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Valais Ocean
The Valais Ocean is a subducted oceanic basin which was situated between the continent Europe and the microcontinent Iberia or so called Briançonnais microcontinent. Remnants of the Valais ocean are found in the western Alps and in tectonic windows of the eastern Alps and are mapped as the so-called "north Penninic" nappes. Tectonic history After the breakup of Pangaea in the early Mesozoic age, the continents of Africa, South America, Europe and North America began to move away from each other. The breaking up, or rifting, did not take place along one unbroken line; thus, at the southern edge of the European plate the microcontinent Iberia also began to break away from Europe. In the western part of the rift that separated the two landmasses, oceanic crust was formed in what is at present the Gulf of Biscay, while in the eastern part the Valais Ocean was formed. When in the Cretaceous period Africa again began to move towards Europe, the Valais Ocean became sandwiched between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oceanic Crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates. It is composed of the upper oceanic crust, with pillow lavas and a dike complex, and the lower oceanic crust, composed of troctolite, gabbro and ultramafic cumulates. The crust overlies the rigid uppermost layer of the mantle. The crust and the rigid upper mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium. It is thinner than continental crust, or sial, generally less than 10 kilometers thick; however, it is denser, having a mean density of about 3.0 grams per cubic centimeter as opposed to continental crust which has a density of about 2.7 grams per cubic centimeter. The crust uppermost is the result of the cooling of magma derived from mantle material below the plate. The magma is injected into the spreading center, which consists mainly of a partly solidified crystal mush derived from earlier ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alps
The Alps () ; german: Alpen ; it, Alpi ; rm, Alps ; sl, Alpe . are the highest and most extensive mountain range system that lies entirely in Europe, stretching approximately across seven Alpine countries (from west to east): France, Switzerland, Italy, Liechtenstein, Austria, Germany, and Slovenia. The Alpine arch generally extends from Nice on the western Mediterranean to Trieste on the Adriatic and Vienna at the beginning of the Pannonian Basin. The mountains were formed over tens of millions of years as the African and Eurasian tectonic plates collided. Extreme shortening caused by the event resulted in marine sedimentary rocks rising by thrusting and folding into high mountain peaks such as Mont Blanc and the Matterhorn. Mont Blanc spans the French–Italian border, and at is the highest mountain in the Alps. The Alpine region area contains 128 peaks higher than . The altitude and size of the range affect the climate in Europe; in the mountains, precipitation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basalt
Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial planet, rocky planet or natural satellite, moon. More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt is chemically equivalent to slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. Basalt is also an important rock type on other planetary bodies in the Solar System. For example, the bulk of the plains of volcanism on Venus, Venus, which cover ~80% of the surface, are basaltic; the lunar mare, lunar maria are plains of flood-basaltic lava flows; and basalt is a common rock on the surface of Mars. Molten basalt lava has a low viscosity due to its relatively low silica content (between 45% and 52%), resulting in rapidly moving lava flo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Turbidite
A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites were first properly described by Arnold H. Bouma (1962), who studied deepwater sediments and recognized particular "fining-up intervals" within deep water, fine-grained shales, which were anomalous because they started at pebble conglomerates and terminated in shales. This was anomalous because within the deep ocean it had historically been assumed that there was no mechanism by which tractional flow could carry and deposit coarse-grained sediments into the abyssal depths. Bouma cycles begin with an erosional contact of a coarse lower bed of pebble to granule conglomerate in a sandy matrix, and grade up through coarse then medium plane parallel sandstone; through cross-bedded sandstone; rippled cross-bedded sand/silty sand, and finally lami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiolarite
Radiolarite is a Siliceous ooze, siliceous, comparatively hard, fine-grained, chert-like, and homogeneous sedimentary rock that is composed predominantly of the microscopic remains of radiolarians. This term is also used for Friability, indurated radiolarian oozes and sometimes as a synonym of radiolarian earth. However, radiolarian earth is typically regarded by Earth scientists to be the unconsolidated equivalent of a radiolarite. A radiolarian chert is well-bedded, microcrystalline radiolarite that has a well-developed siliceous cement or groundmass.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackson, J.A., eds. (2005) ''Glossary of Geology'' (5th ed.). Alexandria, Virginia, American Geological Institute. 779 pp. Mineralogy and petrology Radiolarites are biogenic, marine, finely layered sedimentary rocks. The layers reveal an interchange of clastic mica grains, radiolarian tests, carbonates and organic pigments. Clay minerals are usually not abundant. Radiolarites deposit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Window (geology)
350px, Schematic overview of a thrust system. The hanging wall block is (when it has reasonable proportions) called a nappe. If an erosional hole is created in the nappe that is called a window. A klippe">erosion.html" ;"title="nappe. If an erosion">nappe. If an erosional hole is created in the nappe that is called a window. A klippe is a solitary outcrop of the nappe in the middle of autochthonous material. A tectonics, tectonic window, or fenster (lit. "window" in German language, German), is a geology, geologic structure formed by erosion or normal faulting on a thrust fault, thrust system. In such a system the rock mass ( fault (geology), hanging wall block) that has been transported by movement along the thrust is called a nappe. When erosion or normal faulting produces a hole in the nappe where the underlying autochthonous (i.e. un-transported) rocks crop out this is called a window. Klippen are also a feature near windows. The klippe is the remnant portion of a nappe aft ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology Of The Alps
The Alps form part of a Cenozoic orogenic belt of mountain chains, called the Alpide belt, that stretches through southern Europe and Asia from the Atlantic all the way to the Himalayas. This belt of mountain chains was formed during the Alpine orogeny. A gap in these mountain chains in central Europe separates the Alps from the Carpathians to the east. Orogeny took place continuously and tectonic subsidence has produced the gaps in between. The Alps arose as a result of the collision of the African and Eurasian tectonic plates, in which the Alpine Tethys, which was formerly in between these continents, disappeared. Enormous stress was exerted on sediments of the Alpine Tethys basin and its Mesozoic and early Cenozoic strata were pushed against the stable Eurasian landmass by the northward-moving African landmass. Most of this occurred during the Oligocene and Miocene epochs. The pressure formed great recumbent folds, or ''nappes'', that rose out of what had been the Alp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Valais
Valais ( , , ; frp, Valês; german: Wallis ), more formally the Canton of Valais,; german: Kanton Wallis; in other official Swiss languages outside Valais: it, (Canton) Vallese ; rm, (Chantun) Vallais. is one of the cantons of Switzerland, 26 cantons forming the Switzerland, Swiss Confederation. It is composed of thirteen districts and its capital and largest city is Sion, Switzerland, Sion. The flag of the canton is made of thirteen stars representing the districts, on a white-red background. Valais is situated in the southwestern part of Switzerland, the country. It borders the cantons of Canton of Vaud, Vaud and Canton of Bern, Bern to the north, the cantons of Canton of Uri, Uri and Ticino to the east, as well as Italy to the south and France to the west. It is one of the three large southern Alps, Alpine cantons, along with Ticino and the Grisons, which encompass a vast diversity of ecosystems. It is a bilingual canton, French language, French and German language, German ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cantons Of Switzerland
The 26 cantons of Switzerland (german: Kanton; french: canton ; it, cantone; Sursilvan and Surmiran: ; Vallader and Puter: ; Sutsilvan: ; Rumantsch Grischun: ) are the member states of the Swiss Confederation. The nucleus of the Swiss Confederacy in the form of the first three confederate allies used to be referred to as the . Two important periods in the development of the Old Swiss Confederacy are summarized by the terms ('Eight Cantons'; from 1353–1481) and ('Thirteen Cantons', from 1513–1798).rendered "the 'confederacy of eight'" and "the 'Thirteen-Canton Confederation'", respectively, in: Each canton of the Old Swiss Confederacy, formerly also ('lieu/locality', from before 1450), or ('estate', from ), was a fully sovereign state with its own border controls, army, and currency from at least the Treaty of Westphalia (1648) until the establishment of the Swiss federal state in 1848, with a brief period of centralised government during the Helvetic Republic ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switzerland
). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel, St. Gallen a.o.). , coordinates = , largest_city = Zürich , official_languages = , englishmotto = "One for all, all for one" , religion_year = 2020 , religion_ref = , religion = , demonym = , german: Schweizer/Schweizerin, french: Suisse/Suissesse, it, svizzero/svizzera or , rm, Svizzer/Svizra , government_type = Federalism, Federal assembly-independent Directorial system, directorial republic with elements of a direct democracy , leader_title1 = Federal Council (Switzerland), Federal Council , leader_name1 = , leader_title2 = , leader_name2 = Walter Thurnherr , legislature = Fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Penninic Nappes
The Penninic nappes or the Penninicum, commonly abbreviated as Penninic, are one of three nappe stacks and geological zones in which the Alps can be divided. In the western Alps the Penninic nappes are more obviously present than in the eastern Alps (in Austria), where they crop out as a narrow band. The name ''Penninic'' is derived from the Pennine Alps, an area in which rocks from the Penninic nappes are abundant. Of the three nappe stacks the Penninic nappes have the highest metamorphic grade. They contain high grade metamorphic rocks of different paleogeographic origins. They were deposited as sediments on the crust that existed between the European and Apulian plates before the Alps were formed. They are characteristically ophiolite sequences and deep marine sediments, metamorphosed to phyllites, schists and amphibolites. Middle Penninic nappes include the Monte Rosa, Mont Fort, Siviez-Mischabel, Cimes Blanches and Frilihorn, of European origin. Upper Penninic nappes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophiolite
An ophiolite is a section of Earth's oceanic crust and the underlying upper mantle that has been uplifted and exposed above sea level and often emplaced onto continental crustal rocks. The Greek word ὄφις, ''ophis'' (''snake'') is found in the name of ophiolites, because of the superficial texture of some of them. Serpentinite especially evokes a snakeskin. The suffix ''lite'' from the Greek ''lithos'' means "stone". Some ophiolites have a green color. The origin of these rocks, present in many mountainous massifs, remained uncertain until the advent of plate tectonic theory. Their great significance relates to their occurrence within mountain belts such as the Alps and the Himalayas, where they document the existence of former ocean basins that have now been consumed by subduction. This insight was one of the founding pillars of plate tectonics, and ophiolites have always played a central role in plate tectonic theory and the interpretation of ancient mountain belts. Pse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
