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Gravity Spreading
Gravity spreading is a phenomenon in which a geological body laterally extends and vertically contracts to reduce its gravitational potential energy.Schultz-Ela, D. D. (2001). Excursus on gravity gliding and gravity spreading. Journal of Structural Geology 23, p. 725-731. It has been observed on many different scales, and at numerous locations on Earth, from rhyolite lava flows to passive margins.Smith, J. V., Houston, E. C. (1994). Folds produced by gravity spreading of a banded rhyolite lava flow. Journal of Volcanology and Geothermal Research 63, p. 89-94.Rowan, M. G., Peel, F. J., Vendeville, B. C. (2004). Gravity-driven Fold Belts on Passive Margins. AAPG Memoir 82, p. 157-182 Additionally, gravity spreading is likely to have occurred on both Mars and Venus.Montgomery, D. R., Som, S. M., et al. (2009). Continental-scale salt tectonics on Mars and the origin of Valles Marineris and associated outflow channels. GSA Bulletin 121, p. 117-133Kozak, R. C., Schaber, G. G. (1986). Gravit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gravitational Potential Energy
Gravitational energy or gravitational potential energy is the potential energy an object with mass has due to the gravitational potential of its position in a gravitational field. Mathematically, it is the minimum Work (physics), mechanical work that has to be done against the gravitational force to bring a mass from a chosen reference point (often an "infinite distance" from the mass generating the field) to some other point in the field, which is equal to the change in the kinetic energy, kinetic energies of the objects as they Free fall, fall towards each other. Gravitational potential energy increases when two objects are brought further apart and is converted to kinetic energy as they are allowed to fall towards each other. Formulation For two pairwise interacting point particles, the gravitational potential energy U is the work that an outside agent must do in order to quasi-statically bring the masses together (which is therefore, exactly opposite the work done by the gravit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laramide Orogeny
The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 80 to 70 million years ago, and ended 55 to 35 million years ago. The exact duration and ages of beginning and end of the orogeny are in dispute. The Laramide orogeny occurred in a series of pulses, with quiescent phases intervening. The major feature that was created by this orogeny was deep-seated, thick-skinned deformation, with evidence of this orogeny found from Canada to northern Mexico, with the easternmost extent of the mountain-building represented by the Black Hills of South Dakota. The phenomenon is named for the Laramie Mountains of eastern Wyoming. The Laramide orogeny is sometimes confused with the Sevier orogeny, which partially overlapped in time and space. The orogeny is commonly attributed to events off the west coast of North America, where the Kula and Farallon Plates were sliding under the North American Plate. Most hypotheses propo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Downhill Creep
Downhill creep, also known as soil creep or commonly just creep, is a type of creep characterized by the slow, downward progression of rock and soil down a low grade slope; it can also refer to slow deformation of such materials as a result of prolonged pressure and stress. Creep may appear to an observer to be continuous, but it really is the sum of numerous minute, discrete movements of slope material caused by the force of gravity. Friction, being the primary force to resist gravity, is produced when one body of material slides past another offering a mechanical resistance between the two which acts to hold objects (or slopes) in place. As slope on a hill increases, the gravitational force that is perpendicular to the slope decreases and results in less friction between the material that could cause the slope to slide. Overview Water is a very important factor when discussing soil deformation and movement. For instance, a sandcastle will only stand up when it is made with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Creep (deformation)
In materials science, creep (sometimes called cold flow) is the tendency of a solid material to undergo slow deformation while subject to persistent mechanical stresses. It can occur as a result of long-term exposure to high levels of stress that are still below the yield strength of the material. Creep is more severe in materials that are subjected to heat for long periods and generally increases as they near their melting point. The rate of deformation is a function of the material's properties, exposure time, exposure temperature and the applied structural load. Depending on the magnitude of the applied stress and its duration, the deformation may become so large that a component can no longer perform its function – for example creep of a turbine blade could cause the blade to contact the casing, resulting in the failure of the blade. Creep is usually of concern to engineers and metallurgists when evaluating components that operate under high stresses or high temperatures ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tharsis
Tharsis () is a vast volcanic plateau centered near the equator in the western hemisphere of Mars. The region is home to the largest volcanoes in the Solar System, including the three enormous shield volcanoes Arsia Mons, Pavonis Mons, and Ascraeus Mons, which are collectively known as the Tharsis Montes. The tallest volcano on the planet, Olympus Mons, is often associated with the Tharsis region but is actually located off the western edge of the plateau. The name Tharsis is the Greco-Latin transliteration of the biblical Tarshish, the land at the western extremity of the known world. Location and size Tharsis can have many meanings depending on historical and scientific context. The name is commonly used in a broad sense to represent a continent-sized region of anomalously elevated terrain centered just south of the equator around longitude 265°E.Carr, M.H. (2006). ''The Surface of Mars;'' Cambridge University Press: Cambridge, UK, p. 46. . Called the Tharsis bulge or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thaumasia Plateau
The Thaumasia Plateau is a vast sloping volcanic plain in the western hemisphere of Mars, and is the most extensive component of the Tharsis Rise by area. Syria Planum, Solis Planum, Sinai Planum, and Thaumasia Planum are the constituent sectors of the plateau, which sits between 8 km and 4 km above the surrounding southern highlands. It is bounded by vestigial basement terrains that predate the formation of Tharsis. This area has been proposed to be a drainage basin that sourced the floodwaters forming the outflow channels surrounding Chryse Planitia. Context The Thaumasia Plateau lies at the heart of the Tharsis Rise, and is framed to the northwest by the Noctis Labyrinthus fracture zone and the Valles Marineris chasmata (particularly, Ius Chasma, Melas Chasma, and Coprates Chasma, from northwest to northeast). Older Noachian basement crust, likely predating the formation of Tharsis, bound the Thaumasia Plateau to the west ( Claritas Rise and the Claritas Fossa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New South Wales
New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South Australia to the west. Its coast borders the Coral Sea, Coral and Tasman Seas to the east. The Australian Capital Territory and Jervis Bay Territory are Enclave and exclave, enclaves within the state. New South Wales' state capital is Sydney, which is also Australia's most populous city. , the population of New South Wales was over 8.3 million, making it Australia's most populous state. Almost two-thirds of the state's population, 5.3 million, live in the Greater Sydney area. The Colony of New South Wales was founded as a British penal colony in 1788. It originally comprised more than half of the Australian mainland with its Western Australia border, western boundary set at 129th meridian east in 1825. The colony then also includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Décollement
Décollement () is a gliding plane between two rock masses, also known as a basal detachment fault. Décollements are a Deformation (geology), deformational structure, resulting in independent styles of deformation in the rocks above and below the fault. They are associated with both compressional settings (involving Fold (geology), folding and Obduction, overthrusting) and extensional settings. Origin The term was first used by geologists studying the structure of the Swiss Jura Mountains, coined in 1907 by A. Buxtorf, who released a paper that theorized that the Jura is the frontal part of a décollement at the base of a nappe, rooted in the faraway Swiss Alps. Marcel Alexandre Bertrand published a paper in 1884 that dealt with Geology of the Alps, Alpine nappism. Thin-skinned deformation, Thin-skinned tectonics was implied in that paper but the actual term was not used until Buxtorf's 1907 publication. Formation Décollements are caused by surface forces, which 'push' at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcano
A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions."Mid-ocean ridge tectonics, volcanism and geomorphology." Geology 26, no. 455 (2001): 458. https://macdonald.faculty.geol.ucsb.edu/papers/Macdonald%20Mid-Ocean%20Ridge%20Tectonics.pdf Volcanoes can also form where there is str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bighorn Basin
The Bighorn Basin is a plateau region and intermontane basin, approximately 100 miles (160 km) wide, in north-central Wyoming in the United States. It is bounded by the Absaroka Range on the west, the Pryor Mountains on the north, the Bighorn Mountains on the east, and the Owl Creek Mountains and Bridger Mountains (Wyoming), Bridger Mountains on the south. It is drained to the north by tributaries of the Bighorn River, which enters the basin from the south, through a gap between the Owl Creek and Bridger Mountains, as the Wind River (Wyoming), Wind River, and becomes the Bighorn as it enters the basin. The region is semi-arid, receiving only 6–10 in (15–25 cm) of rain annually. The largest cities in the basin include the Wyoming towns of Cody, Wyoming, Cody, Thermopolis, Wyoming, Thermopolis, Worland, Wyoming, Worland, and Powell, Wyoming, Powell. Sugar beets, pinto beans, sunflowers, barley, oats, corn and alfalfa hay are grown on irrigated farms in the region. H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Willwood Formation
The Willwood Formation is a sedimentary sequence deposited during the late Paleocene to early Eocene, or Clarkforkian, Wasatchian and Bridgerian in the NALMA classification.Willwood Formation at .orgNeasham & Vondra, 1972 Description It consists of fine grained clastic rocks ( and ) interbedded with medium grained clastic rocks ( |
Rhyolite
Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture (geology), texture, but may be porphyritic, containing larger mineral crystals (phenocrysts) in an otherwise fine-grained matrix (geology), groundmass. The mineral assemblage is predominantly quartz, sanidine, and plagioclase. It is the extrusive equivalent of granite. Its high silica content makes rhyolitic magma extremely viscosity, viscous. This favors explosive eruptions over effusive eruptions, so this type of magma is more often erupted as pyroclastic rock than as lava flows. Rhyolitic ash-flow tuffs are among the most voluminous of continental igneous rock formations. Rhyolitic tuff has been used extensively for construction. Obsidian, which is rhyolitic volcanic glass, has been used for tools from prehistoric times to the present day because it can be shaped to an extremely sharp edge. Rhyolitic pumice finds use as an abrasive, in concrete, and as a soil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
