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Sierra De Gredos
The Sierra de Gredos is a mountain range in central Spain that spans the provinces of Ávila, Salamanca, Cáceres, Madrid, and Toledo. It is part of the much larger Sistema Central of mountain ranges. Its highest point is Pico Almanzor, at 2,592 metres and it has been declared a natural park by the Autonomous Community of Castile and León. The Sierra de Gredos is one of the most extensive mountain ranges of the Central System; it comprises five river valleys: the Alto Tormes, the Alto Alberche, the Tiétar Oriental, the Tiétar Occidental y la Vera, and the Valle del Ambroz. The first known inhabitants were the Vettones, a pre-Roman Celtic people. The central part of the range encomprises the Sierra de Gredos Regional Park. Geology The Sierra de Gredos comprises mainly granite, which is a common type of intrusive, felsic, igneous rock which is granular and phaneritic in texture. This rock consists mainly of quartz, mica, and feldspar. In some Gredos rocks the feldspar cryst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sierra De Gredos Regional Park
Sierra de Gredos Regional Park (in Spanish "''Parque Regional de la Sierra de Gredos''") is a protected natural area in Spain, covering 86,397 hectares. The estimated population within the socio-economic influence area is 21,182. The law that declared the status of the park was published in the BOE on July 22, 1996. Location The park, located in the southern end of the province of Ávila, in the autonomous community of Castile and León, contains a great part of the Sierra de Gredos mountain range. Sierra de Gredos is the highest sub-range of the Sistema Central main range. The highest mountain, Almanzor Peak, which is high, is one of the summits towering around the Gredos glacial cirque ("'' Circo de Gredos''"). The area of the park includes territory that belongs to the next municipalities: El Arenal, Ávila, Arenas de San Pedro, Bohoyo, Candeleda, La Carrera, Cuevas del Valle, Gil García, Guisando, El Hornillo, Hoyos del Collado, Hoyos del Espino, Los Llanos de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iberian Peninsula
The Iberian Peninsula (), ** * Aragonese and Occitan: ''Peninsula Iberica'' ** ** * french: Péninsule Ibérique * mwl, Península Eibérica * eu, Iberiar penintsula also known as Iberia, is a peninsula in southwestern Europe, defining the westernmost edge of Eurasia. It is principally divided between Spain and Portugal, comprising most of their territory, as well as a small area of Southern France, Andorra, and Gibraltar. With an area of approximately , and a population of roughly 53 million, it is the second largest European peninsula by area, after the Scandinavian Peninsula. Name Greek name The word ''Iberia'' is a noun adapted from the Latin word "Hiberia" originating in the Ancient Greek word Ἰβηρία ('), used by Greek geographers under the rule of the Roman Empire to refer to what is known today in English as the Iberian Peninsula. At that time, the name did not describe a single geographical entity or a distinct population; the same name was us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vettones
The Vettones (Greek: ''Ouettones'') were a pre-Roman people of the Iberian Peninsula of possibly Celtic ethnicity. Origins Lujan (2007) concludes that some of the names of the Vettones show clearly western Hispano-Celtic features. Reissued in 2012 in softcover as . A Celtiberian origin has also been claimed. Organized since the 3rd Century BC, the Vettones formed a tribal confederacy of undetermined strength. Even though their tribes' names are obscure, the study of local epigraphic evidence has identified the Calontienses, Coerenses, Caluri, Bletonesii and Seanoci, but the others remain unknown. Culture A predominately horse- and cattle-herder people that practiced transhumance, archeology has identified them with the local 2nd Iron Age ‘Cogotas II’ Culture, also known as the ‘Culture of the Verracos’ ('' verracos de piedra''), named after the crude granite sculptures representing pigs, wild boars and bulls that still dot their former region. These are one of th ... [...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] |
Magma
Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals and gas bubbles. Magma is produced by melting of the mantle or the crust in various tectonic settings, which on Earth include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Mantle and crustal melts migrate upwards through the crust where they are thought to be stored in magma chambers or trans-crustal crystal-rich mush zones. During magma's storage in the crust, its composition may be modified by fractional crystallization, contamination with crustal melts, magma mixing, and degassing. Following its ascent through the crust, magma may feed a volcano and be extruded as lava, or it may solidify underground to form an intrusion, such as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Variscan Orogeny
The Variscan or Hercynian orogeny was a geologic mountain-building event caused by Late Paleozoic continental collision between Euramerica (Laurussia) and Gondwana to form the supercontinent of Pangaea. Nomenclature The name ''Variscan'', comes from the Medieval Latin name for the district '' Variscia'', the home of a Germanic tribe, the Varisci; Eduard Suess, professor of geology at the University of Vienna, coined the term in 1880. (Variscite, a rare green mineral first discovered in the Vogtland district of Saxony in Germany, which is in the Variscan belt, has the same etymology.) ''Hercynian'', on the other hand, derives from the Hercynian Forest. Both words were descriptive terms of strike directions observed by geologists in the field, ''variscan'' for southwest to northeast, ''hercynian'' for northwest to southeast. The ''variscan'' direction reflected the direction of ancient fold belts cropping out throughout Germany and adjacent countries and the meaning shifted from d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tethys Ocean
The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period. It was preceded by the Paleo-Tethys Ocean, which lasted between the Cambrian and the Early Triassic, while the Neotethys formed during the Late Triassic and lasted until the early Eocene (about 50 million years ago) when it completely closed. A portion known as the Paratethys formed during the Late Jurassic, was isolated during the Oligocene (34 million years ago) and lasted up to the Pliocene (about 5 million years ago), when it largely dried out. Many major seas and lakes of Europe and Western Asia, including the Mediterranean Sea, the Black Sea, the Caspian Sea, and the Aral Sea are thought to be remnants of the Paratethys. Ety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic Era
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon. The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838 by combining the Greek words ''palaiós'' (, "old") and ''zōḗ'' (), "life", meaning "ancient life" ). It is the longest of the Phanerozoic eras, lasting from , and is subdivided into six geologic periods (from oldest to youngest): # Cambrian # Ordovician # Silurian # Devonian # Carboniferous # Permian The Paleozoic comes after the Neoproterozoic Era of the Proterozoic Eon and is followed by the Mesozoic Era. The Paleozoic was a time of dramatic geological, climatic, and evolutionary change. The Cambrian witnessed the most rapid and widespread diversification of life in Earth's history, known as the Cambrian explosion, in which most modern phyla first appeared. Arthropods, molluscs, fish, amphibians, reptiles, and synapsids all evolved during the Paleozoic. Life began in the oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphic Rocks
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causing profound physical or chemical changes. During this process, the rock remains mostly in the solid state, but gradually recrystallizes to a new texture or mineral composition. The protolith may be an igneous, sedimentary, or existing metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and form 12% of the Earth's land surface. They are classified by their protolith, their chemical and mineral makeup, and their texture. They may be formed simply by being deeply buried beneath the Earth's surface, where they are subject to high temperatures and the great pressure of the rock layers above. They can also form from tectonic processes such as continental collisions, which cause horizontal pressure, friction, and distort ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Granodiorite
Granodiorite () is a coarse-grained (phaneritic) intrusive igneous rock similar to granite, but containing more plagioclase feldspar than orthoclase feldspar. The term banatite is sometimes used informally for various rocks ranging from granite to diorite, including granodiorite. Composition According to the QAPF diagram, granodiorite has a greater than 20% quartz by volume, and between 65% and 90% of the feldspar is plagioclase. A greater amount of plagioclase would designate the rock as tonalite. Granodiorite is felsic to intermediate in composition. It is the intrusive igneous equivalent of the extrusive igneous dacite. It contains a large amount of sodium (Na) and calcium (Ca) rich plagioclase, potassium feldspar, quartz, and minor amounts of muscovite mica as the lighter colored mineral components. Biotite and amphiboles often in the form of hornblende are more abundant in granodiorite than in granite, giving it a more distinct two-toned or overall darker appearan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldspars and the ''alkali'' (potassium-sodium) feldspars. Feldspars make up about 60% of the Earth's crust, and 41% of the Earth's continental crust by weight. Feldspars crystalize from magma as both intrusive and extrusive igneous rocks and are also present in many types of metamorphic rock. Rock formed almost entirely of calcic plagioclase feldspar is known as anorthosite. Feldspars are also found in many types of sedimentary rocks. Compositions The feldspar group of minerals consists of tectosilicates, silicate minerals in which silicon ions are linked by shared oxygen ions to form a three-dimensional network. Compositions of major elements in common feldspars can be expressed in terms of three endmembers: * potassium feldspar (K-spar) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
