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Forearc Basins
A forearc is a region in a subduction zone between an oceanic trench and the associated volcanic arc. Forearc regions are present along convergent margins and eponymously form 'in front of' the volcanic arcs that are characteristic of convergent plate margins. A back-arc region is the companion region behind the volcanic arc. Many forearcs have an accretionary wedge which may form a topographic ridge known as an outer arc ridge that parallels the volcanic arc. A forearc basin between the accretionary wedge and the volcanic arc can accumulate thick deposits of sediment, sometimes referred to as an outer arc trough. Due to collisional stresses as one tectonic plate subducts under another, forearc regions are sources for powerful earthquakes. Formation During subduction, an oceanic plate is thrust below another tectonic plate, which can be oceanic or continental. Water and other volatiles in the subducting plate cause flux melting in the upper mantle, creating magma that rises and p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cross-section Of A Subduction Zone And Back-arc Basin
Cross section may refer to: * Cross section (geometry) ** Cross-sectional views in architecture and engineering 3D *Cross section (geology) * Cross section (electronics) * Radar cross section, measure of detectability * Cross section (physics) **Absorption cross section **Nuclear cross section **Neutron cross section **Photoionisation cross section **Gamma ray cross section * ''Cross Section'' (album), 1956 musical album by Billy Taylor See also * Cross section (fiber), microscopic view of textile fibers. *Section (fiber bundle), in differential and algebraic geometry and topology, a section of a fiber bundle or sheaf *Cross-sectional data, in statistics, econometrics, and medical research, a data set drawn from a single point in time **Cross-sectional study, a scientific investigation utilizing cross-sectional data ***Cross-sectional regression In statistics and econometrics, a cross-sectional regression is a type of Regression analysis, regression in which the Dependent and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eclogite
Eclogite () is a metamorphic rock containing garnet ( almandine- pyrope) hosted in a matrix of sodium-rich pyroxene ( omphacite). Accessory minerals include kyanite, rutile, quartz, lawsonite, coesite, amphibole, phengite, paragonite, zoisite, dolomite, corundum and, rarely, diamond. The chemistry of primary and accessory minerals is used to classify three types of eclogite (A, B, and C). The broad range of eclogitic compositions has led to a longstanding debate on the origin of eclogite xenoliths as subducted, altered oceanic crust. The name ''eclogite'' is derived from the Ancient Greek word for 'choice' (, ), meaning 'chosen rock' on account of its perceived beauty. It was first named by René Just Haüy in 1822 in the second edition of his work ''Traité de minéralogie''. Origins Eclogites typically result from high to ultrahigh pressure metamorphism of mafic rock at low thermal gradients of < as it is subducted to the lower crust to |
Back-arc Region
The back-arc region is the area behind a volcanic arc. In island volcanic arcs, it consists of back-arc basins of oceanic crust with abyssal depths, which may be separated by remnant arcs, similar to island arcs. In continental arcs, the back-arc region is part of the continental platform, either dry land ( subaerial) or forming shallow marine basins. Formation Back-arc deformation is a product of subduction at convergent plate tectonic boundaries. It initiates and evolves behind the volcanic arc on the overriding plate of a subduction zone. The stresses responsible for the deformation in this region of a subduction zone result from a combination of processes. The absolute motion of the upper plate as it moves towards or away from the trench strongly contributes to deformation in the back-arc region. Since the downgoing slab is partly anchored in the viscous layers of the mantle, and therefore its lateral movement is significantly slower than the surface plate, then any motion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cordillera Occidental (Bolivia)
Topographic map of Bolivia showing (east to west) plains of Cordill.html" ;"title="Geology of Bolivia#Lowlands and Sub-Andean zone">Sub-Andean Zone in red, Cordillera Oriental (Bolivia)">Eastern Cordillera in white, Altiplano in gray, and Western Cordillera in white The Cordillera Occidental or Western Cordillera of Bolivia is part of the Andes (that is also part of the American Cordillera), a mountain range characterized by volcanic activity, making up the natural border with Chile and starting in the north with Juqhuri and ending in the south at the Licancabur volcano, which is on the southern limit of Bolivia with Chile. The border goes through the innominated point located at two-thirds of elevation of Licancabur's northeastern slope at the southwestermost point of Bolivia at 22° 49' 41" south and 67° 52' 35" west. The climate of the region is cold and inadequate for animal and plant life. Its main feature is its ground, in which are large quantities of metallic minerals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithosphere
A lithosphere () is the rigid, outermost rocky shell of a terrestrial planet or natural satellite. On Earth, it is composed of the crust and the lithospheric mantle, the topmost portion of the upper mantle that behaves elastically on time scales of up to thousands of years or more. The crust and upper mantle are distinguished on the basis of chemistry and mineralogy. Earth's lithosphere Earth's lithosphere, which constitutes the hard and rigid outer vertical layer of the Earth, includes the crust and the lithospheric mantle (or mantle lithosphere), the uppermost part of the mantle that is not convecting. The layer below the lithosphere is called the asthenosphere, which is the weaker, hotter, and deeper part of the upper mantle that is able to convect. The lithosphere–asthenosphere boundary is defined by a difference in response to stress. The lithosphere remains rigid for very long periods of geologic time in which it deforms elastically and through brittle f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mud Volcano
A mud volcano or mud dome is a landform created by the eruption of mud or Slurry, slurries, water and gases. Several geological processes may cause the formation of mud volcanoes. Mud volcanoes are not true Igneous rock, igneous volcanoes as they do not produce lava and are not necessarily driven by magmatic activity. Mud volcanoes may range in size from merely 1 or 2 meters high and 1 or 2 meters wide, to 700 meters high and 10 kilometers wide. Smaller mud exudations are sometimes referred to as mud-pots. The mud produced by mud volcanoes is mostly formed as hot water, which has been heated deep below the Earth's surface, begins to mix and blend with subterranean mineral deposits, thus creating the mud slurry exudate. This material is then forced upwards through a geological fault or fissure due to local subterranean pressure imbalances. Mud volcanoes are associated with subduction zones and about 1100 have been identified on or near land. The temperature of any given active mu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Types Of Forearcs
Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * Type (Unix), a command in POSIX shells that gives information about commands. * Type safety, the extent to which a programming language discourages or prevents type errors. * Type system, defines a programming language's response to data types. Mathematics * Type (model theory) * Type theory, basis for the study of type systems * Arity or type, the number of operands a function takes * Type, any proposition or set in the intuitionistic type theory * Type, of an entire function ** Exponential type Biology * Type (biology), which fixes a scientific name to a taxon * Dog type, categorization by use or function of domestic dogs Lettering * Type is a design concept for lettering used in typography which helped bring about modern textual pri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnitogorsk
Magnitogorsk ( rus, Магнитого́рск, p=məɡnʲɪtɐˈɡorsk, ) is an industrial city in Chelyabinsk Oblast, Russia, on the eastern side of the extreme southern extent of the Ural Mountains by the Ural River. Its population is currently . Magnitogorsk was named after Magnetic Mountain, Mount Magnitnaya, a geological anomaly that once consisted almost completely of iron ore, around 55% to 60% iron. It is the second-largest city in Russia that is not the administrative centre of any federal subjects of Russia, federal subject or raion#Administrative districts, district. Magnitogorsk contains the largest iron and steel works in the country: Magnitogorsk Iron and Steel Works. The official motto of the city is "the place where Europe and Asia meet", as the city occupies land in both Europe and Asia. Magnitogorsk is one of only two planned Socialist realism, socialist realist settlements ever built (the other being Nowa Huta in Poland). History Foundation Magnitogorsk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olistostrome
An olistostrome is a sedimentary deposit composed of a chaotic mass of heterogeneous material, such as blocks and mud, known as olistoliths, that accumulates as a semifluid body by submarine (geology), submarine gravity sliding or Slump (geology), slumping of the unconsolidated sediments. It is a mappable stratigraphy, stratigraphic unit which lacks true bed (geology), bedding, but is intercalation (geology), intercalated amongst normal bed (geology), bedding sequence (geology), sequences, as in the Cenozoic Structural basin, basin of central Sicily. The term olistostrome is derived from the Greek ''olistomai'' (to slide) and ''stroma'' (accumulation).Ernesto Abbate, et al., "Olistostromes and olistoliths", ''Sedimentary Geology (journal), Sedimentary Geology'', 4 (1970), 521-557. See also *Submarine landslide References [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synsedimentary Fold
In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved (''"folded"'') during permanent deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds. They occur as single isolated folds or in periodic sets (known as ''fold trains''). Synsedimentary folds are those formed during sedimentary deposition. Folds form under varied conditions of stress, pore pressure, and temperature gradient, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks. A set of folds distributed on a regional scale constitutes a fold belt, a common feature of orogenic zones. Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (''fault bend fold''), at the tip of a propagating fault (''fault propagation fold''), by differential compac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc-continent
A continental arc is a type of volcanic arc occurring as an "arc-shape" Topography, topographic high region along a continental margin. The continental arc is formed at an active continental margin where two tectonic plates meet, and where one plate has continental crust and the other oceanic crust along the line of plate convergence, and a subduction zone develops. The magmatism and petrogenesis of continental crust are complicated: in essence, continental arcs reflect a mixture of oceanic crust materials, mantle wedge and continental crust materials. Origin When two tectonic plates collide, relatively denser oceanic crust will be subducted under relatively lighter continental crust. Because of the subduction process, the relatively cooler oceanic crust, along with water, is subducted to the asthenosphere, where pressures and temperatures are much higher than the surface of Earth. Under such conditions, the downgoing plate releases Volatile (astrogeology)#Igneous petrology, volati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orogenesis
Orogeny () is a mountain-building process that takes place at a convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is uplifted to form one or more mountain ranges. This involves a series of geological processes collectively called orogenesis. These include both structural deformation of existing continental crust and the creation of new continental crust through volcanism. Magma rising in the orogen carries less dense material upwards while leaving more dense material behind, resulting in compositional differentiation of Earth's lithosphere ( crust and uppermost mantle). A synorogenic (or synkinematic) process or event is one that occurs during an orogeny. The word ''orogeny'' comes . Although it was used before him, the American geologist G. K. Gilbert used the term in 1890 to mean the process of mountain-building, as distinguished from epeirogeny. Tectonics Orogeny takes place on the convergent margi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
