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33-640: The Yanshanian movement were first recognized by Weng WH (1927,1929) in the Yanshan area of China (116°-119.5°N, 40°-42°E). Since then, the Yanshanian has been used as a local term in China for tectonic events which occurred mainly during the Jurassic Period . Later, Ding WJ (1929), Huang JQ (1945,1960) and Zhao ZF (1959) extended the term to cover tectonic events which occurred throughout China during

66-427: A detachment layer is present. Thrust tectonics is associated with the shortening and thickening of the crust, or the lithosphere. This type of tectonics is found at zones of continental collision , at restraining bends in strike-slip faults, and at the oceanward part of passive margin sequences where a detachment layer is present. Strike-slip tectonics is associated with the relative lateral movement of parts of

99-607: A regime's tectonic origin and development as well as the lithospheric mechanics. Migrating fluids originate from the sediments of the foreland basin and migrate in response to deformation. As a result, brine can migrate over great distances. Evidence of long-range migration includes: 1) correlation of petroleum to distant source rocks , 2) ore bodies deposited from metal-bearing brines, 3) anomalous thermal histories for shallow sediments, 4) regional potassium metasomatism and 5) epigenetic dolomite cements in ore bodies and deep aquifers. Fluids carrying heat, minerals, and petroleum, have

132-510: A thorough definition of the foreland basin system. Foreland basin systems comprise three characteristic properties: The wedge-top sits on top of the moving thrust sheets and contains all the sediments charging from the active tectonic thrust wedge. This is where piggyback basins form. The foredeep is the thickest sedimentary zone and thickens toward the orogen. Sediments are deposited via distal fluvial, lacustrine, deltaic, and marine depositional systems. The forebulge and backbulge are

165-454: A vast impact on the tectonic regime within the foreland basin. Before deformation, sediment layers are porous and full of fluids, such as water and hydrated minerals. Once these sediments are buried and compacted, the pores become smaller and some of the fluids, about ⁠ 1 / 3 ⁠ , leave the pores. This fluid has to go somewhere. Within the foreland basin, these fluids potentially can heat and mineralize materials, as well as mix with

198-538: Is a stub . You can help Misplaced Pages by expanding it . Tectonic Tectonics (from Latin tectonicus ; from Ancient Greek τεκτονικός ( tektonikós )  'pertaining to building ') are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of planetary tectonics extends the concept to other planets and moons. These processes include those of mountain-building ,

231-410: Is a factor of temperature and time and occurs at shallower depths due to past heat redistribution of migrating brines. Vitrinite reflectance, which typically demonstrates an exponential evolution of organic matter as a function of time, is the best organic indicator for thermal maturation. Studies have shown that present day thermal measurements of heat flow and geothermal gradients closely correspond to

264-426: Is a function of topographic relief. For the loading model, the lithosphere is initially stiff, with the basin broad and shallow. Relaxation of the lithosphere allows subsidence near the thrust, narrowing of basin, forebulge toward thrust. During times of thrusting, the lithosphere is stiff and the forebulge broadens. The timing of the thrust deformation is opposite that of the relaxing of the lithosphere. The bending of

297-413: Is associated with the stretching and thinning of the crust or the lithosphere . This type of tectonics is found at divergent plate boundaries, in continental rifts , during and after a period of continental collision caused by the lateral spreading of the thickened crust formed, at releasing bends in strike-slip faults , in back-arc basins , and on the continental end of passive margin sequences where

330-421: Is formed in the process of sea-floor spreading ; transform , where plates slide past each other, and convergent , where plates converge and lithosphere is "consumed" by the process of subduction . Convergent and transform boundaries are responsible for most of the world's major ( M w > 7) earthquakes . Convergent and divergent boundaries are also the site of most of the world's volcanoes , such as around

363-401: Is the study of the motions and deformations of the Earth's crust ( geological and geomorphological processes) that are current or recent in geological time . The term may also refer to the motions and deformations themselves. The corresponding time frame is referred to as the neotectonic period . Accordingly, the preceding time is referred to as palaeotectonic period . Tectonophysics is

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396-586: The foreland to a collisional belt. In plate tectonics, the outermost part of the Earth known as the lithosphere (the crust and uppermost mantle ) act as a single mechanical layer. The lithosphere is divided into separate "plates" that move relative to each other on the underlying, relatively weak asthenosphere in a process ultimately driven by the continuous loss of heat from the Earth's interior. There are three main types of plate boundaries: divergent , where plates move apart from each other and new lithosphere

429-470: The seismic hazard of an area. Impact tectonics is the study of modification of the lithosphere through high velocity impact cratering events. Techniques used in the analysis of tectonics on Earth have also been applied to the study of the planets and their moons, especially icy moons . Foreland basin Foreland basins can be divided into two categories: DeCelles & Giles (1996) provide

462-747: The Jurassic and Cretaceous tectonic periods. However, it was soon realized that tectonic and magmatic events in the Jurassic and Cretaceous were very different. In the Jurassic there are NNE-NE trending folds and thrusts related to transpressional tectonics, and WNW trending normal faults with some strike-slip movement and widespread calc-alkaline magmatism , while the Cretaceous is characterized predominantly by extensional tectonics with NE-NNE trending normal faults , WNW trending folds and thrusts and highly alkaline acid magmatism located along faults, or at fault intersection. This tectonics article

495-466: The Pacific Ring of Fire . Most of the deformation in the lithosphere is related to the interaction between plates at or near plate boundaries. The latest studies, based on the integration of available geological data, and satellite imagery and Gravimetric and magnetic anomaly datasets have shown that the crust of the Earth is dissected by thousands of different types of tectonic elements which define

528-402: The active deformation zone with which it is connected. Today GPS measurements provide the rate at which one plate is moving relative to another. It is also important to consider that present day kinematics are unlikely to be the same as when deformation began. Thus, it is crucial to consider non-GPS models to determine the long-term evolution of continental collisions and in how it helped develop

561-399: The adjacent foreland basins. Comparing both modern GPS (Sella et al. 2002) and non-GPS models allows deformation rates to be calculated. Comparing these numbers to the geologic regime helps constrain the number of probable models as well as which model is more geologically accurate within a specific region. Seismicity determines where active zones of seismic activity occur as well as measure

594-436: The basin becomes completely filled. At this point, the basin enters the overfilled stage and deposition of terrestrial clastic sediments occurs. These are known as molasse . Sediment fill within the foredeep acts as an additional load on the continental lithosphere. Although the degree to which the lithosphere relaxes over time is still controversial, most workers accept an elastic or visco-elastic rheology to describe

627-419: The crust or the lithosphere. This type of tectonics is found along oceanic and continental transform faults which connect offset segments of mid-ocean ridges . Strike-slip tectonics also occurs at lateral offsets in extensional and thrust fault systems. In areas involved with plate collisions strike-slip deformation occurs in the over-riding plate in zones of oblique collision and accommodates deformation in

660-670: The growth and behavior of the strong, old cores of continents known as cratons , and the ways in which the relatively rigid plates that constitute the Earth's outer shell interact with each other. Principles of tectonics also provide a framework for understanding the earthquake and volcanic belts that directly affect much of the global population. Tectonic studies are important as guides for economic geologists searching for fossil fuels and ore deposits of metallic and nonmetallic resources. An understanding of tectonic principles can help geomorphologists to explain erosion patterns and other Earth-surface features. Extensional tectonics

693-497: The lithosphere under the orogenic load controls the drainage pattern of the foreland basin. The flexural tilting of the basin and the sediment supply from the orogen. Strength envelopes indicate that the rheological structure of the lithosphere underneath the foreland and the orogen are very different. The foreland basin typically shows a thermal and rheological structure similar to a rifted continental margin with three brittle layers above three ductile layers. The temperature underneath

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726-458: The lithosphere. Thus, the thrust belt is mobile and the foreland basin system becomes deformed over time. Syntectonic unconformities demonstrate simultaneous subsidence and tectonic activity. Foreland basins are filled with sediments which erode from the adjacent mountain belt. In the early stages, the foreland basin is said to be underfilled . During this stage, deep water and commonly marine sediments, known as flysch , are deposited. Eventually,

759-425: The lithospheric deformation of the foreland basin. Allen & Allen (2005) describe a moving load system, one in which the deflection moves as a wave through the foreland plate before the load system. The deflection shape is commonly described as an asymmetrical low close to the load along the foreland and a broader uplifted deflection along the forebulge. The transport rate or flux of erosion, as well as sedimentation,

792-457: The local hydrostatic head. Orogen topography is the major driving force of fluid migration. The heat from the lower crust moves via conduction and groundwater advection . Local hydrothermal areas occur when deep fluid flow moves very quickly. This can also explain very high temperatures at shallow depths. Other minor constraints include tectonic compression, thrusting, and sediment compaction. These are considered minor because they are limited by

825-411: The orogen is much higher and thus greatly weakens the lithosphere. According to Zhou et al. (2003), "under compressional stress the lithosphere beneath the mountain range becomes ductile almost entirely, except a thin (about 6 km in the center) brittle layer near the surface and perhaps a thin brittle layer in the uppermost mantle." This lithospheric weakening underneath the orogenic belt may in part cause

858-404: The passive margin stage with orogenic loading of previously stretched continental margin during the early stages of convergence. Second, the "early convergence stage defined by deep water conditions", and lastly a "later convergent stage during which a subaerial wedge is flanked with terrestrial or shallow marine foreland basins". The temperature underneath the orogen is much higher and weakens

891-498: The regional lithospheric flexure behavior. Foreland basins are considered to be hypothermal basins (cooler than normal), with low geothermal gradient and heat flow . Heat flow values average between 1 and 2 HFU (40–90 mWm . Rapid subsidence may be responsible for these low values. Over time sedimentary layers become buried and lose porosity. This can be due to sediment compaction or the physical or chemical changes, such as pressure or cementation . Thermal maturation of sediments

924-401: The slow rates of tectonic deformation, lithology and depositional rates, on the order of 0–10 cm yr , but more likely closer to 1 or less than 1 cm yr . Overpressured zones might allow for faster migration, when 1 kilometer or more of shaley sediments accumulate per 1 million years. Bethke & Marshak (1990) state that "groundwater that recharges at high elevation migrates through

957-576: The study of the physical processes associated with deformation of the crust and mantle from the scale of individual mineral grains up to that of tectonic plates. Seismotectonics is the study of the relationship between earthquakes, active tectonics, and individual faults in a region. It seeks to understand which faults are responsible for seismic activity in an area by analysing a combination of regional tectonics, recent instrumentally recorded events, accounts of historical earthquakes, and geomorphological evidence. This information can then be used to quantify

990-403: The subdivision into numerous smaller microplates which have amalgamated into the larger Plates. Salt tectonics is concerned with the structural geometries and deformation processes associated with the presence of significant thicknesses of rock salt within a sequence of rocks. This is due both to the low density of salt, which does not increase with burial, and its low strength. Neotectonics

1023-441: The subsurface in response to its high potential energy toward areas where the water table is lower." Bethke & Marshak (1990) explain that petroleum migrates not only in response to the hydrodynamic forces that drive groundwater flow, but to the buoyancy and capillary effects of the petroleum moving through microscopic pores. Migration patterns flow away from the orogenic belt and into the cratonic interior. Frequently, natural gas

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1056-429: The thinnest and most distal zones and are not always present. When present, they are defined by regional unconformities as well as aeolian and shallow-marine deposits. Sedimentation is most rapid near the moving thrust sheet. Sediment transport within the foredeep is generally parallel to the strike of the thrust fault and basin axis. The motion of the adjacent plates of the foreland basin can be determined by studying

1089-449: The total fault displacements and the timing of the onset of deformation. Foreland basins form because as the mountain belt grows, it exerts a significant mass on the Earth's crust, which causes it to bend, or flex, downwards. This occurs so that the weight of the mountain belt can be compensated by isostasy at the upflex of the forebulge. The plate tectonic evolution of a peripheral foreland basin involves three general stages. First,

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