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Corrasion
Corrasion is a geomorphological term for the process of mechanical erosion of the earth's surface caused when materials are transported across it by running water, waves, glaciers, wind or gravitational movement downslope. An example is the wearing away of rock on a river or seabed by the impact or grinding action of particles moving with the water. The resultant effect on the rock is called abrasion. Corrasion is different from corrosion which is due to chemical and solvent action of water on soluble or partly soluble rocks when they come in contact. Corrasion acts in two ways: # Lateral corrasion : the sideways erosion which widens the river. # Vertical corrasion: downward erosion which deepens the river valley. Thus corrasion is a form of erosion. See also * Attrition (erosion) *Bratschen *Coastal erosion * Helicoidal flow *Hydraulic action Hydraulic action, most generally, is the ability of moving water (flowing or waves) to dislodge and transport rock particles. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geomorphology
Geomorphology (from Ancient Greek: , ', "earth"; , ', "form"; and , ', "study") is the scientific study of the origin and evolution of topographic and bathymetric features created by physical, chemical or biological processes operating at or near Earth's surface. Geomorphologists seek to understand why landscapes look the way they do, to understand landform and terrain history and dynamics and to predict changes through a combination of field observations, physical experiments and numerical modeling. Geomorphologists work within disciplines such as physical geography, geology, geodesy, engineering geology, archaeology, climatology, and geotechnical engineering. This broad base of interests contributes to many research styles and interests within the field. Overview Earth's surface is modified by a combination of surface processes that shape landscapes, and geologic processes that cause tectonic uplift and subsidence, and shape the coastal geography. Surface processe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abrasion (geology)
Abrasion is a process of erosion which occurs when material being transported wears away at a surface over time. It is the process of friction caused by scuffing, scratching, wearing down, marring, and rubbing away of materials. The intensity of abrasion depends on the hardness, concentration, velocity and mass of the moving particles. Abrasion generally occurs in four ways: glaciation slowly grinds rocks picked up by ice against rock surfaces; solid objects transported in river channels make abrasive surface contact with the bed and walls; objects transported in waves breaking on coastlines; and by wind transporting sand or small stones against surface rocks. Abrasion, under its strictest definition, is commonly confused with attrition and sometimes hydraulic action however, the latter less commonly so. Both abrasion and attrition refers to the wearing down of an object. Abrasion occurs as a result of two surfaces rubbing against each other, resulting in the wearing down of one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corrosion
Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engineering is the field dedicated to controlling and preventing corrosion. In the most common use of the word, this means electrochemical oxidation of metal in reaction with an oxidant such as oxygen, hydrogen or hydroxide. Rusting, the formation of iron oxides, is a well-known example of electrochemical corrosion. This type of damage typically produces oxide(s) or salt(s) of the original metal and results in a distinctive orange colouration. Corrosion can also occur in materials other than metals, such as ceramics or polymers, although in this context, the term "degradation" is more common. Corrosion degrades the useful properties of materials and structures including strength, appearance and permeability to liquids and gases. Many str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Attrition (erosion)
Attrition is the process of erosion that occurs during rock collision and transportation. The transportation of sediment chips and smooths the surfaces of bedrock; this can be through water or wind. Rocks undergoing attrition erosion are often found on or near the bed of a stream. Attrition is also partially responsible for turning boulders into smaller rocks and eventually to sand. Attrition erosion allows past and present geologic changes to be understood as well as paleogeomorphic environments to be interpreted. Researchers use particle shapes (a result of attrition) to study erosion and environmental changes. Mechanism The amount of attrition is dependent on a number of factors: particle properties such as size, shape, surface, porosity, hardness, and cracks, as well as environmental properties such as time, velocity, pressure, shear, and temperature. Generally, particles are more affected by attrition farther downstream, as the rivers' velocity tends to be higher, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bratschen
''Bratschen'' are weathering products that occur as a result of frost and aeolian corrasion almost exclusively on the calc-schists of the Upper Slate Mantle (''Obere Schieferhülle'') in the High Tauern mountains of Austria. The term is German but is used untranslated in English sources. The calc-schist, which appears blue-gray when freshly broken, weathers to a yellow to brown colour and flakes off on the surface to form ''bratschen''. These form steep (up to 40°), rocky, almost unvegetated mountainsides with an odd and rough-textured surface, caused by wind erosion. ''Bratschen'' are found on the mountains such as the Fuscherkarkopf, the Großer Bärenkopf, the Kitzsteinhorn, the Schwerteck, or on the eponym An eponym is a person, a place, or a thing after whom or which someone or something is, or is believed to be, named. The adjectives which are derived from the word eponym include ''eponymous'' and ''eponymic''. Usage of the word The term ''epon ...ous Bratschenk� ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coastal Erosion
Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural. On non-rocky coasts, coastal erosion results in rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars. Over time the coast generally evens out. The softer areas fill up with sediment eroded from hard areas, and rock formations are eroded away. Also erosion comm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helicoidal Flow
Helicoidal flow is the cork-screw-like flow of water in a meander. It is one example of a secondary flow. Helicoidal flow is a contributing factor to the formation of slip-off slopes and river cliffs in a meandering section of the river. The helicoidal motion of the flow aids the processes of hydraulic action and corrasion on the outside of the meander, and sweeps sediment across the floor of the meander towards the inside of the meander, forming point bar deposits. See also *Laminar flow *Turbulent flow In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between t ... * Baer's law * Secondary flow in river bends References Bibliography Journal of Geophysical Research, Volume 107 (2002) Rivers {{Fluiddynamics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Action
Hydraulic action, most generally, is the ability of moving water (flowing or waves) to dislodge and transport rock particles. This includes a number of specific erosional processes, including abrasion, at facilitated erosion, such as ''static erosion'' where water leaches salts and floats off organic material from unconsolidated sediments, and from ''chemical erosion'' more often called chemical weathering. It is a mechanical process, in which the moving water current flows against the banks and bed of a river, thereby removing rock particles. A primary example of hydraulic action is a wave striking a cliff face which compresses the air in cracks of the rocks. This exerts pressure on the surrounding rock which can progressively crack, break, splinter and detach rock particles. This is followed by the decompression of the air as the wave retreats which can occur suddenly with explosive force which additionally weakens the rock. Cracks are gradually widened so each wave compresses ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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