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Metamorphic rocks are formed by subjecting any rock type—sedimentary rock, igneous rock or another older metamorphic rock—to different temperature and pressure conditions than those in which the original rock was formed. This process is called metamorphism, meaning to "change in form". The result is a profound change in physical properties ...
Organic-rich sedimentary rocks may act as source rocks which generate hydrocarbons that accumulate in other sedimentary "reservoir" rocks [2] (see oil sands and petroleum geology). Potential source rocks are any type of sedimentary rock that the ability to dispel available carbon from within it (limestone is a classic example of a source rock ...
Sedimentary organic matter includes the organic carbon component of sediments and sedimentary rocks. The organic matter is usually a component of sedimentary material even if it is present in low abundance (usually lower than 1%). Petroleum (or oil) and natural gas are particular examples of sedimentary organic matter.
The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes.
The uppermost part of the regolith, which typically contains significant organic matter, is more conventionally referred to as soil. [15] The presence of regolith is one of the important factors for most life, since few plants can grow on or within solid rock and animals would be unable to burrow or build shelter without loose material. [16]
Organic matter is mineralized, liberating gaseous carbon dioxide (CO 2) in the porewater, which, depending on the conditions, can diffuse into the water column. The various processes of mineralization in this phase are nitrification and denitrification , manganese oxide reduction, iron hydroxide reduction, sulfate reduction , and fermentation .
Kerogen is solid, insoluble organic matter in sedimentary rocks. It consists of a variety of organic materials, including dead plants, algae, and other microorganisms, that have been compressed and heated by geological processes. All the kerogen on earth is estimated to contain 10 16 tons of carbon. This makes it the most abundant source of ...
The organic matter in oil shales forms a complex macromolecular structure which is insoluble in common organic solvents. [ 1 ] [ 10 ] It is mixed with varied amounts of mineral matter. For commercial grades of oil shale, the ratio of organic matter to mineral matter is about 0.75:5 to 1.5:5.