|
Detachment Fault
A detachment fault is a gently dipping normal fault associated with large-scale extensional tectonics. Detachment faults often have very large displacements (tens of km) and juxtapose unmetamorphosed hanging walls against medium to high-grade metamorphic footwalls that are called metamorphic core complexes. They are thought to have formed as either initially low-angle structures or by the rotation of initially high-angle normal faults modified also by the isostatic effects of tectonic denudation. They may also be called denudation faults. Examples of detachment faulting include: *The Snake Range detachment system of the Basin and Range Province of western North America which was active during the Miocene *The Nordfjord-Sogn detachment of western Norway active during the Devonian Period *The Whipple detachment in southeastern California Detachment faults have been found on the sea floor close to divergent plate boundaries characterised by a limited supply of upwelling magma, su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
View Of Doso Doyabi From Wheeler Peak
A view is a sight or prospect or the ability to see or be seen from a particular place. View, views or Views may also refer to: Common meanings * View (Buddhism), a charged interpretation of experience which intensely shapes and affects thought, sensation, and action * Graphical projection in a technical drawing or schematic ** Multiview orthographic projection, standardizing 2D images to represent a 3D object * Opinion, a belief about subjective matters * Page view, a visit to a World Wide Web page * Panorama, a wide-angle view * Scenic viewpoint, an elevated location where people can view scenery * World view, the fundamental cognitive orientation of an individual or society encompassing the entirety of the individual or society's knowledge and point-of-view Places * View, Kentucky, an unincorporated community in Crittenden County * View, Texas, an unincorporated community in Taylor County Arts, entertainment, and media Music * ''View'' (album), the 2003 debut album by ... [...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] |
Peridotite
Peridotite ( ) is a dense, coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium (Mg2+), reflecting the high proportions of magnesium-rich olivine, with appreciable iron. Peridotite is derived from Earth's mantle, either as solid blocks and fragments, or as crystals accumulated from magmas that formed in the mantle. The compositions of peridotites from these layered igneous complexes vary widely, reflecting the relative proportions of pyroxenes, chromite, plagioclase, and amphibole. Peridotite is the dominant rock of the upper part of Earth's mantle. The compositions of peridotite nodules found in certain basalts are of special interest along with diamond pipes (kimberlite), because they provide samples of Earth's mantle brought up from depths ranging from about 30 km to 200 km or more. Some of the nodules preserve isotope ratios of osm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gabbro
Gabbro () is a phaneritic (coarse-grained), mafic intrusive igneous rock formed from the slow cooling of magnesium-rich and iron-rich magma into a holocrystalline mass deep beneath the Earth's surface. Slow-cooling, coarse-grained gabbro is chemically equivalent to rapid-cooling, fine-grained basalt. Much of the Earth's oceanic crust is made of gabbro, formed at mid-ocean ridges. Gabbro is also found as plutons associated with continental volcanism. Due to its variant nature, the term ''gabbro'' may be applied loosely to a wide range of intrusive rocks, many of which are merely "gabbroic". By rough analogy, gabbro is to basalt as granite is to rhyolite. Etymology The term "gabbro" was used in the 1760s to name a set of rock types that were found in the ophiolites of the Apennine Mountains in Italy. It was named after Gabbro, a hamlet near Rosignano Marittimo in Tuscany. Then, in 1809, the German geologist Christian Leopold von Buch used the term more restrictively in his descri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spreading Ridge
A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a divergent plate boundary. The rate of seafloor spreading determines the morphology of the crest of the mid-ocean ridge and its width in an ocean basin. The production of new seafloor and oceanic lithosphere results from mantle upwelling in response to plate separation. The melt rises as magma at the linear weakness between the separating plates, and emerges as lava, creating new oceanic crust and lithosphere upon cooling. The first discovered mid-ocean ridge was the Mid-Atlantic Ridge, which is a spreading center that bisects the North and South Atlantic basins; hence the origin of the name 'mid-ocean ridge'. Most oceanic spreading centers are not in the middle of their hosting ocean basis but regardless, are traditionally called mid-ocean rid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isostatic Uplift
Post-glacial rebound (also called isostatic rebound or crustal rebound) is the rise of land masses after the removal of the huge weight of ice sheets during the last glacial period, which had caused isostatic depression. Post-glacial rebound and isostatic depression are phases of glacial isostasy (glacial isostatic adjustment, glacioisostasy), the deformation of the Earth's crust in response to changes in ice mass distribution. The direct raising effects of post-glacial rebound are readily apparent in parts of Northern Eurasia, Northern America, Patagonia, and Antarctica. However, through the processes of ''ocean siphoning'' and ''continental levering'', the effects of post-glacial rebound on sea level are felt globally far from the locations of current and former ice sheets.Milne, G.A., and J.X. Mitrovica (2008) ''Searching for eustasy in deglacial sea-level histories.'' Quaternary Science Reviews. 27:2292–2302. Overview During the last glacial period, much of northern Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brecciated
Breccia () is a rock composed of large angular broken fragments of minerals or rocks cemented together by a fine-grained matrix. The word has its origins in the Italian language, in which it means "rubble". A breccia may have a variety of different origins, as indicated by the named types including sedimentary breccia, tectonic breccia, igneous breccia, impact breccia, and hydrothermal breccia. A megabreccia is a breccia composed of very large rock fragments, sometimes kilometers across, which can be formed by landslides, impact events, or caldera collapse. Types Breccia is composed of coarse rock fragments held together by cement or a fine-grained matrix. Like conglomerate, breccia contains at least 30 percent of gravel-sized particles (particles over 2mm in size), but it is distinguished from conglomerate because the rock fragments have sharp edges that have not been worn down. These indicate that the gravel was deposited very close to its source area, since otherwise th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures and pressures than schist. Gneiss nearly always shows a banded texture characterized by alternating darker and lighter colored bands and without a distinct cleavage. Gneisses are common in the ancient crust of continental shields. Some of the oldest rocks on Earth are gneisses, such as the Acasta Gneiss. Description Orthogneiss from the Czech Republic In traditional English and North American usage, a gneiss is a coarse-grained metamorphic rock showing compositional banding (gneissic banding) but poorly developed schistosity and indistinct cleavage. In other words, it is a metamorphic rock composed of mineral grains easily seen with the unaided eye, which form obvious compositional layers, but which has only a weak tendency to fracture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mylonite
Mylonite is a fine-grained, compact metamorphic rock produced by dynamic recrystallization of the constituent minerals resulting in a reduction of the grain size of the rock. Mylonites can have many different mineralogical compositions; it is a classification based on the textural appearance of the rock. Formation Mylonites are ductilely deformed rocks formed by the accumulation of large shear strain, in ductile fault zones. There are many different views on the formation of mylonites, but it is generally agreed that crystal-plastic deformation must have occurred, and that fracturing and cataclastic flow are secondary processes in the formation of mylonites. Mechanical abrasion of grains by milling does not occur, although this was originally thought to be the process that formed mylonites, which were named from the Greek μύλος ''mylos'', meaning mill. Mylonites form at depths of no less than 4 km. There are many different mechanisms that accommodate crystal-plastic def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mormon Mountains
The Mormon Mountains are located in Lincoln and Clark counties in Nevada, between 16 and northwest of Mesquite on I–15 in the Virgin Valley, east of the Meadow Valley Mountains and Meadow Valley and northeast of Moapa Valley.''Overton, Nevada–Arizona'', 30x60 Minute Topographic Quadrangle, USGS, 1987 The highest point in the range is Mormon Peak, at above sea level.''Moapa Peak NW, Nevada,'' 7.5 Minute Quadrangle, USGS, 1969 Another smaller mountain range lies to the east, called the East Mormon Mountains. The south fork of the Toquop Wash drains the east side of the range and continues on through the N–S linear ridge of the East Mormon Mountains. The mountains fall under the jurisdiction of the Bureau of Land Management (BLM) and cover approximately . The Mormon Mountains are home to several different species of lizards, and ground snakes, toads and bullfrogs can be found in the region. The lower elevations of the range are mostly shrublands, but at higher elevations one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yerington
Yerington is a city in Lyon County, Nevada, United States. The population was 3,048 at the 2010 census. It is the current county seat of Lyon County, with the first county seat having been established at Dayton on November 29, 1861. It is named after Henry M. Yerington, superintendent of the Virginia and Truckee Railroad from 1868 to 1910. History Native people The Yerington Paiute Tribe of the Yerington Colony and Campbell Ranch is headquartered in Yerington. The people, known as ''Namu'' (human beings) in their own language, have lived in the Smith and Mason Valleys in Northwestern Nevada, since around 1000 A.D. City The community was formerly named Greenfield, Mason Valley, and Pizen Switch (irreverent nickname from the time where Yerington was a transfer - or switch - stop; and the local whiskey was so bad that it was called "poison". "Poison" came out sounding like "pizen" because of local vernacular, and the name "Pizen Switch" stuck.) It was founded on August 6, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
