Organic rocks. Organogenic sedimentary rocks

ORGANIC ROCKS (from the Greek organon - organ and -genes - giving birth, born, biogenic rocks * a. organogenic rocks, biogenic rocks; and. organogene Gesteine; f. roches organogenes, roches biogenes; I. rocas organogenicas) - sedimentary rocks consisting of the remains of animals and plants and their metabolic products. Organisms have the ability to concentrate certain substances that do not reach saturation in natural waters, forming skeletons or tissues that are preserved in a fossil state.

According to the material composition, carbonate, siliceous, and some phosphate rocks, as well as coals (see), oil shale, oil, and solid bitumen, can be distinguished among organogenic rocks. Organogenic carbonate rocks () consist of shells of foraminifers, corals, bryozoans, brachiopods, mollusks, algae and other organisms.

Their peculiar representatives are reef limestones that make up atolls, barrier reefs and others, as well as writing chalk. Siliceous organogenic rocks include: diatomite, spongolite, radiolarite, etc. Diatomites consist of opal skeletons of diatoms, as well as spicules of flint sponges and radiolarians. Spongolites are rocks containing usually more than 50% spicules of flint sponges. Their cement is siliceous, of opal rounded bodies, or clayey, slightly calcareous, often including secondary chalcedony. Radiolarites are siliceous rocks, more than 50% consisting of radiolarian skeletons, which form radiolarian silt in modern oceans. In addition to radiolarians, they include sponge spicules, rare diatom shells, coccolithophores, and opal and clay particles. Many jaspers have a base of radiolarians.

Phosphate organogenic rocks do not have widespread. These include shell rocks from phosphate shells of Silurian brachiopods - obolid, accumulations of bones of fossil vertebrates (bone breccias), known in deposits different ages, as well as guano. Organogenic carbonaceous rocks - fossil coals and oil shale - are common, but their mass in the earth's crust is small compared to carbonate rocks. Oil and solid bitumen are peculiar rocks, the main material for the formation of which was phytoplankton.

According to the conditions of formation (mainly in relation to carbonate rocks), bioherms can be distinguished - the accumulation of the remains of organisms in their lifetime, thanato- and taphrocenoses - the joint burial of dead organisms that lived here or were carried by waves and currents; rocks that have arisen from planktonic organisms are called planktonic (for example, diatomite, chalk, foraminiferal limestone).

If organic remains are crushed as a result of the action of waves and surf, organogenic-clastic rocks are formed, consisting of fragments (detritus) of shells and skeletons held together by some mineral substance (for example,).

Stones of organic origin - a selection of stones, photos, properties, origin

Stones born of life

They say about the stone "cold", "dead", "lifeless". But life on Earth is not much younger than the planet itself, and many terrestrial minerals are formed by living organisms. Oil, according to modern concepts, is a visible trace of the existence of microscopic unicellular plants and animals of the distant past. Coal was considered by ancient naturalists to be the brother of oil. Chalk, limestone, marble are the life products of sea creatures...

This is where the list of minerals of biogenic origin that comes to mind to the average person usually ends. However, a knowledgeable mineralogist could go on and on with the list of rocks that appeared on Earth solely due to the existence of life.

Even gemology, the science of precious stones, is ready to present an impressive list of gems, each of which was once alive. Jewel Popularity Champion biological nature- pearls!

Mother of pearl - half brother of pearls

It just didn't come out in shape. If a pearl is a spherical formation (or close to a sphere in shape), then it is only deposited on the walls of the shell.

The demand for mother-of-pearl has always exceeded the demand for pearls due to the low price and wide availability of the material. Pearls are rare, and there are tons of mother-of-pearl in any river. Mollusk shells, covered with a thick layer of mother-of-pearl, have been used to make buttons, combs, handles and other consumer goods for many centuries. Today there is no type of plastic that would be used as widely and actively as mother-of-pearl in the recent past.

Once palm trees grew everywhere

...because it was warm and humid. The petrified palm stem can be found in coal deposits, in shale, and in quartz deposits. It is silicates that make palm wood an aesthetically expressive stone.

It should be noted that in its botanical essence, the palm tree is a tree-like, but herbaceous plant. You can't find annual rings on palm trees! On the other hand, the longitudinal vessels, through which the nutrient juices circulated throughout the plant, are very clearly visible. They - both on the transverse and on the longitudinal cut of petrified palm wood - make up the beauty of the stone.

The soft starchy core of the palm trunk is not rich in vessels, and therefore is replaced during fossilization by a homogeneous siliceous material.

Various silicas, impregnating the trunks of flooded, covered, drowned trees in swamps, often turn unremarkable wood into a precious gem. Silicates, colored with a variety of mineral impurities, acquire an iridescent color. A chip, saw cut, and even better, a thin section often amazes with the richness of the natural palette of colors.

In this case, the layered wood structure remains, as a rule, well distinguishable. What only adds decorativeness to the most beautiful stone of biological origin.

Stromatolite jaspers

Jasper Rock Mary Ellen is located in the state of Minnesota (USA). It is famous for the fact that the main masses of the rocks that make up the mountain - red jasper and silver hematite - are intertwined in unimaginable clubs and twists.

Red and black is an advantageous color combination for any artistic subject. However, stromatolites, formed from layered colonies of cyanobacteria two billion years ago, rarely turn red. Only on the American continent were found traces of the first steps of life on the planet, made by red jasper on black iron ore...

petrified corals

A polished petrified one makes you want to blow off dust particles from it - the jewelry work of nature is so fine. Cellular frameworks of marine organisms of the distant past are delicately arranged and skillfully "executed". The resemblance of fossil coral to the work of a skilled craftsman is endless!

Quartz and calcite, replacing organic tissue in fossilized corals, make jewelry durable. However, the bright colors characteristic of modern corals are not found in fossil polyps. Fiery red or transparent yellow earrings made of petrified corals are the product of handicraft "improvement".

"Sand Dollar"

"Sand dollar" in both Americas is called the skeleton sea ​​urchin, classified as incorrect (such is zoological terminology). Correct hedgehogs are round echinoderms, incorrect ones are flat. They have been living on Earth for a long time, and in some places they inhabit the shelf bottom so densely that they lie on the sand like scales on the body of a crucian carp - or even in two layers.

Wrong hedgehogs they have a very conditional needle protection, and therefore everyone who is not lazy feeds on them. Nevertheless, many of the flat as a toy saucer animals manage to grow a decent thickness of the skeleton, live to a natural death and please people with the sight of their skeleton - the "sand dollar". Especially highly valued are dollars "issued" millions of years ago...

Ammonites

Anyone who has been interested in the history of evolution knows about the ammonites. They - sometimes quite modest in size, sometimes under two meters in diameter - are twisted into a flat spiral, like the horns of the god Amun in one of his earthly incarnations. Ammonites are easy to find in natural screes. In some European countries, they have long been called "golden snails".

Ammonite "gold" is a layer of petrified mother-of-pearl in sealed shell chambers. The most beautiful ammonites are mined in the Canadian province of Alberta. The iridescent radiance of the polished walls of the shells surpasses the play of color in opal and labradorite.

dinosaur bone

The process of bone petrification is extremely lengthy, because each molecule of calcium phosphate (of which, in fact, bones are composed) must be replaced by a molecule of silicon dioxide. It takes at least two million years for a medium-sized dinosaur skeleton to turn into a precious gem!

Fortunately, something, but dinosaur bones have enough time with a large margin. For 65 million years separating us from the last animal lizards of the Earth, many tons of bones turned into colored quartz. Moreover, a considerable part of quartz took on impurities, which allowed the hitherto unattractive natural material to acquire both the look, the pattern, and the texture at a good jewelry level. Dinosaur bone cabochons are often extremely attractive!

Ivory is younger than dinosaur bones. Today, under the name of "ivory" distinguish the tusks of African and Indian elephants, fossil mammoths, walrus fangs, hippo and sperm whale teeth.

The main thing is its luxurious appearance. However, the manufacturability of the material is also important. Last but not least, artisans fell in love with ivory because of its ability to become plastic, and then harden again.

Ivory color varies. The white and blue tooth of a hippopotamus, warm shades (up to red-brown) of mammoth tusk, translucent whiteness of the tusk of a young elephant are valued.

The list of stones of biological origin can go on and on. The gallery of precious gems is replenished by the efforts of geologists, researchers, pioneers of remote areas of the planet.

Like the glow of dawn

The first pearls people found in search of food. Oysters producing this gem are still loved by gourmets. For thousands of years, people have been admiring the radiance of pearls that have grown by the will of nature - and for several decades now we have been forcing mollusks to envelop seed grains of sand in multi-colored layers.

Today's pearls are all colors of the rainbow and even the colors of the night! But, as in the old days, this is a stone in which at least half of the mass falls on organic tissue. We examined pearls in more detail in the article, and you can be sure that this stone of biological origin has been in favor of fashionistas for the fifth millennium in a row!

Frozen sunshine...

... poetically called amber. Both honey-transparent and the most “foggy” forms of the stone really give the impression of clots of luminous substance. There are countless varieties of amber! The color range of this natural jewel ranges from milky white through all shades of yellow and red to blue and green. There are amber and black!

Every amber is a piece of fossilized resin of a tree that grew millions of years ago. There are ambers born in pine groves, and ambers derived from resin tropical trees. We talked about amber in the articles: and. Now the time has come to pay attention to the trees that grew hundreds of millions of years ago, and by our time have turned into "precious stones".

"Peanut" wood

Wood with a clear structuring of the array during fossilization can also give an unexpected visual effect. Particularly interesting are the fossilized wood remains that have spent many years under water. The point, in fact, is not in the water, but in the mollusks that inhabit the reservoirs of the planet. Some of them feed on rotting wood, and in the process of obtaining food they go deep into the flooded logs, gnawing through numerous passages.

The subsequent mineralization of organics led to a striking result. The cavities gnawed (more precisely, machined) by the mealybug were filled with white quartz. The fabrics of the tree remained colored. Minerologists dubbed this kind of petrified wood "peanut forest" - for the similarity of the stone pattern with sprouting peanuts is almost one hundred percent.

Jet

However, not all plant remains of the distant past are so lucky. Jet, a mineral related to coal, is recognized as the same prehistoric wood that survived flooding in the silt layers two hundred million years ago.

Unattractive in its raw form, polished jet shines like silk velvet. The best grades of stone are distinguished by a mirror gloss and are used to make jewelry. In the recent past, a lot of haberdashery trifles were made from jet - like buttons, beads, beads. served its owners no worse than mother-of-pearl.

corals

Most of the bottom marine sediments are formed by the calcareous remains of organisms that lived in ancient times. However, corals, having won a warm place five hundred million years ago, thrive to this day.

Calcareous skeletons of corals have three and a half hundred variants of natural coloration. Polished coral is an excellent material for making jewelry. However, the user must remember: the thicker the color of the coral, the more organic matter it contains, and the more careful the subject should be treated.

Modern types of corals are different from the polyps that inhabited the earth's seas in past geological epochs. However, we can say with confidence: petrified corals are extremely beautiful and interesting!

Compressed carcasses of sea lilies

Crinoid sea lilies once so abundantly inhabited the shallow bottom of the warm seas that their calcareous cores - mostly tubular, divided into short segments - became a rock-forming element. Many of the most interesting specimens of these Proterozoic pufferfish were obtained during the construction of the Moscow Metro.

However, crinoidal limestone, formed by the remains of flower-like animals three hundred million years ago, is not found under (literally) Moscow. Although this mineral is widely distributed.

Distinguishable remains of crinoids, “soldered” into the thickness of a translucent mineral, are sometimes very decorative. Such stones become a worthy decoration.

Under the sonorous name lies a beautiful mineral with an unusual history. In fact, turritella terebra is the name of a marine mollusk with a helical shell. They say that it was turitella shells that prompted the legendary Archimedes to construct a water-lifting propeller.

Turitella agate is, in fact, a scattering of shells of a mollusk of this species, which are in varying degrees of preservation, filled with hardened silicate. Many of the real turitell agates include sand, water, air bubbles.

Take a look at the outside precious stone! Under the name of agate-turitella, any petrified garbage is often sold. If you do not see distinctly preserved elements of cone-spiral shells, this is a fake!

Organogenic sedimentary rocks

1. Sedimentary organogenic rocks

On the surface of the Earth, as a result of the action of various exogenous factors, sediments are formed, which are further compacted, undergo various physicochemical changes - diagenesis, and turn into sedimentary rocks. Among the sedimentary rocks, three groups are distinguished: clastic rocks resulting from the mechanical destruction of any rocks and the accumulation of the resulting debris;) clayey rocks, which are the product of predominantly chemical destruction of rocks and the accumulation of clay minerals that have arisen in this case;) chemical (chemogenic) rocks, formed as a result of chemical processes;) organogenic rocks formed as a result of biological processes.

Sedimentary organogenic rocks will be discussed. Organogenic rocks are sedimentary rocks formed from the accumulation of waste products and undecomposed remains of living organisms: shell limestone, fossil coals, guano - decomposed droppings of seabirds, etc.

When describing sedimentary organogenic rocks, one should pay attention to their mineral composition, which is a defining feature, and to their structure. Also, the most important feature characterizing the structure of sedimentary rocks is their layered texture. The formation of layering is associated with the conditions of sediment accumulation. Any change in these conditions causes either a change in the composition of the deposited material or a stop in its supply. In the section, this leads to the appearance of layers separated by bedding surfaces and often differing in composition and structure. The layers are more or less flat bodies, the horizontal dimensions of which are many times greater than their thickness (thickness). The thickness of the layers can reach tens of meters or not exceed fractions of a centimeter.

1.1 Origin

The formation of sediments, from which sedimentary rocks arise, occurs on the surface of the earth, in its near-surface part and in water basins.

The process of formation of sedimentary rock is called lithogenesis and consists of several stages:

) formation of sedimentary material;

) transfer of sedimentary material;

) sedimentogenesis - sediment accumulation;

) diagenesis - the transformation of sediment into sedimentary rock;

) catagenesis - the stage of existence of sedimentary rock in the zone of the stratisphere;

) metagenesis - the stage of deep transformation of sedimentary rock in the deep zones of the earth's crust.

The bulk of organogenic rocks originated in marine and continental water bodies of different salinity, depth and size, as well as as a result of the action of chemical processes and the vital activity of organisms on land and sea. All rocks of chemogenic and organogenic origin are connected by mutual transitions and have a mixed chemogenic-organogenic origin. Classification of rocks of chemogenic and organogenic genesis is carried out according to the chemical composition.

Consider the formation of some organogenic rocks. For example, limestone. Huge deposits of limestone, formed millions of years ago from the skeletons of marine animals, account for approximately 20% of the total amount of sedimentary rocks. Limestones were formed as a result of long-term geochemical processes. Rivers annually carry out into the sea many millions of tons of lime in the form of suspension and in dissolved form. When river water meets sea salt, a kind of “geochemical barrier” is formed, on which soluble compounds, including lime, precipitate, mixing with silt. Part of the calcium bicarbonate remains in a dissolved state and is gradually absorbed by marine plants and animals. As a result, over millions of years, a huge number of shells of dead mollusks and corals formed colossal accumulations of calcium carbonate. Thus, various limestones arose, among which, according to rock-forming organisms, coral, shell, nummulite, bryozoans, algae, and others are distinguished.

Rice. 1. Formation of an oil deposit

Or the formation of another organogenic rock, such as oil. (Fig. 1) The main conditions for the development of the process of oil formation, called thermal catalysis, are the subsidence of sedimentary rocks containing organic residues to great depths, the impact of high temperatures and pressures prevailing at these depths, and the catalytic role of the host rocks themselves, accelerating the reactions of decomposition and chemical processing of organic substances. When oxidized on the surface, the oil passes into kirs and asphalts.

Another example is the formation of oil shale. Education begins from the moment of accumulation of organic residues. The "parents" of shales are the smallest algae moved by waves or (phytoplankton), sometimes algae of underwater meadows (phytobenthosis) or the lowest representatives of the animal world (fiankton). Oil shales began to form 130-140 million years ago in the Lower Volga Age jurassic. The Jurassic seas were shallow, warmed up well and were densely populated with algae, which served as a habitat for numerous invertebrates and vertebrate organisms. After death, the organisms sank to the bottom into a silty-argillaceous sediment, which served as the basis for the formation of oil shale. If you break off a piece of oil shale, you can see a large number of imprints of algae, passages of worms, ammonites, belemnites, bivalves, scales of fossil fish, vertebrae of ichthyosaurs, plesiosaurs and other organisms.

Rice. 2. Coal formation

The variety of types of vegetation that grew on Earth in different geological epochs and in different climatic zones, the conditions of burial and transformation in peat deposits determined the widest range of properties of the organic mass, which was the source material, and subsequently became direct coal. The formation of peat deposits took place (and is happening now) in swamps of various types: in coastal-sea, lake, river valleys. Peatlands were periodically flooded with waters with which a certain amount of mineral impurities was introduced, both in suspended and chemically dissolved states. The intensity of their supply and the composition of the rocks surrounding the peatlands determined the ash content of coal and the presence in its composition of harmful and useful chemical elements, such as sulfur, phosphorus, germanium, allium, etc. Further, the peatlands were covered by a thickness of the so-called sedimentary rocks due to the bowing of the Earth's crust and sank to various depths, where, under conditions of significant pressures and temperatures, the original organic matter acquired the properties inherent in one or another brand of coal.

1.2 Classification

Organogenic rocks (biogenic rocks) - consist of the remains of animals and plant organisms or their metabolic products.

Organisms have the ability to concentrate certain compounds, forming skeletons or tissues that are preserved in the fossil state. According to the material composition, among the organogenic rocks, one can distinguish:

) carbonate;

) siliceous;

) phosphate;

) oil shale;

I propose to consider each group separately.

Organogenic carbonate rocks (limestones) consist of shells of foraminifers, corals, bryozoans, brachiopods, molluscs, algae, and other organisms. Their peculiar representatives are reef limestones that make up atolls, barrier reefs, etc., as well as chalk.) Reef limestones - At present, most of the reefs are built by corals, but hundreds of millions of years ago, the main builders of reefs were bryozoans (colonial aquatic, mainly marine, attached animals) and algae.) Chalk is a soft limestone with a very fine texture, which is usually white or light gray in color. It is formed mainly from calcareous remains of microscopic marine organisms such as foraminifera or calcareous remains from numerous kinds seaweed.

Siliceous rocks are composed of hydrous silica (opal). Among them, they distinguish:) Diatomite - formed from the shells of diatoms and partly from the skeletons of radiolarians and sponges, between which the finest silt and clay were deposited. It consists mainly of amorphous silica in the form of the mineral opal.) Spongolites are rocks containing usually more than 50% spicules of flint sponges. Their cement is siliceous, from opal rounded bodies, or clayey, slightly calcareous, often includes secondary chalcedony.) Radiolarites are siliceous rocks, more than 30% consisting of radiolarian skeletons, which form radiolarian silt in modern oceans. In addition to radiolarians, they include single sponge spicules, rare shells of diatoms, coccolithophores, and opal and clay particles. During recrystallization, radiolarites turn into jaspers.) tripol - a rock of predominantly colloid-chemogenic origin, consisting of the smallest grains of opal;) flask - a hard siliceous rock formed as a result of recrystallization and cementation of diatomite or tripoli.

Organogenic phosphate rocks are not widespread. These include shell rocks from phosphate shells of Silurian brachiopods - obolid, accumulations of bones of fossil vertebrates known in sediments of different ages, as well as guano - decomposition products of bird droppings, the thickness of which usually accumulates on islands in a dry climate.

Coal forms from the accumulation and conservation of plant materials, usually in swamps. Coal is a combustible rock and together with oil and natural gas is one of the three most important fossil fuels. Coal has a wide range of uses, the most important being the use for electricity generation.

Depending on the stage of metamorphism in Russia, these types of coal are distinguished. (Table 1)

Table 1. Stages of coal metamorphism

	Properties
	Peat is the initial product for the formation of coal. Contains 50-60% carbon. It accumulates in swamps from the remains of dead plants that have undergone incomplete decomposition in conditions of high humidity and difficult air access. The layer of peat in swamps is at least 30 cm (if less, then these are wetlands).
Brown coal	Brown coals are solid fossil coals, which were formed from peat and consist of 65-70% carbon. This type brown color is the youngest among all fossil coals. It is formed under the influence of high load and elevated temperature from organic dead remains at a depth of about 1 kilometer.
Coal	Coal is a sedimentary rock formed from the deep decomposition of various plant remains (horsetails, the first gymnosperms, tree ferns and club mosses). The chemical composition of this coal is a mixture of polycyclic macromolecular aromatic compounds with a high concentration of carbon and less - water, volatile substances and mineral impurities that form ash when coal is burned. Some organic substances that make up such coal are carcinogenic. Hard coals are formed from brown coals at depths of about three kilometers. It has a high calorific value due to the content of 8-20% moisture and, depending on the variety, from 75% to 95% carbon.
Anthracite	Anthracites are coals of the highest degree of coalification. Differ in the high density and gloss. Carbon contain 95%. They are formed under the influence of temperature and pressure from coal at a depth of about 6 kilometers. They are used as a solid high-calorie fuel, since they have the highest degree of calorific value, but at the same time they ignite poorly.

Oil shale is a mineral occurring at relatively shallow depths, belongs to the group of solid caustobiolites and consists of organic matter (10-50% by weight) and a mineral part. Both organic and mineral parts of shales are of industrial value, the main components of which are carbonates and aluminosilicates. Oil shales are thin-layered, have a dark gray or brown color, emit the smell of bitumen when burned.

Oil is an organogenic rock. The source material for the formation of oil is putrefactive silt, or sapropel, accumulating at the bottom of stagnant water bodies: lakes, sea bays, lagoons, sometimes also in coastal areas of the bottom of open sea basins as a result of the death of various lower plants and animals, mainly planktonic microorganisms inhabiting the waters of the seas and oceans.

Organogenic rocks can also be divided by structure. In these breeds, the shape is of great importance. constituent parts, which is determined by the nature of organisms. Among the rocks of this group, structures are distinguished: crinoid, coral, pelecypod, bryozoan, foraminiferal, algal, mixed, etc. Depending on the safety of the fragments in the rock, the following structures are distinguished:

Biomorphic - good preservation of organic remains. In terms of the size of the components, they can be very different depending on the organisms - from very large (for example, corals) to the smallest (for example, diatoms);

Detritus (detritus) - the rock is composed of fragments of the skeletons of organisms.

In turn, among the rocks with a detritus structure, they distinguish:) large-detritus rocks are composed of unrounded fragments, often clearly visible to the naked eye and easily identifiable under a microscope. The size of the fragments most often varies from a few millimeters to about 0.05 mm.) small-detritus. composed of the smallest fragments of organisms (usually from 0.05 mm and smaller), indistinguishable with the naked eye and for the most part not detectable under a microscope in thin section.

The organogenic-detrital structure differs in that shell fragments for the most part well rounded and almost the same size (0.5 -0.1 mm).

2 . Distribution of organogenic rocks in the Krasnodar Territory

More than 60 types of minerals have been discovered in the bowels of the region. They mainly occur in the foothills and mountainous regions. There are reserves of oil, natural gas, marl, iodine-bromine water, marble, limestone, sandstone, gravel, quartz sand, iron and apatite ores, rock salt and other minerals. The Ministry of Natural Resources of the Russian Federation approved a list of common minerals Krasnodar Territory below is a list of some of them:

diatomaceous earth;

Limestones;

Marl;

shell rock;

Shales (except combustible);

Peat (except used for medicinal purposes).

2.1 Deposits in the Krasnodar Territory

Hydrocarbon and energy raw materials

Hydrocarbon and energy raw materials. 280 oil and gas fields (Fig. 3) and gas have been discovered on the territory of the region. Oil deposits are located in the thickness of sedimentary rocks and are located at a depth of 700 to 5200 m. According to geological services, by 1995, 218 million tons of oil had been produced in the region. Of the more than 70 explored oil fields with a reserve of 41.8 million tons, 66 are in operation. The forecast estimate of oil reserves is approximately three times higher than the explored ones.

An example of one of the largest oil fields Novodmitrievskoe (Seversky district) can serve: it has a length of about 10 km, a width of 2.5 km, and the thickness of oil-bearing rocks (oil-bearing level) is 450 m. Oil occurs here at a depth of 2400-2800 m.

Coal deposits are found in mountainous areas in the basins of the Belaya, Malaya and Bolshaya Laba rivers. Coal occurs in the form of seams with a thickness of 0.5-0.9 m. But due to the low calorific value, the extraction of Kuban coal is not profitable.

Manifestations of oil shale of low and medium quality were found in the interfluve of the Bolshaya and Malaya Laba. According to geologists' forecasts, shale reserves amount to 136.25 million tons. Peat deposits are found in the lower reaches of the Kuban (Grivenskoye), in the Novokubansky district along the river. Urup, as well as at the mouth of the Mzymta and Psou rivers on Black Sea coast. The development of oil shale and peat deposits is also unprofitable due to their low energy value and small reserves.

Limestones

Limestones and chalk are widely used in the chemical industry for the production of soda, calcium carbide, caustic potash, caustic soda, in the production of mineral fertilizers and other products. On the territory of the Krasnodar Territory, one (Pravoberezhnoye) limestone deposit is known. It is located in the Labinsk region, on the right bank of the river. Malaya Laba, 4 km east of the railway. station Shedok. The useful strata are the limestones of the Turonian and Coniacian stages of the Upper Cretaceous, the thickness of which varies from 0 to 73 m. The chemical composition of the limestones of the productive strata (in%): CaO - 54.2; MgO - 0.3; SiO 2 - 1.4; R 2 O 3 - 0.7; Na 2 O - 0.04; K 2 O - 0.07; SO 3 - 0.1; P - 0.024. According to their properties, limestones are suitable for soda production, and can also be used in the sugar industry and for the production of lime and cement. Stocks of raw materials amount to 244314 thousand tons.

Sea shell

Seashell deposits in the Krasnodar Territory are confined to the coast of the Sea of ​​Azov and its estuaries and, to a lesser extent, the estuaries of the Taman Peninsula. Genetically, they are modern marine sediments washed up by sea currents and surf along the coastline in the form of swells and spits. Such accumulations of sea shells have a width and length of several kilometers and a thickness of several meters. The main component in the composition of seashell deposits are calcareous shells (whole or fragments) of modern mollusks containing small amounts of sand, clay, organic residues, etc. for lime firing, for making wall blocks and for making fodder meal and cereals.

In the Krasnodar Territory, 33 seashell deposits have been described. Of these, only 6 deposits are on the balance of reserves (Kirpilskoye, western area; Slobodkinskoye, Khanskoye, Dolzhanskoye; Zaboyskoye and Chernoerkovskoye) with total reserves equal to 4220 thousand m 3 . Of these, Kirpilskoye, Zaboyskoye and Chernoerkovskoye deposits are being developed. They are located on the territory of the Yeysk and Primorsko-Akhtarsky districts. Raw materials of all listed deposits are suitable for use as fodder flour and cereals.

The largest in the Krasnodar Territory is the Dolzhanskoye seashell deposit. It is located in the Yeiskomraion, 3 km northwest of the village of Dolzhanskaya and 45 km west of the city of Yeysk, on the Dolgaya Spit. The useful stratum is composed of Middle Quaternary and modern marine sediments, represented by whole and crushed seashells, with an admixture of sand. Shell accumulations occur in a sheet-like manner in the form of a spit 4 km long and 30 to 1200 m wide; the thickness of the useful thickness is 2.65-6.1 m. Shell deposits are suitable for feeding birds. The deposit is a reserve.

building stone .

There are 41 deposits of building stone in the Krasnodar Territory. 25 deposits are being developed, 7 are being prepared for development, one is being explored and 8 are in reserve. Such deposits are known as: Medvezhyegorsk (6 km from Derbentskaya), Severnaya Gora (4 km from Ilskaya), Pravoberezhnoye (4 km from Shedok), Khodzhokhskoye (12 km from Kamennomostsky). The total reserves of building stone are 213.15 million m³, while the reserves of limestone used to produce crushed stone and rubble stone are 118.886 million m³; reserves of sandstones suitable for obtaining crushed stone - 39.123 million m³. Limestones are also used for the needs of sugar production.

2.2 Mining of the main organogenic rocks in the Krasnodar Territory

Krasnodar region is the birthplace of the domestic oil industry. 1.7 - 1.9 million tons of oil are annually extracted from the bowels of the region, natural gas production has been increased to 3 billion m³. The table below shows how oil production in the Kuban has grown steadily, with the exception of the war years and the period of the economic crisis of the 90s of the XX century.

Table 2. Growth rates of oil production in the Kuban

All currently developed oil fields in the Krasnodar Territory are located on land. Oil production in the region from small deposits amounted to 74%, and from the Anastasievsko-Troitskoye large field - 26% of the annual volume. Behind last years The largest increase in reserves and production of oil (and gas) is provided by prospecting and exploration of the Pribrezhno-Sladkovsko-Morozovskaya group of fields (33.8% of the annual volume of oil production). The average supply of oil reserves in the region, at the current level of production, is about 22 years.

The preparation of new commercial hydrocarbon reserves in the region, at the present stage, is complicated by the fact that the search is carried out mainly on small and complex deposits, with access to significant depths, in areas with difficult mining and technical conditions.

The main explored deposits on the territory of the region are at the final stage of development. The Krasnodar Territory is one of the oldest oil and gas producing regions in Russia. Most of its deposits with the main reserves of raw materials were put into operation more than 30-40 years ago and continue to be exploited to this day.

The main region of the coal industry is the eastern wing of the Donbass in the Rostov region. (Shakhty, Novoshakhtinsk, etc.). Coal production is about 7 million tons (2% of the total Russian production)”. Coal (coking and energy) is mined at great depths in conditions of low seam thickness, which leads to high cost and a limited (south of Russia) market for these coals. A further decline in production is unlikely to be stopped, as the conditions for production are difficult, and rich deposits have already been developed.

Unwanted limestone mining is underway on the eastern slope

Rice. 4. Limestone mining

Dzykhrinsky karst massif, in the 24th quarter of Sochi national park(Fig. 4), which is included in a specially protected area. Here, on the rocks of the Shakhginsky gorge, several species of plants grow, listed in the Red Book of Russia and the Krasnodar Territory. The quarry is developed with the help of excavators, the stone is loaded onto dump trucks and transported to a crusher located above Yermolovka.

3 . Applications in industry, construction and agriculture

Sedimentary rocks are of exceptional practical and theoretical importance. In this respect, no other rocks can compare with them.

Sedimentary rocks are the most important in practical terms: these are minerals, foundations for structures, and soils.

The scientific and practical significance of coals and oil shale is exceptionally great: they and their components are used for periodization of the history of the Earth, in stratigraphic studies (correlation of sections and age determination), facies analysis and paleogeography, in stadial analysis by the reflectivity of vitrinite, etc.

The practical importance of coal cannot be overestimated. It is primarily the main source of energy. Only since the mid-1950s, coal has given way to oil, but there has already been a tendency to re-enter the lead, and such a prospect is provided by the huge coal resources on Earth (almost 15 or even 30 trillion tons), which are an order of magnitude greater than the resources of oil and gas, taken together (Golitsyn, Golitsyn, 1989, p. 42). With an imminent reduction in oil production, oil shale (HS) will act as a substitute for it, “the total world reserves of which are 450 trillion. tons” (UN, 1967), which is an order of magnitude greater than the reserves of coal and oil (92 billion tons), although this number also included the predominant inorganic part in their composition. The HS contains from 26 to 53 trillion. tons of shale resin (according to various estimates; Golitsyn, Prokofieva 1990, p. 15), if 4% is taken as the lower limit of the resin content (and the upper reaches 35% in the Baltic kukersites and in the Glen Davis deposit in Australia). More than half (53%) of HS resources are concentrated in the US, especially in the richest Green River Basin (Rocky Mountains). Only from coal, if all of it is mined, it is possible to build a cube with an edge of 21 km (a volume of more than 10 thousand km3, which is almost 3 times higher than Everest (Golitsyn, Golitsyn, 1989, p. 42). The coal resources are calculated up to depths of 1800 m (sometimes up to 2000 m), brown - 600, lignites - 300 m.

Oil shale has been used as a fuel since at least 1694. As a source of energy, they are the hope of mankind. Their heat of combustion is from 4-5 to 20-25 MJ/kg (Golitsyn, Prokofieva, 1990, p. 7). By calorific value (more than 15 mJ/kg), tar yield (up to 25-30%), low sulfur content (less than 1%), low ash content and humidity, Baltic kukersites are the best in the world. Shale burning is limited by their sulfur content, which reaches 10% (poisoning of nature with sulfuric acid), and high ash content and humidity (up to 30%). Shale is a valuable chemical raw material, especially because of the high content of phenols, which are difficult to obtain from oil. Dictyonema shales of the Baltic States are interesting for the content of molybdenum, vanadium, silver, lead, copper and other rare and trace elements (Golitsyn, Prokofieva, 1990, p. 25, etc.).

Peat is a unique material. Despite the fact that it has been known for many hundreds of years and has been actively used by mankind in industry as a fuel and in agriculture as a fertilizer, only recently have the unique properties of peat been discovered. Peat turned out to be an unsurpassed natural antiseptic and a fantastically excellent raw material for the production of natural fabrics.

Its vast and constantly renewed reserves can be regarded as gigantic deposits of a unique sorbent material.

Peat can in large numbers refine oil into a harmless substance. During the tragedy in the Gulf of Mexico, it was simply necessary to fill the spot in large quantities with peat, which could turn into silt, which would stimulate the growth of algae.

Peat is practically not used for cleaning Wastewater from metals and organics, although its low cost and high purity may make it the most sought-after material in the world. Moreover, the sorption spectrum of metals is very wide from lithium to uranium. Almost all toxic organic substances can be captured by peat.

The practical significance of carbonatoliths is that they are all minerals. Limestone, chalk and dolomite are used in ferrous and non-ferrous metallurgy, the chemical industry, in the production of cement and other binders, for the production of rubber, glass, sugar, limestone flour for reclamation of acidic soils, mineral feeding in animal husbandry and poultry farming, as well as in other industries where the requirements for carbonate raw materials are determined mainly by its chemical and mineral composition. Due to the significant distribution and variety of properties, carbonate rocks are used in large volumes in various industries and agriculture. Also, one of the main consumers of carbonate rocks is the construction industry. It is used for finishing facades (Fig. 5), for the manufacture of various sealants, putty and plaster mixtures. The total number of explored reserves of carbonate raw materials, taken into account by various balances of reserves in Russia, currently exceeds 60 billion tons, more than 1900 deposits have been explored, about 570 are being developed.

Siliceous rocks (diatomites, tripoli, flasks), due to the presence of amorphous active silicic acid in their composition, have a number of very valuable properties: a finely porous structure, a relatively low bulk density and thermal conductivity. The combination of these properties predetermines their effective use in production. building materials(Fig. 6) and in particular in the production of ceramic products. Experience shows that the use of siliceous and clay rocks in a mixture with coal-containing waste can significantly improve the physical and mechanical properties of ceramics by creating a reducing environment during firing and the transition of ferric iron into a more fusible ferrous one, which ensures more intensive sintering when the temperature drops by 100 - 1500C.

Conclusion

The purpose of this course work was to explore this type of sedimentary rocks as organogenic. The goal was achieved - the origin, composition and features, as well as the main deposits in the Krasnodar Territory, were considered.

Despite the variety of organogenic rocks, the most common and most important ones are present in the work.

More than three-quarters of the area of ​​the continents is covered with sedimentary rocks, so they are most often dealt with in geological work. In addition, the vast majority of developed mineral deposits, including oil and gas, are associated with sedimentary rocks. The remains of extinct organisms are well preserved in them, by which one can trace the history of the development of the Earth. Organogenic rocks are also widely used in many industries, construction and agriculture.

On the basis of the work done, it can be concluded that organogenic rocks used by man have unique and useful properties that make these rocks relevant today.

Bibliography

sedimentary mountain petroleum organogenic

1. Kuznetsov V.G. Lithology. Sedimentary rocks and their study. - M.: Nedrabusinesscenter, 2007.

2. Sokolovsky A.K., Korsakov A.K., Fedchuk V.Ya. etc. General geology. M.: KDU, 2006.

3. Krasilshchikov Ya.S. Fundamentals of geology, prospecting and exploration of mineral deposits. - M.: Nedra, 1987.

4. Shvanov V.N., Frolov V.T., Sergeeva E.I. and other Systematics and classification of sedimentary rocks and their analogues. St. Petersburg: Nedra, 1998.

Rocks are minerals and their compounds. It is impossible to imagine our planet without the minerals that actually form it.

Classification system

There are a huge number of species of rocks, divided into groups. Genetically distinguished:

• sedimentary;
• metamorphic;
• magmatic.

The latter are further divided into three classes:

• plutonic;
• hypabyssal;
• volcanic.

Subgroups can be divided into:

• sour;
• medium;
• basic;
• ultrabasic.

It is almost impossible to compile a complete list of rocks, considering all the species that exist on Earth, there are so many of them. Within the framework of this article, we will attempt to structure information about the most interesting and frequently encountered types.

Metamorphic rocks: list

Those are formed under the influence of those inherent in the earth's crust. Since transformations occur when substances are in the solid phase, they are visually invisible. During the transition, the structure, texture, and composition of the original rock change. For such changes to occur, a successful combination is necessary:

• heating;
• pressure;
• influence of gases, solutions.

There is a metamorphism:

• regional;
• contact;
• hydrothermal;
• pneumatolytic;
• dynamometamorphism.

Amphibolites

These minerals are also formed by plagioclase. The first is classified as ribbon silicate. Visually, amphibolites are shales or arrays of colors from dark green to black. The color depends on the ratio in which the dark-colored components are present in the composition of the mineral. Minor minerals of this group:

• Garnet;
• magnetite;
• titanite;
• zoisite.

gneisses

In its structure, gneiss is exceptionally close to granite. It is far from always possible to visually distinguish these two minerals from each other, since gneiss copies granite and approaches it in physical parameters. But the price of gneiss is significantly lower.

Gneisses are widely available and therefore applicable in construction. Minerals are diverse and aesthetic. The density is high, so stone can be used as concrete aggregate. With a small porosity and a low ability to absorb water, gneisses have an increased resistance to freezing. Since weathering is also small, it is allowed to use the mineral as a facing.

Slates

When compiling a list of rocks, shales must be mentioned among the metamorphic ones. There are such types as:

• clay;
• crystalline;
• talc;
• chlorite.

Due to the unusual structure and aesthetics of this stone, in recent years slate has become an indispensable decorative material used in construction.

Slates are pretty large group which is made up of rocks. List of species names actively used by mankind for various purposes (mainly in construction, repair, reconstruction):

• siltstone;
• goldite;
• serpentinite;
• gneissic;
• and phyllite shales.

Quartzite

This stone is known for its durability, as it is formed by quartz with the addition of impurities. Quartzite is formed from sandstone when the original elements of the mineral are replaced by quartz during regional metamorphism.

In nature, quartzite is found in a continuous layer. Common impurities:

• hematite;
• granite;
• silicon;
• magnetite;
• mica.

The richest deposits are found in:

• India;
• Russia;
• Canada.

The main features of the mineral:

• resistance to frost, moisture, temperatures;
• strength;
• safety, environmental cleanliness;
• durability;
• resistance to alkalis, acids.

Phyllit

Not the last place in the list of rocks belongs to phyllites. They occupy an intermediate position between argillaceous and mica shales. The material is dense and fine-grained. At the same time, the stones are obviously crystalline, they are characterized by pronounced schistosity.

Phyllites have a silky sheen. Colors - black, shades of gray. Minerals break into thin slabs. Phyllites are composed of:

• mica;
• sericite.

There may be grains, crystals:

• albite;
• andalusite;
• grenade;
• quartz.

Phyllite deposits are rich in France, England and the USA.

Sedimentary rocks: list

Minerals of this group are located mainly on the surface of the planet. For formation, the following conditions must be met:

• low temperatures;
• precipitation.

There are three genetic subspecies:

• clastic, which are rough stones formed during the destruction of the rock;
• clay, the origin of which is associated with the transformation of minerals of the "silicate" and "aluminosilicate" groups;
• biochemo-, chemo-, organogenic. Such are formed in the processes of deposition in the presence of appropriate solutions. Microscopic and not only organisms, substances of organic origin also take an active part in this. The role of waste products is important.

From chemogenic emit:

• halide;
• sulfate.

List of rocks of this subgroup:

• gypsum;
• anhydrites;
• sylvinite;
• rock salt;
• carnallite.

The most important sedimentary rocks are:

• Dolomite, similar to dense limestone.
• Limestone, consisting of potassium carbonate with an admixture of the same magnesium and a number of inclusions. The parameters of the mineral vary, determined by the composition and structure, as well as the texture of the mineral. A key feature is increased compressive strength.
• Sandstone formed by mineral grains bound together by substances of natural origin. The strength of the stone depends on the impurities and what kind of substance has become a binder.

Volcanic rocks

Volcanic rocks must be mentioned. A list of those is created, including here the minerals formed during this. At the same time, they distinguish:

• poured out;
• clastic;
• volcanic.

• andesite;
• basalt;
• diabase;
• liparitis;
• trachyte.

Pyroclastic, that is, detrital, include:

• breccias;
• tuffs.

An almost complete alphabetical list of volcanic type rocks:

• anorthosite;
• granite;
• gabbro;
• diorite;
• dunit;
• comatite;
• latite;
• monzonite;
• obsidian;
• pegmatite;
• peridotite;
• perlite;
• pumice;
• rhyolite;
• syenite;
• tonalit;
• felsite;
• slag.

organic rocks

Organic rocks are formed from the remains of living beings, the list of which rightfully begins with the most significant substance - chalk. These rocks belong to the sedimentary group already discussed above, and are important not only in terms of applicability to solving various human problems, but also as a rich archaeological material.

The most important subspecies of this type of rock is chalk. It is widely known and actively used in everyday life: it is they who write on the boards in schools.

The chalk is formed by calcite, from which the shells of coccolithophorid algae that lived in ancient seas previously consisted. These were microscopic organisms that inhabited our planet in abundance about a hundred million years ago. At that time, algae could freely swim across vast areas of the warm sea. Dying, microscopic organisms fell to the bottom, forming a dense layer. Some areas are rich in deposits of such sediments, with a thickness of a hundred meters or more. The most famous chalk hills are:

• Volga;
• French;
• English.

Studying Cretaceous rocks, scientists find traces in them:

• sea ​​urchins;
• shellfish;
• sponges.

As a rule, these inclusions are only a few percent of the total explored chalk, so such components do not affect the parameters of the rock. Having studied the Cretaceous deposits, the geologist obtains information about:

• breed age;
• thicker than the water that was here before;
• special conditions that previously existed in the study area.

Igneous rocks

Magmatism is commonly understood as a set of phenomena caused by magma and its activity. Magma is a silicate melt that is present in nature in a liquid form close to fire. Magma contains a high percentage of volatile elements. In some cases, there are types:

• non-silicate;
• low silicate.

When magma cools and crystallizes, igneous rocks form. They are also called igneous.

Allocate breeds:

• intrusive;
• effective.

The former were formed at great depths, and the latter - during the eruption, that is, already directly on the surface of the planet.

Often, magma contains various rocks that have melted and mixed with the silicate mass. This is provoked:

• an increase in temperature in the thickness of the earth;
• pressurized pressure;
• a combination of factors.

The classic version of the igneous rock is granite. Already its very name in Latin - "fire", reflects the fact that the breed in its original state was exceptionally hot. Granite is highly valued not only for its technical parameters (this material is incredibly durable), but also because of the beauty due to crystalline inclusions.

Classification of sedimentary clastic (terrigenous) rocks

Lecture topic: Introductory. Geology, content, tasks, sections and methods. Short story development of petroleum geology.

Abstract of lectures

Geology is the science of the Earth (from the Greek "geo" - Earth, "logos" - knowledge, science). The Earth is a complexly constructed body, occupying a certain position in the Universe, characterized by a certain physical state and chemical composition, and continuously evolving over time. Because of this, besides geology, other sciences are also engaged in the study of the Earth - geophysics, geochemistry. Geophysics studies the internal structure of the Earth, the physical state of its interior, its physical fields - gravitational (gravitational field), magnetic, thermal, electrical. The task of geochemistry includes the study of the chemical composition of the Earth and its individual shells, the fate of atoms of chemical elements and their isotopes. The subject of geology research is mainly the upper stone shell of the Earth - the earth's crust, or rather, the lithosphere, which, in addition to the crust, covers the upper part of the mantle. Geology aims to restore and explain the history of the development of the Earth, based on the study of its material composition, structure and processes that change the internal state of the globe and the earth's surface.

Geology studies the composition, structure and development of the Earth under the influence of processes occurring in its external and internal spheres, as well as the patterns and processes of the formation of the earth's crust, its constituent minerals, rocks, minerals and the history of the development of life on Earth. In general, geological knowledge is a necessary and important link in the scientific worldview.

The significance of geological science for human economic activity has steadily increased as new types of minerals are involved in this activity - from coal to uranium ore and rare elements. Another major task of applied geology is the study of the geological conditions of places intended for the construction of various engineering structures - hydroelectric power plants, nuclear power plants, canals, etc. in order to ensure their sustainability. Another important role of geology is the prevention and consideration of the possible consequences of natural catastrophic events - earthquakes, volcanic eruptions, landslides, etc. Relatively recently, mankind has realized the need to preserve the natural environment and assess the direction of its natural change and ecology - the science of the environment has taken a prominent place among other sciences, and a section related to the geological component of this environment has taken shape in its composition - geoecology.

The practical significance of geology primarily lies in the development of methods for discovering minerals. Among the minerals, there are ore or metal (various metals are mined from them), non-metallic (from which phosphorus, potassium are mined for fertilizers, rock salt, sulfur and others), building materials, precious (diamond, ruby, sapphire and others), semi-precious (amethyst, jasper, malachite and others) stones, combustible (coal, oil, combustible gas).

To date, geology has developed reliable criteria for predicting various minerals, primarily such as oil, natural gas, coal, ores of ferrous and non-ferrous metals. Thus, modern geological science serves as a theoretical basis for prospecting, exploration and development of all types of minerals. Modern industry is largely based on the use of the Earth's mineral resources - oil, gas, coal, ferrous and non-ferrous metal ores, building materials, groundwater, salts, etc. Geology plays a particularly important role in the search for and exploration of deposits of energy and chemical raw materials - oil and gas.

Today, geology is a combination of many geological disciplines that emerged from it as a result of the in-depth development of certain branches of geological knowledge and the improvement of geological research methods. In this regard, several main sections of geology can be distinguished:

1) sciences that study the material composition of the Earth (geochemical cycle); 2) sciences that study the processes occurring in the depths of the Earth and on its surface (dynamic geology); 3) sciences that study the history of the Earth (historical geology); 4) sciences aimed at practical use bowels of the Earth (applied geology).

The geochemical cycle includes crystallography, mineralogy, petrology, lithology, proper geochemistry. Crystallography - the science of crystals, their external form and internal structure. Mineralogy - the science of minerals, natural chemical compounds that make up rocks or occur separately. Mineralogy considers the chemical composition of minerals, their structural features, physical properties, conditions of occurrence, relationships and origin. Petrology - the science of rocks, studies the mineralogical and chemical composition of rocks, their properties, structure, conditions of occurrence, and also studies their origin and changes experienced by rocks under the influence of various factors. A special class of rocks - sedimentary rocks - is the subject of study lithology (Greek "lithos" - stone). Geochemistry - the science of chemical composition Earth, studies chemical elements, establishes patterns of distribution, combination and movement of individual chemical elements in the bowels of the Earth and on its surface. Geochemistry operates with atoms, mineralogy studies combinations of atoms (minerals), petrology - combinations of minerals (rocks).

Dynamic geology studies the geological processes occurring in the bowels of the lithosphere and on its surface. Depending on the source of energy, they are divided into exogenous (born from external causes) and endogenous (born from internal causes). Exogenous processes proceed under the action of solar energy in combination with gravitational (gravity); endogenous - under the influence of internal energy, internal heat of the Earth, also in combination with gravitational energy.

Historical geology studies the history of the earth's crust in connection with the development of the earth as a planet as a whole. It, in turn, is subdivided into a number of sciences. Stratigraphy is the study of the layers of sedimentary rocks and the sequence of their occurrence. Paleontology is the science of the fossil remains of organisms. The study of the remains of ancient, extinct organisms buried in the layers, a set of which was characteristic of certain epochs of the Earth's history, helps in establishing the relative age of sedimentary rocks.

The next branch of geology closest to applied geology is regional geology. It deals with the description of the geological structure - the age sequence of rocks, the structural forms they form, as well as the history of the development of individual sections (regions) of the earth's crust, from small to very large - continents and oceans. The structure of the earth's crust is usually depicted on geological maps of various scales, which reflect the distribution of rocks of various types, compositions and ages on the Earth's surface. Geological maps and their derivative varieties - tectonic and other maps - serve as the basis for the search and exploration of minerals.

The main method of geological research is the study of natural outcrops (outcrops) of rocks, starting with a description of their composition, type, conditions of occurrence and relationships. For a more accurate determination of the composition and type of minerals, rocks, minerals, samples (samples) are taken and subjected to laboratory analysis - chemical, mineralogical and others. In sedimentary rocks, searches are being made for organic remains, by which it is possible to determine the relative age of the rock by the paleontological method, and various methods are widely used. physical methods determining the age of rocks. To study rocks occurring at great depths, data from boreholes, mines and other mine workings are used. Geophysical and geochemical methods are used to study the deep parts of the globe. Geophysical methods are based on the fact that rocks of different composition have different physical properties. Unlike most natural sciences, which make extensive use of laboratory experience in geology, the experimental method is of limited value. The main difficulty lies in the incommensurability of the time scale of geological processes with the duration human life. However. At present, work is being successfully carried out on the application of the experiment (physical modeling) in various fields of research. So, for example, in tectonics - reproduction of deformation of rocks, mineralogy - synthesis of minerals, including diamond, petrology - melting and synthesis of rocks, in engineering geology and other branches of geological science.

Observations are of primary importance in geological research. In this case, various methods developed on the basis of other sciences are used. The stage of observation and collection of materials is followed by the stage of generalizations and conclusions, which is associated with the establishment of patterns of phenomena and the construction of scientific hypotheses or theories. Further verification of the obtained conclusions is necessary. In geological research, it consists in repeated observation, comparison of a wider range of facts and confirmation by experimental data. One of the most important methods of geological generalizations concerning the nature of geological processes is the method of actualism. The most concise formulation was given by the famous British geologist of the 19th century C. Lyell: "The present is the key to knowing the past." The essence of the method lies in understanding the past by studying modern geological processes and comparing their results with the results of geological processes of the distant past can point the right way to understanding the latter. The successful solution of the theoretical problems of geology is connected with the solution of one of the important practical problems - the forecast of the search for mineral resources necessary for the national economy.

Oil and gas geology studies the origin, conditions of migration and formation of accumulations and the history of these minerals, and also studies oil and gas deposits and deposits in their natural state and in the process of development to determine their significance and rational use of the subsoil.

The purpose of the geological service is to obtain information about the material composition of rocks, their age and structure, the nature of saturation with fluids, and also about physical and chemical properties oils, gases, underground waters.

Oil, natural gas and their derivatives - combustible minerals - natural formations, which can be a source of thermal energy. Combustible minerals serve as the most valuable fuel, and in order for a substance to be such, it must have a sufficiently high calorific value, be widespread, its combustion products must be volatile so as not to impede the combustion process and not be harmful and poisonous to people.

Fossil fuels are also valuable raw materials for the chemical industry, especially oil.

The oil industry in the world is about 150 years old. Its origin in different countries of the world occurred almost simultaneously.

In 1859, the American entrepreneur Drake (Pennsylvania) received an industrial flow of oil from a well he drilled, which marked the beginning of the US oil industry. Five years later (1864), a retired colonel Novosiltsev in Russia, from a well drilled on the Kudako River (the left tributary of the Kuban River, the northwestern slope of the Caucasus), received a fountain of oil. This fact testifies to the beginning of the oil industry in Russia. In the region of Baku (Azerbaijan), the first industrial oil was obtained in 1871 from a well drilled by the entrepreneur Mirzoev. An oil gusher with a flow rate of 32 t/day blew here from a depth of only 40-45 meters.

The first oil of Kazakhstan was obtained in 1899 in the Karashungul area in well 7 from a depth of only 40 m from Paleogene deposits. The daily flow rate of the well reached 25 tons/day. But, according to many geologists, in fact, the oil industry of Kazakhstan takes its start from Dossor, when on April 29, 1911, well 3 was drilled in the Dossor tract on the salt dome structure of the same name (90 km northeast of Atyrau), from which (interval 225-226 meters, Middle Jurassic) hit a powerful gusher of oil, throwing out over the next few days 16,000 tons of high-quality sweet, oily oil. This date is considered by many oilmen as the actual beginning of the oil industry in Kazakhstan for the following reasons. Karashungul oil migrated to the Paleogene deposits from the underlying Lower Cretaceous and Jurassic deposits, so its reserves turned out to be very modest and it was never used on a large scale. But Dossor oil immediately, in the same 1911, began to be produced in relatively large volumes and intensively used in the economy.

With the birth of the world's oil industry, the geology of oil and gas finally took shape as a separate applied science of the geological cycle. With the development of the oil industry, oil production is growing rapidly. Thus, in Russia in the entire history of the existence of the oil industry (starting from 1864) more than 4 billion tons of oil have been produced.

If the first billion tons took 90 years, then the second took seven, the third only four and a half years, and the fourth less than two years. The depths of oil wells are also growing rapidly from 50-100 meters to 5-7 km at present.

Petroleum geology from the first days of its formation took shape as an independent science of the geological cycle and considers a wide range of issues. It is based on the sciences of geological, chemical, physical and biological cycles.

Oil and gas originate and form accumulations mainly in the rocks of the sedimentary layer. Very rarely, oil and gas accumulate in the granite-gneiss layer of the earth's crust. Consequently, their further conservation and preservation for a long geological time is associated with the earth's crust, the development of which is subject to general geological laws.

Oil, to a lesser extent, and natural hydrocarbon gas are complex chemical compounds, therefore, in order to determine their composition and structure, it is necessary to know and be able to apply the laws of general and organic chemistry (the science of the chemical cycle).

Petroleum science investigates a specific, liquid and gaseous mineral that is able to move (migrate) in the earth's crust. Consequently, when studying the conditions for the formation of accumulations of hydrocarbons (HC) and the patterns of their occurrence, as well as their physical properties, a petroleum geologist uses physical laws (sciences of the physical cycle).

The vast majority of geologists adhere to the organic theory of oil and gas formation, therefore biology and biochemistry serve as a support not only in solving the problem of the origin of hydrocarbons, the formation of their accumulations, but also their destruction, including biologically (the science of the biological cycle).

Petroleum geology provides answers to two main groups of questions: how oil and gas were formed and what they are; where to look for these valuable minerals. In other words, petroleum geology provides answers to next questions: how and where oil and gas lie in the bowels of the earth's crust, how millions of years of their accumulation are formed and preserved, what are the patterns of their distribution over the area of ​​the globe, how oil and gas arose in nature in such large volumes.

The main objective of the course is to study the forms of accumulations of oil and gas in the subsoil (types of deposits, deposits), the patterns of their location, the conditions for their occurrence, transformation and destruction (generation, accumulation, conservation).

Basic literature: 4, 5,

Further Reading 14

Test questions:

1. What is the date of the beginning of the oil industry in the world.

2. What is the date of the beginning of the oil industry in Kazakhstan

3. On what sciences is petroleum geology based?

4. What questions does the geology of oil and gas study

2. Topic of the lecture: Structure and composition of the Earth. Earth in outer space. The shape and size of the earth. The internal structure of the Earth. Chemical and mineral composition of the Earth's interior. Physical fields of the Earth. The structure and composition of the earth's crust. Material composition of the earth's crust. Minerals. Rocks.

The earth is one of the countless celestial bodies scattered in the boundless space of the Universe. A general idea of ​​the position of the Earth in world space and its relationship with other cosmic bodies is also necessary for the course of geology, since many processes occurring on the surface and in the deep interior of the globe are closely related to the influence external environment surrounding our planet. The knowledge of the Universe, the study of the state of various bodies and the processes occurring on them shed light on the problems of the origin of the Earth and the early stages of its development. The Universe is the whole world, boundless in time and space and infinitely diverse in the forms that matter takes in its development. The universe consists of countless bodies, very different in structure and size. The following main forms of cosmic bodies are distinguished: stars, planets, interstellar matter. Stars are large active cosmic bodies. The radius of large stars can reach a billion kilometers, and the temperature even on the surface can reach many tens of thousands of degrees. Planets are relatively small cosmic bodies, usually cold and usually satellites of stars. The space between space bodies is filled with interstellar matter (gases, dust). Space bodies are grouped into systems within which they are interconnected by gravitational forces. The simplest system - the Earth with its satellite Moon, forms a system of a higher order - the Solar System. An even more complex structure is characterized by clusters of cosmic bodies of a higher order - galaxies. The galaxy is an example of such a system. Milky Way, which includes the solar system. In shape, our galaxy resembles a biconvex lens, and in plan it is a bright cluster of stars in the core with spiraling star streams.

Structure solar system. Our solar system includes, in addition to the central luminary - the Sun, nine planets, their satellites, asteroids and comets. The Sun is a star, a hot plasma ball, a typical "yellow dwarf", which is at the middle stage of stellar evolution. The Sun is located within one of the spiral arms of our Galaxy and revolves around the center of the Galaxies with a period of about 200 million years. The temperature inside the Sun reaches several million years. The source of the Sun's energy is the thermonuclear conversion of hydrogen into helium. Spectral study of the Sun made it possible to identify in its composition 70 elements known on Earth. The sun consists of 70% hydrogen, 27% helium, and about 3% of the rest of the elements. The Sun contains 99.886% of the entire mass of the solar system. The sun has a huge influence on the Earth, on earthly life, its geological development. Our planet - the Earth is 149,600,000 km away from the Sun. The planets around the Sun are arranged in the following order: four inner - Mercury, Venus, Earth and Mars (terrestrial planets) and five outer - Jupiter, Saturn, Uranus, Neptune, Pluto. Between Mars and Jupiter is an asteroid belt - several thousand small solid bodies. For geologists, four inner planets are of interest, which are characterized by small size, high density, and low mass. These planets are closest in size, composition and internal structure to our Earth. According to modern ideas, the bodies of the Solar System were formed from the initially cold cosmic solid and gaseous matter by compaction and thickening until the formation of the Sun from the central part. From the particles of the surrounding gas-dust matter, as a result of accretion, planets were formed that revolve in orbits around the Sun.

General characteristics of the Earth. The shape and size of the earth. Under the figure, or form of the Earth, understand the shape of its solid body, formed by the surface continents and the bottom of the seas and oceans Geodetic measurements have shown that the simplified form of the Earth is approaching an ellipsoid of revolution (spheroid). The actual shape of the Earth is more complex, as there are many irregularities on its surface. The closest to the modern figure of the Earth is the figure, in relation to the surface of which the force of gravity is everywhere directed perpendicularly. It is called the geoid, which literally means "earth-like". The surface of the geoid in the seas and oceans corresponds to the surface of the water, and on the continents it corresponds to the water level in imaginary channels that cross all the continents and communicate with the World Ocean. The surface of the geoid approaches the surface of the spheroid, deviating from it by about 100 m, on the continents it slightly rises in relation to the surface of the spheroid, and in the oceans it decreases. Measurements of the dimensions of the Earth showed the following: equatorial radius - 6378.2 km; polar radius - 6356.8 km; the average radius of the Earth is 6371 km; polar compression - 1/298; surface area - 510 million square kilometers; the volume of the Earth-1, 083 billion. km cube; mass of the Earth-6*10 21 t; average density-5, 52 g/cm 3

Physical properties of the Earth. The earth has certain physical properties. As a result of their study, common features structure of the Earth and it is possible to establish the presence of minerals in its bowels. The physical properties of the Earth include gravity, density, pressure, magnetic, thermal, elastic, electrical and other properties. Gravity, density, pressure. The force of gravity and centrifugal force are constantly acting on the Earth. The resultant of these forces determines the force of gravity. The force of gravity varies both horizontally, increasing from the equator to the poles, and vertically, decreasing with height. Due to the uneven distribution of matter in the earth's crust, the actual value of gravity deviates from normal. These deviations were called gravity anomalies. They are either positive (in the presence of denser rocks) or negative (in the presence of less dense rocks). Gravity anomalies are studied using gravimeters. The branch of applied geophysics that studies gravity anomalies in order to identify minerals or favorable geological structures in the depths is called gravity exploration. According to gravimetric data, the average density of the Earth is 5.52 g / cm 3. The density of the rocks that make up the earth's crust is from 2.0 to 3.0 g / cm 3. The average density of the earth's crust is 2.8 g / cm 3. The difference between the average density of the Earth and the Earth's crust indicates a denser state of matter in the inner parts of the Earth, reaching about 12.0 g/cm 3 in the core. Simultaneously with the increase in density towards the center of the Earth, the pressure also increases. In the center of the Earth, the pressure reaches 3.5 million atm. Earth magnetism. The earth is a giant magnet with a force field around it. The Earth's magnetic poles are currently located near the geographic poles, but do not coincide with them. Distinguish between magnetic declination and magnetic inclination. Magnetic declination is the angle of deviation of the magnetic needle of the compass from the geographic meridian. Declension can be western and eastern. Magnetic inclination is determined by the angle of the magnetic needle to the horizon. The greatest inclination is observed in the region of the magnetic poles. The influence of rocks containing ferromagnetic minerals (magnetite and some others) is superimposed on the general background of the magnetic field, as a result of which magnetic anomalies appear on the Earth's surface. Magnetic prospecting is engaged in the identification of such anomalies in order to search for iron ores. Studies have shown that rocks containing ferromagnetic minerals have remanent magnetization that preserves the direction of the magnetic field of time and the place of their formation. Paleomagnetic data are used to restore the features of the magnetic field of ancient epochs, as well as to solve problems of geochronology, stratigraphy, and paleogeography. They had a great influence on the development of the theory of lithospheric plate tectonics.

Heat of the Earth. The thermal regime of the Earth is caused by two sources: heat received from the Sun; heat released from the Earth's interior. The Sun is the main source of heat on the Earth's surface. Heating by the Sun extends to an insignificant depth not exceeding 30 m. At a certain depth from the surface there is a belt of constant temperature equal to average annual temperature this locality. In the vicinity of Moscow, at a depth of 20 m from the surface, a constant temperature of +4.2 0 is observed. Below the belt of constant temperature, an increase in temperature with depth associated with the heat flow coming from the inner parts of the Earth is established. The increase in temperature in degrees Celsius per unit of depth is called the geothermal gradient, and the depth interval in meters at which the temperature rises by 1 0 is called the geothermal step. The value of the geothermal step varies widely: in the Caucasus 12 m, in the Emba region 33 m, in the Karaganda basin 62 m, in Kamchatka 2-3 m. It is believed that the geothermal stage persists to a depth of 20 km. Below, the rise in temperature slows down. According to scientists, at a depth of 100 km, the temperature apparently reaches 1300 0 C. At a depth of 400 km - 1700 0 C, 2900 km - 3500 0 C. The sources of the Earth's internal heat are considered to be the radioactive decay of elements, during which a huge amount of heat is released, the energy of gravitational differentiation of matter , as well as residual heat from the formation of the planet.

The structure of the earth. The earth is characterized by a shell structure. The shells of the Earth, or the geosphere, differ in composition, physical properties, state of matter and are divided into external, accessible for direct study, and internal, studied mainly by indirect methods (geological, geophysical, geochemical). The outer spheres of the Earth - the atmosphere, hydrosphere and biosphere are a characteristic feature of the structure of our planet and play an important role in the formation and development of the earth's crust. Atmosphere- the gaseous shell of the Earth, plays one of the main roles in the development of life on Earth and determines the intensity of geological processes on the surface of the planet. The air shell of our planet, the total mass of which is estimated at 5.3 * 10 15 m, is a mixture of various gases: nitrogen (78.09%), oxygen (20.95%), argon (0.93%). In addition, there is carbon dioxide(0.03%), hydrogen, helium, neon and other gases, as well as water vapor (up to 4%), particles of volcanic, aeolian and cosmic dust. Air oxygen provides the processes of oxidation of various substances, as well as the respiration of organisms. There is ozone in the atmosphere at an altitude of 20-30 km. The presence of ozone protects the Earth from the damaging effects of ultraviolet and other radiation from the Sun. Carbon dioxide and water vapor act as a temperature regulator, as it condenses the heat received by the Earth. Carbon dioxide enters the air as a result of the decomposition of organisms and their respiration, as well as during volcanic processes, but is consumed to feed plants. air masses atmospheres are in constant motion under the influence of uneven heating of the Earth's surface in different latitudes, uneven heating of continents and oceans. Air flows carry moisture, solid particles - dust, significantly affect the temperature of various regions of the Earth. The atmosphere is divided into five main layers: troposphere, stratosphere, mesosphere, ionosphere and exosphere. For geology, the most interesting is the troposphere, which is in direct contact with the earth's surface and exerts a significant influence on it. Troposphere characterized by high density, the constant presence of water vapor, carbon dioxide and dust, a gradual decrease in temperature with height and the existence of vertical and horizontal air circulation.

Hydrosphere- a discontinuous shell of the Earth, including the waters of the oceans, seas, lakes and rivers, groundwater and water collected in the form of eternal snow and ice. The main part of the hydrosphere is the World Ocean, which unites all the oceans, marginal and associated inland seas. The amount of oceanic land water is 4 million km 3, continental ice is about 22 million km 3, groundwater is 196 million km 3. The hydrosphere occupies 70.8% of the earth's surface (361 million km 2). The average depth is 3750 m, the maximum depth is confined to the Mariana Trench (11022 m). Ocean and sea waters characterized by a certain chemical composition and salinity. The normal salinity of the waters of the World Ocean is 3.5% (35 g of salts per 1 liter of water). The waters of the ocean contain almost all known chemical elements. It is calculated that the total amount of salts dissolved in the water of the World Ocean is 5*10 16 m. Carbonates, silica are widely extracted from water by marine organisms for the construction of skeletal parts. Therefore, the salt composition of ocean waters differs sharply from the composition of river waters. AT ocean waters chlorides predominate (88.7%) - NaCl, MgCl 2 and sulfates (10.8%), and in river waters carbonates (60.1%) - CaCO 3 and sulfates (9.9%). In addition to salts, some gases are also dissolved in water - mainly nitrogen, oxygen, carbon dioxide. The waters of the hydrosphere, together with the substances dissolved in it, are actively involved in chemical reactions occurring in the hydrosphere, as well as in interaction with the atmosphere, the earth's crust and the biosphere. The hydrosphere, like the atmosphere, is the active force and medium of exogenous geological processes. The oceans play a huge role in the life of both the entire planet and humanity. In the ocean and in its bowels there are huge reserves of mineral resources, which are increasingly attracted for the needs of mankind (oil, chemical raw materials, etc.). The waters of the oceans are polluted by oil and oil products, radioactive and household waste. This circumstance is acquiring menacing proportions and requires an urgent solution.

Biosphere. The biosphere is the area of ​​distribution of life on Earth. The modern biosphere includes the entire hydrosphere, the upper part of the atmosphere (troposphere). Below the soil layer, living organisms are found in deep cracks, underground waters, sometimes in oil-bearing layers at a depth of thousands of meters. The composition of living organisms includes at least 60 elements, and the main ones are C, O, H, S, P, K, Fe and some others. The living mass of the biosphere in terms of dry matter is about 10 15 tons. The bulk of the living matter is concentrated in green plants that can accumulate solar energy through photosynthesis. From a chemical point of view, photosynthesis is a redox reaction CO 2 + H 2 O-> CH 2 O + O 2, as a result of which, due to the absorption of carbon dioxide and water, organic matter is synthesized and free oxygen is released. The biosphere plays an important role in the energy of the Earth. Over millions of years, the biosphere has accumulated colossal reserves of energy in the depths - in the thickness of coal, oil, accumulations of combustible gas. Organisms are important rock-forming earth's crust.

Internal structure of the Earth. Study of deep structure Earth is one of the main tasks of modern geology. Only the uppermost (down to depths of 12-15 km) horizons of the earth's crust, which come to the surface or are opened by mines and boreholes, are accessible to direct observation.

Ideas about the structure of the deeper zones of the Earth are based mainly on these complexes of geophysical methods. Of these, the seismic (Greek "seisma" - shaking) method is of particular importance, based on recording the propagation velocity in the Earth's body of waves caused by earthquakes or artificial explosions. In earthquake sources, longitudinal seismic waves arise, which are considered as a reaction of the medium to changes in volume, and transverse waves, which are a reaction of the medium to changes in shape and therefore propagate only in solids. Currently, the available data confirm the spherically - symmetrical structure of the Earth's interior. Back in 1897, E. Wiechert, a professor at the University of Göttingen, suggested the shell structure of the Earth, which consists of an iron core, a stone mantle, and the earth's crust. In 1910, the Yugoslav geophysicist A. Mohorovichic, studying the propagation of seismic waves during an earthquake near the city of Zagreb, established the interface between the crust and the mantle at a depth of 50 km. In the future, this surface was identified at various depths, but they were always clearly traced. She was given the name "Mohorovicic surface", or Moho (M). In 1914, the German geophysicist B. Guttenberg established the boundary between the core and the mantle at a depth of 2900 km. It is called the Wiechert-Guttenberg surface. Danish scientist I. Leman in 1936. substantiated the existence of the inner core of the Earth with a radius of 1250 km. The whole complex of modern geological and geophysical data confirms the idea of ​​a shell structure of the Earth. To correctly understand the main features of this structure, geophysicists build special models. Well-known geophysicist V.N. Zharkov characterizes the model of the Earth: it is “like a section of our planet, which shows how its most important parameters change with depth, such as density, pressure, acceleration of gravity, seismic wave velocities, temperature, electrical conductivity, and others” (Zharkov, 1983, p. 153). The most common is the Bullen-Guttenberg model.

The Earth's crust is the hard upper shell of the Earth. Its thickness varies from 5-12 km under the waters of the oceans, to 30-40 km in flat areas and up to 50-750 km in mountainous areas. The Earth's mantle extends to a depth of 2900 km. It is subdivided into two parts: the upper to a depth of 670 km and the lower to a depth of 2900 km. The seismic method established a layer in the upper mantle in which a decrease in the speed of seismic waves, especially transverse ones, and an increase in electrical conductivity are observed, which indicates a state of matter that differs from the above and below layers. The features of this layer, called the asthenosphere (Greek astyanos-weak) are explained by its melting in the range of 1-2 to 10%, which occurs as a result of a faster increase in temperature with depth than an increase in pressure. The asthenospheric layer is located closest to the surface under the oceans, from 10-20 km to 80-200 km, from 80 to 400 km under the continents. The earth's crust and part of the upper mantle above the asthenosphere is called the lithosphere. The lithosphere is cold, so it is rigid and can withstand heavy loads. The lower mantle is characterized by a further increase in the density of matter and a smooth increase in the velocity of seismic waves. The core occupies the central part of the Earth. It consists of an outer core, a transitional shell and an inner core. The outer core consists of a substance in a molten-liquid state. The inner core occupies the core of our planet. Within the inner core, the velocities of longitudinal and transverse waves increase, which indicates the solid state of matter. The inner core consists of an iron-nickel alloy.

Composition and structure of the earth's crust. The most reliable information is available on the chemical composition of the uppermost part of the earth's crust, accessible for direct analysis (down to a depth of 16-20 km). The first figures on the chemical composition of the earth's crust were published in 1889 by the American scientist F. Clark. Subsequently, A.E. Fersman suggested calling the percentage of an element in the earth's crust the clarke of this element. According to A.B. Ronov and A.A. Yaroshevsky (1976), eight elements (in weight%) are the most common in the composition of the earth's crust, making up more than 98% in total: oxygen - 46.50; silicon-25.70; aluminum-7.65; iron-6.24; calcium-5.79; magnesium-3.23; sodium-1.81; potassium-1.34. According to the features of the geological structure, geophysical characteristics and composition, the earth's crust is divided into three main types: continental, oceanic and intermediate. The continental layer consists of a sedimentary layer 20-25 km thick, granite (granite-metamorphic) layer up to 30 km thick and basalt layer up to 40 km thick. The oceanic crust consists of the first sedimentary layer up to 1 km thick, the second basalt layer 1.5-2.0 km thick and the third gabbro-serpentinite layer 5-6 km thick. The substance of the earth's crust consists of minerals and rocks. Rocks are composed of minerals or products of their destruction. Rocks containing useful components and individual minerals, the extraction of which is economically feasible, are called minerals.

Main literature: 1

Test questions:

1 The origin of the solar system.

2 The shape and size of the Earth.

3 Physical fields of the Earth.

4 The internal structure of the Earth.

5 The structure and composition of the earth's crust.

3 Lecture topic: Rocks as a container for oil and gas. A rock is a natural, most often, solid body, consisting of one (limestone, anhydrite) or several minerals (polymictic sandstone, granite). In other words, it is a natural natural association of minerals. All rocks by origin (genesis) are divided into three large classes: igneous, metamorphic and sedimentary.

Igneous rocks were formed as a result of the introduction of magma (silicate melt) into the earth's crust and the solidification of the latter in it (intrusive igneous rocks) or the outpouring of lava (silicate melt) to the bottom of the seas, oceans or the earth's surface (effusive igneous rocks). Both lava and magma are originally silicate melts of the inner spheres of the Earth. Magma, having penetrated into the earth's crust, solidifies in it unchanged, and lava, pouring out onto the surface of the Earth or to the bottom of the seas and oceans, loses the gases dissolved in it, water vapor and some other components. Because of this, intrusive igneous rocks differ sharply in composition, structure, and texture from effusive ones. Granite (an intrusive rock) and basalt (an effusive rock) are examples of the most common igneous rocks.

Metamorphic rocks were formed as a result of a radical transformation (metamorphism) of all other pre-existing rocks under the influence of high temperatures, pressures, and often with the addition or removal of individual chemical elements from them. Typical representatives of metamorphic rocks are marble (formed from limestone), various shales and gneisses (formed from clayey sedimentary rocks).

Sedimentary rocks were formed due to the destruction of other rocks that previously formed the earth's surface and the precipitation of these mineral substances mainly in an aqueous, less often air environment as a result of the manifestation of exogenous (surface) geological processes. Sedimentary rocks according to the method (conditions) of their formation are divided into three groups: sedimentary clastic (terrigenous), organogenic and chemogenic.

Sedimentary clastic (terrigenous) rocks are composed of fragments of pre-existing minerals and rocks (Table 1). Organogenic rocks consist of the remains (skeletons) of living organisms and their metabolic products (biological way of formation). Chemogenic sedimentary rocks were formed as a result of precipitation of chemical elements or minerals from aqueous solutions (Table 2). Typical representatives of sedimentary clastic rocks are sandstones and siltstones, sedimentary organogenic - various types of organogenic limestones, chalk, coal, oil shale, oil, sedimentary chemogenic - rock salt, gypsum, anhydrite. For a petroleum geologist, sedimentary rocks are dominant, since they not only contain 99.9% of the world's oil and gas reserves, but, according to the organic theory of the origin of oil and gas, are the generators of these hydrocarbons. Sedimentary rocks make up the upper sedimentary layer of the earth's crust, which is not distributed throughout the Earth's area, but only within the so-called plates that are part of the platforms - large stable sections of the earth's crust, intermountain depressions and foothill troughs. The thickness of sedimentary rocks varies widely from a few meters to 22-24 km in the center of the Caspian depression, located in Western Kazakhstan. The sedimentary layer in petroleum geology is usually called the sedimentary cover. Under the sedimentary cover is the lower structural floor, called the foundation. The foundation is composed of igneous and metamorphic rocks. The basement rocks contain only 0.1% of the world's oil and gas reserves. Oil and gas in the earth's crust fills the smallest and smallest pores, cracks, caverns of rock, just as water saturates a sponge. Therefore, for a rock to contain oil, gas, and water, it must be qualitatively different from fluid-free rocks, i.e. it must have pores, cracks or cavities, must be porous. At present, most often industrial accumulations of oil and gas contain sedimentary clastic (terrigenous) rocks, then carbonate rocks of organogenic genesis and, finally, chemogenic carbonates (oolitic and fractured limestones and marls). In the earth's crust, porous rocks containing oil and gas must be interbedded with qualitatively different rocks that do not contain fluids, but serve as insulators for oil and gas saturated bodies. Tables 1 and 2 show lithofacies of rocks containing oil and gas and serving as seals.