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Vitrinite
Vitrinite is one of the primary components of coals and most sedimentary kerogens. Vitrinite is a type of maceral, where "macerals" are organic components of coal analogous to the "minerals" of rocks. Vitrinite has a shiny appearance resembling glass (vitreous). It is derived from the cell-wall material or woody tissue of the plants from which coal was formed. Chemically, it is composed of polymers, cellulose and lignin. Vitrinite Reflectance (Ro%) : Vitrinite reflectance (Ro%) is a very important geochemical parameter used to assess and evaluate the thermal maturity of sedimentary rocks, particularly those rich in organic matter. It is measure of the reflectivity of vitrinite—a type of maceral (organic component of coal and sedimentary rock)—when viewed under a microscope using oil immersion and reflected light.It is expressed as a percentage (Ro%), vitrinite reflectance increases with greater burial depth and thermal exposure, making it a reliable indicator of the maximum te ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other Chemical element, elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is a type of fossil fuel, formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during the late Carboniferous (Pennsylvanian (geology), Pennsylvanian) and Permian times. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution. With the invention of the steam engine, coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its Electricity generation, electricity. Some iron and steel-maki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maceral
A maceral is a component, organic in origin, of coal or oil shale. The term 'maceral' in reference to coal is analogous to the use of the term 'mineral' in reference to igneous or metamorphic rocks. Examples of macerals are inertinite, vitrinite, and liptinite. Inertinite Inertinite is considered to be the equivalent of charcoal and degraded plant material. It is highly oxidised in nature and may be said to be burnt. A large portion of South Africa's coal reserves consist of inertinite. Vitrinite Vitrinite is shiny, glass-like material that is considered to be composed of cellular plant material such as roots, bark, plant stems and tree trunks. Vitrinite macerals when observed under the microscope show a boxlike, cellular structure, often with oblong voids and cavities which are likely the remains of plant stems. This has a high calorific value (24 - 28 MJ/kg) and a large proportion of volatile matter (24 - 30%). It often occurs interbanded or interlaminated with inertini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kerogens
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 1016 tons of carbon. This makes it the most abundant source of organic compounds on earth, exceeding the total organic content of living matter 10,000-fold. The type of kerogen present in a particular rock formation depends on the type of organic material that was originally present. Kerogen can be classified by these origins: lacustrine (e.g., algal), marine (e.g., planktonic), and terrestrial (e.g., pollen and spores). The type of kerogen depends also on the degree of heat and pressure it has been subjected to, and the length of time the geological processes ran. The result is that a complex mixture of organic compounds resides in sedimentary rocks, serving as the precursor for the formation of hydro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metamorphism
Metamorphism is the transformation of existing Rock (geology), rock (the protolith) to rock with a different mineral composition or Texture (geology), texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chemically active fluids, but the rock remains mostly solid during the transformation. Metamorphism is distinct from weathering or diagenesis, which are changes that take place at or just beneath Earth's surface. Various forms of metamorphism exist, including Regional metamorphism, regional, Contact metamorphism, contact, Hydrothermal metamorphism, hydrothermal, Shock metamorphism, shock, and Dynamic metamorphism, dynamic metamorphism. These differ in the characteristic temperatures, pressures, and rate at which they take place and in the extent to which reactive fluids are involved. Metamorphism occurring at increasing pressure and temperature conditions is known as ''prograde metamorphism'', while decreasin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal History Modelling
Thermal history modelling is an exercise undertaken during basin modelling to evaluate the temperature history of stratigraphic layers in a sedimentary basin. The thermal history of a basin is usually calibrated using thermal indicator data, including vitrinite reflectance and fission tracks in the minerals apatite and zircon. The temperatures undergone by rocks in a sedimentary basin are crucial when attempting to evaluate the quantity, nature and volume of hydrocarbons (fossil fuels) produced by diagenesis of kerogens (a group of chemicals formed from the decay of organic matter). Fourier's law provides a simplified one-dimensional description of the variation in heat flow ''Q'' as a function of thermal conductivity ''k'' and thermal gradient ''dT''/''dz'': :Q=-k\frac (The minus sign indicates that heat flows in the opposite direction to increasing depth, that is, towards the Earth's surface.) If the assumptions used to justify this simplified approximation (i.e. steady-state ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University College London
University College London (Trade name, branded as UCL) is a Public university, public research university in London, England. It is a Member institutions of the University of London, member institution of the Federal university, federal University of London, and is the second-largest list of universities in the United Kingdom by enrolment, university in the United Kingdom by total enrolment and the largest by postgraduate enrolment. Established in 1826 as London University (though without university degree-awarding powers) by founders who were inspired by the radical ideas of Jeremy Bentham, UCL was the first university institution to be established in London, and the first in England to be entirely secular and to admit students regardless of their religion. It was also, in 1878, among the first university colleges to admit women alongside men, two years after University College, Bristol, had done so. Intended by its founders to be Third-oldest university in England debate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geology
Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology. It is integrated with Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface and the processes that have shaped that structure. Geologists study the mineralogical composition of rocks in order to get insight into their history of formation. Geology determines the relative ages of rocks found at a given location; geochemistry (a branch of geology) determines their absolute ages. By combining various petrological, crystallographic, and paleontological tools, geologists are able to chronicle the geological history of the Earth as a whole. One aspect is to demonstrate the age of the Earth. Geology provides evidence for plate tectonics, the ev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fossil Fuel
A fossil fuel is a flammable carbon compound- or hydrocarbon-containing material formed naturally in the Earth's crust from the buried remains of prehistoric organisms (animals, plants or microplanktons), a process that occurs within geological formations. Reservoirs of such compound mixtures, such as coal, petroleum and natural gas, can be extracted and burnt as fuel for human consumption to provide energy for direct use (such as for cooking, heating or lighting), to power heat engines (such as steam or internal combustion engines) that can propel vehicles, or to generate electricity via steam turbine generators. Some fossil fuels are further refined into derivatives such as kerosene, gasoline and diesel, or converted into petrochemicals such as polyolefins ( plastics), aromatics and synthetic resins. The origin of fossil fuels is the anaerobic decomposition of buried dead organisms. The conversion from these organic materials to high-carbon fossil fuels is ty ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exinite
In coal geology, liptinite is the finely-ground and macerated remains found in coal deposits. It replaced the term exinite as one of the four categories of kerogen. Liptinites were originally formed by spores, pollen, dinoflagellate cysts, leaf cuticles, and plant resins and waxes.Taylor et al., 1998. Organic Petrography. Gebrüder Borntraeger, Berlin. pp. 176 M.C. Stopes introduced the term ''exinite'' in 1935 to describe the microscopic constituent of coal, rich in volatiles and relatively rich in hydrogen, that is represented by the exines of spores. C.A. Seyler in 1932, however, used the term with its present meaning, designating the following group of macerals: sporinite, cutinite, alginite (telalginite and lamalginite), resinite. Macerals A maceral is a component, organic in origin, of coal or oil shale. The term 'maceral' in reference to coal is analogous to the use of the term 'mineral' in reference to igneous or metamorphic rock, metamorphic rocks. Examples of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Basin Modelling
Basin modelling is the term broadly applied to a group of geological disciplines that can be used to analyse the formation and evolution of sedimentary basins, often but not exclusively to aid evaluation of potential hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and Hydrophobe, hydrophobic; their odor is usually fain ... reserves. At its most basic, a basin modelling exercise must assess: # The burial history of the basin (see back-stripping). # The thermal history of the basin (see thermal history modelling). # The maturity history of the source rocks. # The expulsion, migration and trapping of hydrocarbons. By doing so, valuable inferences can be made about such matters as hydrocarbon generation and timing, maturity of potential source rocks and migration paths of expelled hydrocarbons. Basin modelling software Softwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
