately 40% of the planet and may be a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Crater Lake
A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption. Formation Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption. Lakes in maars fill medium-sized craters where an eruption deposited debris around a vent. Crater lakes form as the created depression, within the crater rim, is filled by water. The water may come from precipitation, groundwater circulation (often hydrothermal fluids in the case of volcanic craters) or melted ice. Its level rises until an equilibrium is reached between the rates of incoming and outgoing water. Sources of water loss singly or together may include evaporation, subsurface seepage, and, in places, surface leakage or overflow when the lake level reaches the lowest point on its rim. At such a saddle location, the upper portion of the lake is contained only by its adjacent natural volcanic dam; continued leakage through or surface outflow ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glaciation
A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The Last Glacial Period ended about 15,000 years ago. The Holocene is the current interglacial. A time with no glaciers on Earth is considered a greenhouse climate state. Quaternary Period Within the Quaternary, which started about 2.6 million years before present, there have been a number of glacials and interglacials. At least eight glacial cycles have occurred in the last 740,000 years alone. Penultimate Glacial Period The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. It began about 194,000 years ago and ended 135,000 years ago, with the beginning of the Eemian interglacial. Last Glacial Period The last glacial period was the most recent glacial period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anhydrite
Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium ( baryte) and strontium ( celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best developed of the three cleavages, the lustre is pearly; on other surfaces it is glassy. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around under normal atmospheric conditions. Anhydrite is comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hornblende
Hornblende is a complex inosilicate series of minerals. It is not a recognized mineral in its own right, but the name is used as a general or field term, to refer to a dark amphibole. Hornblende minerals are common in igneous and metamorphic rocks. The general formula is . Physical properties Hornblende has a hardness of 5–6, a specific gravity of 3.0 to 3.6, and is typically an opaque green, dark green, brown, or black color. It tends to form slender prismatic to bladed crystals, diamond-shaped in cross-section, or is present as irregular grains or fibrous masses. Its planes of cleavage intersect at 56° and 124° angles. Hornblende is most often confused with the pyroxene series and biotite mica, which are also dark minerals found in granite and charnockite. Pyroxenes differ in their cleavage planes, which intersect at 87° and 93°. Hornblende is an inosilicate (chain silicate) mineral, built around double chains of silica tetrahedra. These chains extend the length of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by volume, with at least 65% of the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andes
The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S latitude), and has an average height of about . The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina. Along their length, the Andes are split into several ranges, separated by intermediate depressions. The Andes are the location of several high plateaus—some of which host major cities such as Quito, Bogotá, Cali, Arequipa, Medellín, Bucaramanga, Sucre, Mérida, El Alto and La Paz. The Altiplano plateau is the world's second-highest after the Tibetan plateau. These ranges are in turn grouped into three major divisions based on climate: the Tropical Andes, the Dry Andes, and the Wet Andes. The Andes Mountains are the highest m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laguna Lejía
Laguna (Italian and Spanish for lagoon) may refer to: People * Abe Laguna (born 1992), American DJ known as Ookay * Andrés Laguna (1499–1559), Spanish physician, pharmacologist, and botanist * Ana Laguna (born 1955), Spanish-Swedish ballet dancer, court dancer and professor * Benjamín Máximo Laguna y Villanueva (1822–1902), Spanish forester * Frederica de Laguna (1906–2004), American anthropologist * Fábio Laguna (born 1977), Brazilian keyboardist * Grace de Laguna (1878–1978), American philosopher * Ieva Lagūna (born 1990), Latvian model * Jorge Laguna (born 1993), Mexican footballer * José Dapena Laguna (1912–1991), Puerto Rican politician - mayor of Ponce, Puerto Rico * José Durand Laguna (1889–1958), Argentine football manager * Justo Oscar Laguna (1929–2011), Argentinian bishop * Kenny Laguna (born 1948), American songwriter and record producer * Ricardo Laguna (born 1982), Mexican-American professional BMX rider and television personality * Theodore de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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