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Clastic Sedimentary Rocks Essay

Sedimentary rocks are the rocks formed from compaction and cementation of fragments of pre-existing rocks called crystals. Exogenic processes such as weathering and erosion influence the formation of sedimentary rocks. This processes supply the materials (sediments), responsible for the formation of sedimentary rocks. Weathered materials are transported by the agents of denudation such as water, wind and ice; then are deposited in low altitude areas. The accumulated materials are compacted as results of increasing pressure, finally the material are cemented following the precipitation of silica, calcium carbonate or iron oxide between particles. Sedimentary rocks are formed in layers through the process called stratification, the layers formed are called strata. Usually the old rock strata underlie the young rock strata. The more you go deep, the older rock it becomes unless there is an abnormal. Fig 1: show strata of sedimentary rocks. Sedimentary rocks can be classified into two major categories namely, clastic and non -clastic sedimentary rocks. Clastic sedimentary rocks, according to Astrahler clastic sedimentary rocks are the rocks derived directly as particles broken from the parent rock source. Clastic sedimentary rocks are derived from any one of the rocks groups which are igneous rocks, sedimentary rocks or metamorphic rocks which gives a way wide range of parent materials. Clastic sedimentary rocks vary in size of particles from fine particles to courser particles, for instance from siltstone, sand stone to conglomerates which is formed by the compaction of large pebbles. Non- clastic sedimentary rocks , this the type of sedimentary rocks formed of newly created mineral matt... ... middle of paper ... ...trary to non-clastic sedimentary rocks which are less denser for instance dolomite and anhydrite. Non-clastic sedimentary rocks especially organically formed sedimentary rocks are responsible for forming crude oil and gas after millions of years where as Clastic sedimentary rocks form inorganic substances such as rocks including silt stone , sand stone , clay stone and conglomerate. However the two types of sedimentary rocks are all important to the nature. for instance clastic rocks provide building material like sand , Organically sedimentary formed rocks provided fuel such as coal, petroleum and natural gas .Also chemically formed sedimentary rocks provide rocks salt after precipitation . More over sedimentary rocks forms recreational resorts, like reefs and island .

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