"How Coal Was Formed" short message presented in this article will help you prepare for the lesson and expand your knowledge on this topic.
The message "How coal was formed"
Coal is an irreplaceable, exhaustible, solid mineral used by humans to generate heat in the process of burning it. It belongs to sedimentary rocks.
What is needed to form coal?
First, a lot of time. When peat is formed from plants at the bottom of swamps, chemical compounds arise: plants decay, partially dissolve or turn into methane, carbon dioxide.
Secondly, all kinds of fungi and bacteria. Thanks to them, the decomposition of plant tissue occurs. Peat begins to accumulate a persistent substance called carbon, which becomes more and more over time.
Thirdly, the lack of oxygen. If it accumulated in peat, then coal could not form and simply evaporated.
How is coal formed in nature?
Coal deposits were formed from a huge amount of plant matter. Ideal conditions are when all these plants have accumulated in one place and have not had time to completely decompose. Swamps are the best suited for this process: the water is poor in oxygen and therefore the vital activity of bacteria is suspended.
After the plant mass has accumulated in the swamps, it, without having time to completely rot, is compressed by soil deposits. This is how the source material of coal, peat, is formed. Layers of soil seal it in the ground without access to oxygen and water. Over time, peat turns into a layer of coal. This process is long - a significant part of the coal reserves was formed more than 300 million years ago.
And the longer the coal lies in the layers of the earth, the stronger the fossil is exposed to the action and pressure of deep heat. In swamps where peat accumulates, sand, clay and dissolved substances enter with water, which are deposited in coal. These impurities give interlayers in the mineral, dividing it into layers. When coal is cleaned, only ash remains from them.
There are several types of coal - bituminous coal, brown coal, lignite, boghead, anthracite. Today there are 3.6 thousand coal basins in the world, which occupy 15% of the earth's land. The United States holds the largest percentage of the world's fossil reserves (23%), followed by Russia (13%) and China third (11%).
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About coal
Coal is a solid, exhaustible, non-renewable mineral that a person uses to generate heat by burning it. According to the classification, it belongs to sedimentary rocks.
What it is?
Coal as a source of energy, people began to use in antiquity along with firewood. The “flammable stone” was found on the surface of the earth, later it was purposefully mined from under it.
Coal appeared on Earth about 300-350 million years ago, when tree-like ferns flourished on primeval swamps and the first gymnosperms began to appear. Huge trunks fell into the water, gradually forming thick layers of undecomposed organic mass. Wood with limited access to oxygen did not rot, but gradually sank deeper and deeper under its weight. Over time, due to the displacement of the layers of the earth's crust, these layers sank to a considerable depth, and there, under the influence of great pressure and elevated temperature, a qualitative change took place in wood into coal.
Types of coal
mined today different kinds coal.
Anthracite - the most hard varieties from great depths and having a maximum combustion temperature. Hard coal - many varieties mined in mines and open pit. It has the widest distribution in many areas of human activity. Brown coal - formed from the remains of peat, the youngest type of coal. It has the lowest combustion temperature.
All types of coal lie in layers and their locations are called coal basins.
Coal mining
At first, coal was simply collected at the places where the seam came to the surface. This could have happened as a result of the displacement of the layers of the earth's crust.
Often, after landslides in mountainous areas, such outcrops of the deposit were exposed, and people got the opportunity to get to pieces of “combustible stone”.
Later, when primitive technology appeared, coal began to be developed in an open way. Some coal mines plunged to a depth of more than 300 meters.
Today, thanks to the availability of sophisticated modern technology, people descend underground into mines more than a kilometer deep. From these horizons, the highest quality and valuable coal is mined.
Where is coal used?
All types of coal can be used to generate heat. When burned, it is released into more than you can get it from firewood or other solid fuels. The hottest grades of coal are used in metallurgy, where high temperatures are needed.
In addition, coal is a valuable raw material for the chemical industry. Many useful and useful substances are extracted from it.
Coal- solid fossil fuel plant origin, a type of fossil coal, intermediate between brown coal and anthracite. Coal is a dense sedimentary rock of black, sometimes cepo-black color, giving a black line on a porcelain plate. Organic matter contains 75-92% carbon, 2.5-5.7% hydrogen, 1.5-15% oxygen. The higher calorific value in terms of dry ashless state is 30.5-36.8 MJ/kg. Most hard coals are humoliths; sapropelites and humitosapropelites are present as lenses or small layers.
Coal is a product of deep decomposition of plant remains (tree ferns, horsetails and club mosses, as well as the first gymnosperms). Most coal deposits were formed in the Paleozoic, predominantly in the Carboniferous period, approximately 300-350 million years ago. The formation of coal is characteristic of almost all geological systems - from the Devonian to the Neogene (inclusive); they were widely used in the Carboniferous, Permian, and Jurassic.
Bituminous coals occur in the form of seams and lenticular deposits of various thicknesses (from fractions of meters to several tens and hundreds of meters) at different depths (from outcrops to 2,500 m and deeper). Coals are formed from the decomposition products of organic residues. higher plants that have undergone changes (metamorphism) under the pressure of the surrounding rocks of the earth's crust and relatively high temperatures.
Coal is characterized by a neutral composition of the organic mass. They do not react with weak alkalis either under normal conditions or under pressure. Their bitumens, in contrast to brown coals, are mainly represented by compounds of aromatic structure. Fatty acids and esters were not found in them, compounds with the structure of paraffins are of little importance. Hard coals are divided into shiny, semi-shiny, semi-matte, matte. Depending on the predominance of certain petrographic components, vitren, claren, dureno-claren, clarene-durene, durene and fuse coals are distinguished. Seams of coal can be composed of one of the indicated lithotypes, more often their alternation ( banded coals). As a rule, shiny varieties of coal are low-ash due to the insignificant content of mineral impurities.
Among the structures of the predominant substance of coals (coal-forming microcomponents), 4 types (thelinitic, post-thelinitic, precollinite and collinite) are distinguished, which are successive stages of a single process of decomposition of lignin-cellulosic tissues and reflect the general patterns of formation of coal-bearing formations. The main units of classification of hard coals are genetic groups established by the structure of the substance of coal-forming microcomponents, where, in addition to the 4 types mentioned, leuptinite coals are additionally included. Thus, 5 genetic groups have been identified. Each of them is divided into corresponding classes according to the type of substance of coal-forming microcomponents.
Under conditions of increasing pressure and temperature, when the coal-bearing stratum is immersed to a depth, a consistent transformation of the organic part of coal occurs - a change in its chemical composition, physical properties and intramolecular structure, defined by the term "regional coal metamorphism". At the final (highest) stage of metamorphism, bituminous coals are transformed into anthracites and graphites with a distinct crystal structure. Less common are transformations of the organic part of hard coals from exposure to the heat of igneous rocks that have intruded into coal-bearing strata or overlying (underlying) their deposits (thermal metamorphism), as well as directly into coal seams (contact metamorphism). An increase in the degree of metamorphism in the organic matter of hard coals is caused by a successive increase in the relative content of carbon and a decrease in the content of oxygen and hydrogen. The yield of volatile substances is consistently reduced (from 50 to 8% in terms of dry ash-free state); also change the heat of combustion, the ability to sinter into coke and physical properties coal.
The change in the physical properties of hard coals as a result of their metamorphism manifests itself according to a linear, dependent on the compaction of matter, or parabolic laws with inversion in coals of the middle stage of metamorphism, reflecting changes in the structure of organic matter. Luster, reflectivity of vitrinite, bulk density of coals and other properties change according to a linear law. Other important physical properties (porosity, density, caking, heat of combustion, elastic properties, etc.) change either distinctly according to a parabolic law, or according to a mixed one, when the change in properties occurs only when coal passes to the lean stage (microhardness, electrical conductivity, etc.) .
As an optical criterion for the degree of metamorphism of coals, the indicator of the reflectivity of vitrinite is used; this indicator is also used in petroleum geology to establish the stage of catagenic transformation of the sedimentary strata containing organic matter. The density of hard coals depends on the petrographic composition, the quantitative content and nature of mineral impurities and the degree of metamorphism. The highest density (1300-1500 kg / m 3) is characterized by the components of the fusinite group, the lowest (1280-1300 kg / m 3) - of the vitrinite group. The change in density with an increase in the degree of metamorphism occurs according to a parabolic law with inversion in the zone of transition to the fatty group; in low-ash varieties, it decreases from coal grade D to grade Zh on average from 1370 to 1280 kg/m 3 and then sequentially increases to coal grade T up to 1340 kg/m 3 . The total porosity of coals, determined by the heat of wetting, also changes according to a parabolic law; for Donetsk coal grade D it is 22-14%, coal grade K - 4-8% and increases (apparently as a result of decompaction) up to 10-15% coal grade T. Endogenous (developed in the process of coal formation) fracturing, estimated by the number of cracks for every 5 cm of shiny coal, controlled by the stage of coal metamorphism; it increases to 12 cracks at the transition of brown coals to long-flame ones, has a maximum of 35-60 for coke coals and successively decreases to 12-15 cracks at the transition to anthracites. Changes in the elastic properties of coals - Young's modulus, Poisson's ratio, shear (shear) modulus, ultrasound velocity - are subject to the same regularity. The main technological properties that determine the value of hard coals are caking and coking properties.
World geological reserves (resources) of hard coals are accounted for by several international organizations on the basis of various, in many respects difficult to compare parameters, as a result of which they lead to different results, ranging from 8 to 16 trillion m3. tons. Of the 14.8 trillion. tons of world geological reserves (resources) of natural fuels, coal accounts for 9.4 trillion. tons.
I remember in childhood at the age of "why" 3-4 years old, dad told me where coal, oil, gas and other natural resources come from. I recently read a post about "large holes in the earth". "What a giant hole in the ground looks like from a bird's eye view." Under the influence of what I read, decades later, this topic became interested again. To begin with, I suggest that you read this article (see below)
Trees, grass = coal. Animals = oil, gas. A short formula for the creation of coal, oil, gas.
Coal and oil are found between layers of sedimentary rocks. In essence, sedimentary rocks are dried mud. This means that all these seams, including coal and oil, were formed mainly due to the action of water during the flood. It should be added that almost all coal and oil reserves are of vegetable origin.
Coal (charred animal remains) and oil formed from animal remains contain nitrogen compounds that are absent in vegetable oil. Thus, it is not difficult to distinguish one type of deposits from another.
Most people are amazed to learn that coal and oil are essentially the same thing. The only real difference between them is the water content of the deposits!
The easiest way to understand the formation of coal and oil is to look at the example of a pie being baked in an oven. We all saw how the heated filling flows out of the pie onto a baking sheet. The result is a viscous or charred substance that is difficult to scrape off. The more the leaked filling tans, the harder and blacker it will become.
Here's what happens to the filling: sugar (a hydrocarbon) dehydrates in a hot oven. The hotter the oven, and the longer the cake bakes, the harder and blacker the lumps of leaked filling will become. In fact, the blackened filling can be considered a type of low-quality coal.
Wood is made up of cellulose - sugar. Consider what would happen if a large amount of plant material were quickly buried in the ground. During the decomposition process, heat is released, which will begin to dehydrate the plant material. Loss of water, however, will lead to further heating. In turn, this will cause further dehydration. If the process takes place under such conditions that the heat does not dissipate quickly, then heating and drying continue.
Heating up the plant material in the ground will lead to one of two results. If water can flow out of a geological formation that leaves dried and dehydrated material, then coal is produced. If the water cannot leave the geological formation, then oil will be obtained.
When moving from peat to lignite (brown coal), to bituminous coal and to anthracite, the water content in them (the degree of dehydration or the degree of water content reduction) changes in a linear relationship.
A necessary ingredient in the formation of fossil fuels is the presence of kaolin clays. Such clays are usually included in the products of volcanic eruptions, in particular in the composition of volcanic ash.
Coal and oil are obvious results of Noah's Flood. During the global catastrophe and the subsequent Noah's Flood, huge amounts of superheated water poured out of the depths onto the earth's surface, where they mixed with surface water and rainwater. In addition, thanks to hot rocks and hot ash from thousands of volcanoes, many of the sedimentary layers that formed were heated. Earth is a wonderful thermal insulator that can retain heat for a long time.
At the beginning of the Flood, thousands of volcanoes, shifts in the earth's crust mowed down forests all over the planet. Volcanic ash covered huge clusters of tree trunks that floated in the water. After these accumulations of trunks were buried between the heated sedimentary layers deposited during the Flood, in short time coal and oil were formed.
“Summary: industrial accumulations of oil and natural gas can form over several thousand years in sedimentation pools [dried mud layers] under conditions of hot liquid flow over comparable periods of time.”
The hot, wet mud beds created by Noah's Flood created ideal conditions for the rapid formation of coal, oil, and gas.
Required time to "create" coal, oil.
Laboratory research conducted in the last few decades have shown that coal and oil can form rapidly. In May 1972, George Hill, dean of the College of Mines and Mines, wrote an article published in the Journal of Chemical Technology, now known as Chemtek. On page 292 he commented:
“Luckily, this turned out to be a rather startling discovery... These observations suggest that high-grade coals during their formation... probably experienced high temperatures at some point in their history. Perhaps the mechanism for the formation of these high-grade coals was some event that caused a short-term sharp heating.
The fact is that Hill simply managed to make coal (indistinguishable from natural). And it took him six hours.
More than 20 years ago, British researchers invented a way to turn household waste into oil, suitable for heating houses and using it as fuel for power plants.
Natural coal can also form quickly. Argonne National Laboratory reports results scientific research proving that, under natural conditions, coal can form in as little as 36 weeks. According to this report, for the formation of coal, it is only necessary that the wood and kaolin clay as a catalyst be buried deep enough (to exclude oxygen); and that the temperature of the surrounding rocks be 150 degrees Celsius. Under such conditions, coal is obtained in just 36 months. Further, the message noted that with more high temperatures coal is formed even faster.
Oil is a renewable natural resource.
The big intrigue is that oil and natural gas reserves may not be as limited and finite as many imagine them to be. On April 16, 1999, a staff reporter for the Wall Street Journal wrote an article, "Not a Joke at All: An Oil Field Grows as the Oil Produces." It starts like this:
Houston - something mysterious is going on at Eugene Island 330.
This field, located in the Gulf of Mexico far from the coast of Louisiana, was thought to have declined in productivity many years ago. And for a while, it behaved like a normal field: following its discovery in 1973, oil production at Eugene Island 330 peaked at about 15,000 barrels a day. By 1989, production had dropped to around 4,000 barrels a day.
Then, unexpectedly ... fate again smiled at Eugene Island. The field, operated by Penz-Energy Co., is producing 13,000 barrels a day today, and probable reserves have skyrocketed from 60 to over 400 million barrels. What is even stranger is that, according to scientists studying the field, the geological age of the oil flowing from the pipe is quite different from the age of the oil that was pumping out of the ground 10 years ago.
So, it seems that oil is still being formed in the bowels of the earth; and its quality is higher than found originally. The more research is done, the more we learn that the forces of nature that produce new oil are still at work!
Conclusions.
Looking at the photos of huge coal pits, realizing the data on the reserves of oil fields, we can assume that:
Oil in ancient times was formed on the site of previously existing extensive forests, jungles. Those. where there are now the largest reserves of oil and coal in the world, there used to be impenetrable forests with gigantic trees. And all these forests at one moment turned out to be dumped into one huge heap, later littered with earth, under which, without air access, coal and oil were formed. In place of Siberia - the jungle, desert Kuwait, Iraq, United Arab Emirates, Mexico many thousands of years ago were covered with impenetrable forests.
In the event of a future apocalypse, our descendants, like us, in a few thousand years have a chance to possess the richest deposits of minerals. In addition to those that we do not have time to extract and process, new ones will appear. And we can say with confidence that they will be located geographically in the place of the current dense forests - again our Siberia), the Amazon jungle and other wooded places on our planet.
coal called sedimentary rock formed during the decomposition of plant remains (tree ferns, horsetails and club mosses, as well as the first gymnosperms). The main reserves of hard coal currently mined were formed during the Paleozoic period, about 300-350 million years ago. Coal has been mined for several centuries and is one of the most important minerals. Used as solid fuel.
Coal consists of a mixture of high-molecular aromatic compounds (mainly carbon), as well as water and volatile substances with a small amount of impurities. Depending on the composition of coal, the amount of heat released during its combustion, as well as the amount of ash formed, also changes. The value of coal and its deposits depends on this ratio.
For the formation of a mineral, it was also necessary to fulfill the following condition: rotting plant material had to accumulate faster than its decomposition occurred. That is why coal was formed mainly on ancient peatlands, where carbon compounds accumulated, and there was practically no access to oxygen. The source material for the emergence of coal is, in fact, peat itself, which was also used as a fuel for some time. Coal, on the other hand, was formed if peat layers were under other sediments. At the same time, peat was compressed, losing water as a result of which coal was formed.
Coal occurs when peat layers occur at a considerable depth, usually more than 3 km. At greater depths, anthracite is formed - the highest grade of hard coal. However, this does not mean that all coal deposits are located at great depths. Over time, under the influence of tectonic processes of various directions, some layers experienced uplift, as a result of which they turned out to be closer to the surface.
The method of coal mining also depends on the depth at which coal-bearing deposits are located. If coal lies at a depth of up to 100 meters, then mining is usually carried out in an open way. This is the name of the removal of the top above the deposit, in which the mineral is on the surface. For mining from great depths, the mine method is used, in which access to is carried out through the creation of special underground passages - mines. The deepest coal mines in Russia are about 1,200 meters below the surface.
The largest coal deposits in Russia
Elga field (Sakha)
This coal deposit, located in the southeast of the Republic of Sakha (Yakutia), 415 km east of the city of Neryungri, is the most promising for open development. The deposit area is 246 km2. The deposit is a gently sloping asymmetric fold.
The deposits of the Upper Jurassic and Lower Cretaceous are coal-bearing. The main coal seams are located in the deposits of the Neryungri (6 seams, 0.7-17 m thick) and Undyktan (18 seams, also 0.7-17 m thick) formations.
The coals here are mostly semi-glossy with a very high content of the most valuable component - vitrinite (78-98%), medium and high ash, low sulfur, low phosphorus, good sintering, with a high calorific value. Elga coal can be enriched using a special technology, which will make it possible to obtain a product of a higher quality that meets international standards. Powerful flat coal seams are covered with deposits of small thickness, which is very important for open pit mining.
Elegest deposit (Tuva)
Located in the Republic of Tuva. This field has reserves of about 20 billion tons. Most of reserves (about 80%) are located in one layer 6.4 m thick. The development of this deposit is currently ongoing, so coal mining here should reach its maximum capacity around 2012.
Large deposits of coal (the area of which is thousands of km2) are called coal basins. Typically, such deposits are located in some large tectonic structure (for example, a trough). However, not all deposits located close to each other are usually combined into basins, and sometimes they are considered as separate deposits. This usually happens according to historically established ideas (deposits were discovered in different periods).
Minusinsk coal basin is located in the Republic of Khakassia. Coal mining began here in 1904. The largest deposits include Chernogorskoye and Izykhskoye. According to geologists, the coal reserves in this area amount to 2.7 billion tons. Stone long-flame coals with a high calorific value predominate in the basin. The coals are classified as medium ash. The maximum ash content is typical for the coals of the Izykh deposit, the minimum - for the coals of the Beyskoye deposit. Coal mining in the basin is carried out in different ways: there are both cuts and mines.
Kuznetsk coal basin (Kuzbass) one of the largest coal deposits in the world. Kuzbass is located in the south in a shallow basin between the mountain ranges, Mountain Shoria and. This is the territory of the Kemerovo region. The abbreviation "Kuzbass" is the second name of the region. The first deposit in the Kemerovo region was discovered back in 1721, and in 1842 the term "Kuznetsk coal basin" was introduced by the geologist Chikhachev.
Mining here is also carried out in different ways. There are 58 mines and more than 30 cuts on the territory of the basin. In terms of quality, "" coals are diverse and are among the best coals.
The coal-bearing stratum of the Kuznetsk coal basin consists of approximately 260 coal seams of various thicknesses, unevenly distributed along the section. The predominant thickness of coal seams is from 1.3 to 4.0 m, but there are also thicker seams of 9-15 and even 20 m, and in some places up to 30 m.
The maximum depth of coal mines does not exceed 500 m (average depth is about 200 m). The average thickness of the developed coal seams is 2.1 m, but up to 25% of mine coal production falls on seams over 6.5 m.