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Choiyoi Group
Choiyoi Group ( es, Grupo Choiyoi) is a Permian and Triassic-aged group of volcano-sedimentary formations in Argentina and Chile. The group bears evidence of bimodal-style volcanism related to an ancient subduction zone that existed along the western margin of the supercontinent Gondwana. The Choiyoi Group has a large areal extent through western Argentina and parts of Chile, covering at least , but probably around . While the subsurface extent of the group is large, exposures in Argentina are most common in the Frontal Cordillera, the San Rafael Massif and the Principal Cordillera of southern Mendoza and northern Neuquén. In parts the group reaches thicknesses of 2 to 4 km. The plutonic equivalent of the Choiyoi Group volcanic material are mostly granitoids. The remnants of the magmatic arc that produced much of volcanic material is now preserved as a series of batholiths, including the Coastal Batholith of central Chile in the Chilean Coast Range. During the Permian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Group (stratigraphy)
In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups. Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying the stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group, which includes (in ascending order) the Wingate Sandstone, the Moenave Formation, the Kayenta Formation, and the Navajo Sandstone. Each of the formations can be distinguished from its neighbor by its lithology, but all were deposited in the same vast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vega De Los Machos Formation
Vega is the brightest star in the northern constellation of Lyra. It has the Bayer designation α Lyrae, which is Latinised to Alpha Lyrae and abbreviated Alpha Lyr or α Lyr. This star is relatively close at only from the Sun, and one of the most luminous stars in the Sun's neighborhood. It is the fifth-brightest star in the night sky, and the second-brightest star in the northern celestial hemisphere, after Arcturus. Vega has been extensively studied by astronomers, leading it to be termed "arguably the next most important star in the sky after the Sun". Vega was the northern pole star around 12,000 BCE and will be so again around the year 13,727, when its declination will be . Vega was the first star other than the Sun to have its image and spectrum photographed. It was one of the first stars whose distance was estimated through parallax measurements. Vega has functioned as the baseline for calibrating the photometric brightness scale and was one of the stars ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanism
Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a vent. It includes all phenomena resulting from and causing magma within the crust or mantle of the body, to rise through the crust and form volcanic rocks on the surface. Magmas, that reach the surface and solidify, form extrusive landforms. Volcanic processes Magma from the mantle or lower crust rises through the crust towards the surface. If magma reaches the surface, its behavior depends on the viscosity of the molten constituent rock. Viscous (thick) magma produces volcanoes characterised by explosive eruptions, while non-viscous (runny) magma produce volcanoes characterised by effusive eruptions pouring large amounts of lava onto the surface. In some cases, rising magma can cool and solidify without reaching the surface. Inste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bimodal Volcanism
Bimodal volcanism is the eruption of both mafic and felsic lavas from a single volcanic centre with little or no lavas of intermediate composition. This type of volcanism is normally associated with areas of extensional tectonics, particularly rifts. Occurrence Most occurrences of bimodal volcanism are associated with thinning of the crust and the presence of such rocks in metamorphic sequences has been used to provide evidence for past rifting events. Most examples come from areas of active continental rifting such as the Basin and Range Province. Bimodal volcanism has also been described from areas of transtension, the early phases of back-arc basin formation and in the products of both continental and oceanic hotspots (e.g. Yellowstone, Anahim and the Canary Islands). Mechanism of formation Bimodal volcanism is normally explained as a result of partial melting of the crust, creating granitic magma Magma () is the molten or semi-molten natural material from which all i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chile
Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the east and the Pacific Ocean to the west. Chile covers an area of , with a population of 17.5 million as of 2017. It shares land borders with Peru to the north, Bolivia to the north-east, Argentina to the east, and the Drake Passage in the far south. Chile also controls the Pacific islands of Juan Fernández, Isla Salas y Gómez, Desventuradas, and Easter Island in Oceania. It also claims about of Antarctica under the Chilean Antarctic Territory. The country's capital and largest city is Santiago, and its national language is Spanish. Spain conquered and colonized the region in the mid-16th century, replacing Inca rule, but failing to conquer the independent Mapuche who inhabited what is now south-central Chile. In 1818, after declaring in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Argentina
Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, the fourth-largest country in the Americas, and the eighth-largest country in the world. It shares the bulk of the Southern Cone with Chile to the west, and is also bordered by Bolivia and Paraguay to the north, Brazil to the northeast, Uruguay and the South Atlantic Ocean to the east, and the Drake Passage to the south. Argentina is a federal state subdivided into twenty-three provinces, and one autonomous city, which is the federal capital and largest city of the nation, Buenos Aires. The provinces and the capital have their own constitutions, but exist under a federal system. Argentina claims sovereignty over the Falkland Islands, South Georgia and the South Sandwich Islands, and a part of Antarctica. The earliest recorded human prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano-sedimentary Sequence
A volcano-sedimentary sequence is a stratigraphic sequence derived from the alternation and combination of volcanic and sedimentary events. The volcanic material of these sequences may include lava flows and tephra or reworked volcanic material, for example basaltic sand or pebbles. Areas surrounding volcanic arc A volcanic arc (also known as a magmatic arc) is a belt of volcanoes formed above a subducting oceanic tectonic plate, with the belt arranged in an arc shape as seen from above. Volcanic arcs typically parallel an oceanic trench, with the arc lo ...s are common settings for volcano-sedimentary sequences. Edvard G Svendsen is a famous Norwegian geologist who first discovered these sequences in the deepest depths of Portswood. Volcanic rocks Stratigraphy Sedimentary rocks {{Petrology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Río Negro Province
Río Negro (, ''Black River'') is a province of Argentina, located in northern Patagonia. Neighboring provinces are from the south clockwise Chubut, Neuquén, Mendoza, La Pampa and Buenos Aires. To the east lies the Atlantic Ocean. Its capital is Viedma near the Atlantic outlet of the province's namesake river in the eastern extreme. The largest city is in the Andean foothills Bariloche in the far west. Other important cities include General Roca and Cipolletti. History Ferdinand Magellan was the first European explorer to visit the coasts of the provinces in 1520. Italian priest Nicolás Mascardi founded the Jesuit mission ''Nuestra Señora de Nahuel Huapi'' in 1670 at the shore of the Nahuel Huapi Lake, at the feet of the Andes range. Originally part of the Argentine territory called Patagonia (in 1878 the ''Gobernación de la Patagonia''), in 1884 it was organised into the ''Territorio Nacional del Río Negro'' and General Lorenzo Vintter was appointed as the territor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somún Cura Massif
The North Patagonian Massif or Somún Cura Massif (Spanish language, Spanish: ''Macizo Norpatagónico'', ''Macizo Nordpatagónico'' or ''Macizo de Somún Cura'') is a massif in northern Patagonia located in the Argentine provinces of Río Negro Province, Río Negro and Chubut Province, Chubut. The massif is a plateau surrounded by sedimentary basins. The North Patagonian Massif covers an area of approximately . The massif rises above the surrounding topography reaching a maximum of above sea level. Compared to neighboring areas, the North Patagonian Massif has thicker continental crust. Stratigraphy The massif consists of a basement (geology), basement formed by Cambrian, Cambro-Ordovician rocks, overlain by the Silurian, Middle Silurian Sierra Grande Formation. The early Paleozoic section is covered by metamorphic and igneous complexes; the Permian Pailemán Plutonic Complex, Pailemán and Navarrete Plutonic Complexes,González et al., 2014, p.175 and the unconformably overlyin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pablo Groeber
Pablo Groeber (born Paul Friedrich Karl Gröber; 1885–1964) was a German geologist known for his contributions to the understanding of the geology of Tien Shan in Central Asia and the Andes of Nequén and Mendoza Province in Argentina. See also *Juan Brüggen *Henning Illies *Walther Penck *Gustav Steinmann References External linksPaul Gröber (1885-1964) Archiv für Geographie, Leibniz-Institut für Länderkunde (IfL), Leipzig Leipzig ( , ; Upper Saxon: ) is the most populous city in the German state of Saxony. Leipzig's population of 605,407 inhabitants (1.1 million in the larger urban zone) as of 2021 places the city as Germany's eighth most populous, as wel .... 20th-century German geologists Tectonicists Ludwig Maximilian University of Munich alumni University of Buenos Aires faculty National University of La Plata faculty Servicio Geológico Minero personnel German emigrants to Argentina 1885 births 1964 deaths University of Strasbourg alumni ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra De Calencó
Sierra (Spanish for "mountain range" and "saw", from Latin ''serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieves, a mountain range in Andalusia, Spain * Sierra Madre (other), various mountain ranges ** Sierra Madre (Philippines), a mountain range in the east of Luzon, Philippines * Sierra mountains (other) * Sierra Nevada, a mountain range in the U.S. states of California and Nevada * Sierra Nevada (Spain), a mountain range in Andalusia, Spain * Sierra de San Pedro Mártir, a mountain range in Baja California, Mexico * Sierra Maestra, a mountain range in Cuba Other places Africa * Sierra Leone, a country located on the coast of West Africa Asia * Sierra Bullones, Bohol, Philippines Europe * Sierra Nevada National Park (Spain), Andalusia, Spain * Sierra Nevada Observatory, Granada, Spain North America * High Sierra Trail, California, United State ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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