how are biogenous sediments formed?
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Biogenous sediments are formed from the remnants of organisms that refused to be dissolved. ... In deeper waters, shells of plankton and other microscopic organisms form these kinds of sediments. Hydrogenous sediments are sediments solidified out of ocean water. As such, chemical reactions create these kinds of sediments.
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Sedimentary rocks can be subdivided into four groups based on the processes responsible for their formation: clastic sedimentary rocks, biochemical (biogenic) sedimentary rocks, chemical sedimentary rocks, and a fourth category for "other" sedimentary rocks formed by impacts, volcanism, and other minor processes.
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Clastic sedimentary rocks are made of sediments. The sediments differ in size. Chemical sedimentary rocks are made of minerals that precipitate from saline water. Organic sedimentary rocks are made from the bodies of organisms.
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The oldest layers are on the bottom, and the youngest layers are on the top. Because sediments sometimes include once-living organisms, sedimentary rock often contains a lot of fossils. Fossils are once-living organisms that have been turned into rock, in which the shape or form of the organism can still be seen.
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A coal seam (layer) is formed by the alteration of dead plant material. Initially, this material accumulates as peat on the land surface. As the peat becomes buried beneath younger sediments the temperature increases with increasing depth of burial.
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Layered rocks form when particles settle from water or air. Steno's Law of Original Horizontality states that most sediments, when originally formed, were laid down horizontally. ... Rock layers are also called strata (the plural form of the Latin word stratum), and stratigraphy is the science of strata.
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Detrital sedimentary rocks form from detritus, the rock and mineral fragments that are transported by gravity, water, ice, or wind. Detrital sediments are classified by grain size. Detritus is classified by its grain size.
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2) Biogenic (biochemical) sedimentary rocks are those composed of materials formed by the activity of living organisms such as coal (compacted undecayed plant matter) and many limestones which are made up of the shells or other skeletal fragments from marine organisms.
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['Alluvial Soils: These are formed by the deposition of sediments by rivers. ... ', 'Black Soils: These soils are made up of volcanic rocks and lava-flow. ... ', 'Red Soils: These are derived from weathering of ancient metamorphic rocks of Deccan Plateau. ... ', 'Laterite Soils: ... ', 'Mountain Soils: ... ', 'Desert Soils:']
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Fossil formation begins when an organism or part of an organism falls into soft sediment, such as mud. The organism or part then gets quickly buried by more sediment. As more and more sediment collects on top, the layer with the organism or part becomes compacted.
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Sedimentary rocks are the product of 1) weathering of preexisting rocks, 2) transport of the weathering products, 3) deposition of the material, followed by 4) compaction, and 5) cementation of the sediment to form a rock. The latter two steps are called lithification.
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['Small pieces of rock are transported by a river.', 'Pieces of rock are deposited and layers of sediment build up.', 'Sediments are compacted and water is squeezed out. Crystals form, which cement the pieces of rock together.']
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Chemical sedimentary rocks, such as rock salt, iron ore, chert, flint, some dolomites, and some limestones, form when dissolved materials precipitate from solution. Organic sedimentary rocks such as coal, some dolomites, and some limestones, form from the accumulation of plant or animal debris.
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Sedimentary rocks are formed when small pieces of material are compressed and cemented together over time to form one whole rock. Detrital sedimentary rocks are formed from rock fragments, while chemical sedimentary rocks are formed from mineral crystals that form after dissolving out of water.
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When a stretch of coastline is formed from different types of rock, headlands and bays can form. ... When the softer rock is eroded inwards, the hard rock sticks out into the sea, forming a headland . Erosional features such as wave-cut platforms and cliffs can be found on headlands, since they are more open to the waves.
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Biogenic ooze, also called biogenic sediment, any pelagic sediment that contains more than 30 percent skeletal material. These sediments can be made up of either carbonate (or calcareous) ooze or siliceous ooze.
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Aeolian landforms are formed when wind moves sediment (see aeolian processes). Sediment particles move when they are lifted by upwards Bernoulli forces that exceed their downwards weight.