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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 or both of the surfaces.
It represents the foot of the cliff preserved at and below the level of water table. If there is a tectonic uplift of the coast, these abrasion platforms can be raised to form coastal terraces, from which the amount of uplift can be calculated from their elevation relative to the sea level, taking into account any eustatic sea level changes. On ...
Abrasion occurs in natural environments such as beaches, sand dunes, river or stream beds by the action of current flow, wave impact, glacial action, wind, gravitational creep and other erosive agents. Recent studies have demonstrated that aeolian processes are more efficient in the rounding of sedimentary grains.
A continued supply of abrading fragments is required to uphold a similar level of abrasion. The fragments must be harder than the bedrock. Quartz fragments will abrade shale but shale fragments will not abrade a quartz rich bedrock. A constant flow of meltwater between the basal surface and the bedrock speeds abrasion.
A raised beach, coastal terrace, [1] or perched coastline is a relatively flat, horizontal or gently inclined surface of marine origin, [2] mostly an old abrasion platform which has been lifted out of the sphere of wave activity (sometimes called "tread"). Thus, it lies above or under the current sea level, depending on the time of its formation.
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 ...
A marine terrace represents the former shoreline of a sea or ocean. It can be formed by marine abrasion or erosion of materials comprising the shoreline (marine-cut terraces or wave-cut platforms); the accumulations of sediments in the shallow-water to slightly emerged coastal environments (marine-built terraces or raised beach); or the bioconstruction by coral reefs and accumulation of reef ...
Remnants of former floodplains stand as terraces above the river's modern level. Downcutting , also called erosional downcutting , downward erosion or vertical erosion , is a geological process by hydraulic action that deepens the channel of a stream or valley by removing material from the stream's bed or the valley's floor.