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Foredeep
A foreland basin is a structural basin that develops adjacent and parallel to a mountain belt. Foreland basins form because the immense mass created by crustal thickening associated with the evolution of a mountain belt causes the lithosphere to bend, by a process known as lithospheric flexure. The width and depth of the foreland basin is determined by the flexural rigidity of the underlying lithosphere, and the characteristics of the mountain belt. The foreland basin receives sediment that is eroded off the adjacent mountain belt, filling with thick sedimentary successions that thin away from the mountain belt. Foreland basins represent an endmember basin type, the other being rift basins. Space for sediments (accommodation space) is provided by loading and downflexure to form foreland basins, in contrast to rift basins, where accommodation space is generated by lithospheric extension. Types of foreland basin Foreland basins can be divided into two categories: * Periphe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Piggyback Basin
A piggyback basin (also piggy-back, thrust-sheet-top, detached, or satellite basin) is a minor sedimentary basin developed on top of a moving thrust sheet as part of a foreland basin system. Piggyback basins form in the wedge-top depositional zone of a foreland basin system as new thrusts in the foreland cut up through the existing footwall containing the eroded wedge-top basins in the old thrust sheet. The basin is separated from the foredeep by an anticline or syndepositional growth structures. The piggyback basin is named after its tendency to be carried passively toward the hinterland with the old thrust sheet in response to the compressive forces of the new thrust sheet. Sedimentary fill for the basin come from the hanging wall ramp of the older thrust sheet, from the foreland orogeny or from the sides of the basin. Drainage into the basin may come from highs associated with the thrust sheets or the basin may be filled from longitudinal flows across the basin. The Po Basin of I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Forebulge
In geology, a forebulge is a flexural bulge in front as a result of a load on the lithosphere, often caused by tectonic interactions and glaciations. An example of forebulge can be seen in the Himalayan foreland basin, a result of the Indian-Eurasian (continent-continent) plate collision, in which the Indian plate subducted and the Eurasian plate created a large load on the lithosphere, leading to the Himalayas and the Ganges foreland basin. Background Forebulge is most commonly found with continent-continent convergent collisions, in which the formation of mountain ranges as the plates collide places a large load on the lithosphere below. The lithosphere flexes in response to the load on the mantle, causing depression and subsidence ( fordeep) followed by the forebulging in the front. The forebulge area is lifted by a height that is 4% of the depression height caused by the load. It takes roughly 10,000 to 20,000 years for forebulge to fully develop when the mantle flexure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molasse Basin
The Molasse basin (or North Alpine foreland basin) is a foreland basin north of the Alps which formed during the Oligocene and Miocene epochs. The basin formed as a result of the flexure of the European plate under the weight of the orogenic wedge of the Alps that was forming to the south. In geology, the name "molasse basin" is sometimes also used in a general sense for a synorogenic (formed contemporaneously with the orogen) foreland basin of the type north of the Alps. The basin is the type locality of molasse, a sedimentary sequence of conglomerates and sandstones, material that was removed from the developing mountain chain by erosion and denudation, that is typical for foreland basins. Geographic location The Molasse basin stretches over 1000 kilometers along the long axis of the Alps, in France, Switzerland, Germany and Austria. The west end is at Lake Geneva, where the basin's outcrop is just 20 km wide. Further to the northeast the basin becomes wider. It forms t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molasse
__NOTOC__ The term "molasse" () refers to sandstones, shales and conglomerates that form as terrestrial or shallow marine deposits in front of rising mountain chains. The molasse deposits accumulate in a foreland basin, especially on top of flysch-like deposits, for example, those that left from the rising Alps, or erosion in the Himalaya. These deposits are typically the non-marine alluvial and fluvial sediments of lowlands, as compared to deep-water flysch sediments. Sedimentation stops when the orogeny stops, or when the mountains have eroded flat. Stanley, Steven M., ''Earth System History'', New York: W.H. Freeman and Company, 1999, p.243 The molasse can sometimes completely fill a foreland basin, creating a nearly flat depositional surface, that nonetheless remains a structural syncline. Molasse can be very thick near the mountain front, but usually thins out towards the interior of a craton; such massive, convex Convex or convexity may refer to: Science and technolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subaerial
In natural science, subaerial (literally "under the air"), has been used since 1833,Subaerial in the Merriam-Webster dictionary. notably in and , to describe features and events occurring or formed on or near the 's land surface. They are thus exposed to Earth's atmosphere. This may be contrasted with '' subaqueous'' events or features located below a water surface, '' [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flysch
Flysch () is a sequence of sedimentary rock layers that progress from deep-water and turbidity flow deposits to shallow-water shales and sandstones. It is deposited when a deep basin forms rapidly on the continental side of a mountain building episode. Examples are found near the North American Cordillera, the Alps, the Pyrenees and the Carpathians. Sedimentological properties Flysch consists of repeated sedimentary cycles with upwards fining of the sediments. There are sometimes coarse conglomerates or breccias at the bottom of each cycle, which gradually evolve upwards into sandstone and shale/mudstone. Flysch typically consists of a sequence of shales rhythmically interbedded with thin, hard, graywacke-like sandstones. Typically the shales do not contain many fossils, while the coarser sandstones often have fractions of micas and glauconite. Tectonics In a continental collision, a subducting tectonic plate pushes on the plate above it, making the rock fold, often to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clastic
Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks by physical weathering.Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-5 Geologists use the term clastic to refer to sedimentary rocks and particles in sediment transport, whether in suspension or as bed load, and in sediment deposits. Sedimentary clastic rocks Clastic sedimentary rocks are rocks composed predominantly of broken pieces or ''clasts'' of older weathered and eroded rocks. Clastic sediments or sedimentary rocks are classified based on grain size, clast and cementing material (matrix) composition, and texture. The classification factors are often useful in determining a sample's environment of deposition. An example of clastic environment would be a river system in which the full range of grains being transpor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscoelastic Lithospheric Flexure
In materials science and continuum mechanics, viscoelasticity is the property of materials that exhibit both viscous and elastic characteristics when undergoing deformation. Viscous materials, like water, resist shear flow and strain linearly with time when a stress is applied. Elastic materials strain when stretched and immediately return to their original state once the stress is removed. Viscoelastic materials have elements of both of these properties and, as such, exhibit time-dependent strain. Whereas elasticity is usually the result of bond stretching along crystallographic planes in an ordered solid, viscosity is the result of the diffusion of atoms or molecules inside an amorphous material.Meyers and Chawla (1999): "Mechanical Behavior of Materials", 98-103. Background In the nineteenth century, physicists such as Maxwell, Boltzmann, and Kelvin researched and experimented with creep and recovery of glasses, metals, and rubbers. Viscoelasticity was further examined i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isostasy
Isostasy (Greek ''ísos'' "equal", ''stásis'' "standstill") or isostatic equilibrium is the state of gravitational equilibrium between Earth's crust (or lithosphere) and mantle such that the crust "floats" at an elevation that depends on its thickness and density. This concept is invoked to explain how different topographic heights can exist at Earth's surface. Although originally defined in terms of continental crust and mantle, it has subsequently been interpreted in terms of lithosphere and asthenosphere, particularly with respect to oceanic island volcanoes, such as the Hawaiian Islands. Although Earth is a dynamic system that responds to loads in many different ways, isostasy describes the important limiting case in which crust and mantle are in static equilibrium. Certain areas (such as the Himalayas and other convergent margins) are not in isostatic equilibrium and are not well described by isostatic models. The general term 'isostasy' was coined in 1882 by the Am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rheology
Rheology (; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an applied force. Rheology is a branch of physics, and it is the science that deals with the deformation and flow of materials, both solids and liquids.W. R. Schowalter (1978) Mechanics of Non-Newtonian Fluids Pergamon The term '' rheology'' was coined by Eugene C. Bingham, a professor at Lafayette College, in 1920, from a suggestion by a colleague, Markus Reiner.The Deborah Number The term was inspired by the of |
Geothermal Gradient
Geothermal gradient is the rate of temperature change with respect to increasing depth in Earth's interior. As a general rule, the crust temperature rises with depth due to the heat flow from the much hotter mantle; away from tectonic plate boundaries, temperature rises in about 25–30 °C/km (72–87 °F/mi) of depth near the surface in most of the world. However, in some cases the temperature may drop with increasing depth, especially near the surface, a phenomenon known as ''inverse'' or ''negative'' geothermal gradient. The effects of weather, sun, and season only reach a depth of approximately 10-20 metres. Strictly speaking, ''geo''-thermal necessarily refers to Earth but the concept may be applied to other planets. In SI units, the geothermal gradient is expressed as °C/km, K/km, or mK/m. These are all equivalent. Earth's internal heat comes from a combination of residual heat from planetary accretion, heat produced through radioactive decay, latent hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
