Sunday, December 21, 2014
Sands are a naturally occurring, unconsolidated sediment that consists of individual mineral grains with a grain size of 0.063 to 2 mm. They are coarser than silt so (grain size from 0.002 to 0.063 mm) and finer than gravel (grain size 2 to 63 mm). Sands are also one of non-cohesive soils - sand and gravel Lynnwood. The term "sands" is not dependent on the mineral composition. The vast majority of all Sandse, however, the majority of quartz grains.
Above all, this quartz sand is an important raw material for the construction industry as well as for the glass and semiconductor industry. The first sands the Earth's history originated from igneous and metamorphic rocks (eg. As granite or gneiss), which were divided by physical weathering into smaller blocks or caused by chemical weathering according prone rock components directly into individual mineral grains.
In addition, weathered limestone only in arid climate purely physical, otherwise preferably chemically, ie it is likely to be resolved rather than broken down into small fragments. In practice, however, one finds also slightly different class boundaries and names. The following list names other names: Very fine sand is in soil science traditionally than 0.125 mm - 0.250 mm excreted - classified according to DIN in fine sands.
Stepping volcanic islands of sands that have resulted from physical weathering of volcanic rocks. These include the greenish olivine and the dark basalt sands on the Hawaiian Islands. Basalt sands there, other than olivine or silica sands, due to microscopic size of mineral grains of basalt not to individual mineral grains, but from sands-grain-sized rock fragments.
Since the interior surface of a given volume of sand is greater than an equally large boulder weathering and erosion can start better for small grains, so that change particle size, particle shape and mineral composition of sands comparatively (as seen in geological time) quickly. The result of small grains even smaller by using smaller fragments are broken split along crystal boundaries or by collisions during transport.
Sharp sand is much more compact, both in sedimentation as well as in building materials, because tilting the grains. But they can be bad mix and weigh all the tools enormous. Blown sands are called the result of its purity, its small particle size and its good sorting through the wind very easily movable sands. If wide occurrence it occurs often in form of dunes in appearance.
By mechanical stress during transport, the shape of individual grains changes. In general, corners and edges are rounded and sandsed all the more so the longer the transit. However, this is not a linear process: The rounder and smaller the particles are, the more resistant they are against further changes. Investigations revealed that often a transport of thousands of kilometers is needed also to be rounded edged grains of sands medium size only moderate.
During transport along rivers this path lengths can be achieved only rarely, and the steady motions in surf zone of a coastal range in most cases is not sufficient to explain nowadays observable good rounding of many grains of sands, especially not when the sands mainly is made of durable quartz. This is explained by the fact that the vast majority of today occurring on earth sands weathering of sandstone comes and thus already has multiple erosion and sedimentation cycles behind: sands is deposited (sediment), covered by other sediments, thereby compacting. The sands grains are finally cemented together by a binder during diagenesis and a sandstone is formed.
Above all, this quartz sand is an important raw material for the construction industry as well as for the glass and semiconductor industry. The first sands the Earth's history originated from igneous and metamorphic rocks (eg. As granite or gneiss), which were divided by physical weathering into smaller blocks or caused by chemical weathering according prone rock components directly into individual mineral grains.
In addition, weathered limestone only in arid climate purely physical, otherwise preferably chemically, ie it is likely to be resolved rather than broken down into small fragments. In practice, however, one finds also slightly different class boundaries and names. The following list names other names: Very fine sand is in soil science traditionally than 0.125 mm - 0.250 mm excreted - classified according to DIN in fine sands.
Stepping volcanic islands of sands that have resulted from physical weathering of volcanic rocks. These include the greenish olivine and the dark basalt sands on the Hawaiian Islands. Basalt sands there, other than olivine or silica sands, due to microscopic size of mineral grains of basalt not to individual mineral grains, but from sands-grain-sized rock fragments.
Since the interior surface of a given volume of sand is greater than an equally large boulder weathering and erosion can start better for small grains, so that change particle size, particle shape and mineral composition of sands comparatively (as seen in geological time) quickly. The result of small grains even smaller by using smaller fragments are broken split along crystal boundaries or by collisions during transport.
Sharp sand is much more compact, both in sedimentation as well as in building materials, because tilting the grains. But they can be bad mix and weigh all the tools enormous. Blown sands are called the result of its purity, its small particle size and its good sorting through the wind very easily movable sands. If wide occurrence it occurs often in form of dunes in appearance.
By mechanical stress during transport, the shape of individual grains changes. In general, corners and edges are rounded and sandsed all the more so the longer the transit. However, this is not a linear process: The rounder and smaller the particles are, the more resistant they are against further changes. Investigations revealed that often a transport of thousands of kilometers is needed also to be rounded edged grains of sands medium size only moderate.
During transport along rivers this path lengths can be achieved only rarely, and the steady motions in surf zone of a coastal range in most cases is not sufficient to explain nowadays observable good rounding of many grains of sands, especially not when the sands mainly is made of durable quartz. This is explained by the fact that the vast majority of today occurring on earth sands weathering of sandstone comes and thus already has multiple erosion and sedimentation cycles behind: sands is deposited (sediment), covered by other sediments, thereby compacting. The sands grains are finally cemented together by a binder during diagenesis and a sandstone is formed.
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