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. The champion of popularity among jewelry of biological nature is 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 of a 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 have a very conditional needle-like 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 fossilization is extremely long, 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 absorbed 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 looked at pearls in more detail in the article, and you can be sure that this stone of biological origin has been in favor with fashionistas for a reason 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 that originated from the resin of 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 closer look at the appearance of the gem! 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!

Natural stone is the oldest building material. Due to the complexity of processing, earlier it was used mainly for religious, defensive and palace structures, many of which are considered wonders of the world - the Egyptian pyramids, the Aztec pyramid, the Great Wall of China, the Taj Mahal mausoleum ... The current level of development of stone processing allows the use of stone in mass construction - both for exterior and interior decoration of buildings.
But each stone has its own characteristics, which are explained by its physical properties.

Origin and classification of rocks

Stone is one of the rocks. Rocks are called natural formations, consisting of individual minerals and their associations. The science of petrography deals with the study of the composition, origin and physical properties of rocks. According to her data, according to their origin, all breeds are divided into three main groups:

1. Igneous (primary)
2. Sedimentary (secondary)
3. Metamorphic (modified).

Igneous rocks formed directly from magma (molten mass of predominantly silicate composition), as a result of its cooling and solidification. Depending on the conditions of solidification, deep and erupted rocks are distinguished.
Deep ones arose as a result of the gradual cooling of magma at high pressure inside the earth's crust. Under these conditions, the constituents of the magma crystallized, due to which massive dense rocks with a fully crystalline structure were formed: granites, syenites, labradorites and gabbro.
The erupted rocks were formed as a result of a volcanic eruption of magma, which quickly cooled on the surface at low temperature and pressure. There was not enough time for the formation of crystals, therefore the rocks of this group have a latent or fine-crystalline structure and high porosity: porphyries, basalts, volcanic tuffs, ashes and pumice.

Sedimentary rocks are called secondary because they were formed as a result of the destruction of igneous rocks or from the waste products of plants and animals. One of the ways in which these rocks are formed is through chemical precipitation from the drying up of lakes and bays. As a result, various compounds precipitate, which eventually turn into travertine, dolomite. A common feature of these rocks is porosity, fracturing, and solubility in water.
Clastic sedimentary rocks include cemented deposits (sandstones, breccias, conglomerates) and loose (sands, clays, gravel and crushed stone). Cemented deposits formed from loose ones. For example, sandstone is made from quartz sand with lime cement, breccia is made from cemented crushed stone, and conglomerate is made from pebbles. Also known are rocks of organic origin - limestone and chalk. They are formed as a result of the vital activity of animals and plants.

metamorphic rocks formed by the transformation of igneous and sedimentary rocks into a new type of stone under the influence of high temperature, pressure and chemical processes. Among the metamorphic rocks, there are massive (granular), which include marble and quartzites, as well as schistous ones - gneisses and slates.

ROCKS PROPERTIES

decorative
An important property of rocks, which allows them to be used as a facing material, is decorativeness. This refers to the aesthetic appeal of natural stone, primarily its color and pattern.

Strength
If we talk about the use of natural stone in construction, then in this sense, one of its most important properties is strength, on which the wear resistance of the material depends. The stronger the stone, the longer it will last.
Depending on the hardness of the minerals that make up the rock and largely determine its properties, stones are conventionally divided into three groups:
durable- quartzites, granites, gabbro;
medium strength - marble, limestone, travertine;
low strength– loose limestones, tuffs.

Density
Density is the mass of a unit volume of a substance. The weight of the structure depends on this indicator: the higher the density of the stone, the heavier the structure. By density, stones are divided into light (density up to 2200 kg / m3) and heavy (density more than 2200 kg / m3). Density depends on the porosity of the rock and the minerals that make up its composition.

Porosity
The porosity of the stone, which is used as a facing material, is one of its most important characteristics. Water absorption and, accordingly, salt and acid resistance depend on porosity. And these are the main indicators that affect the durability of the material. In addition, the general porosity determines the strength, thermal conductivity, polishability, machinability, decorativeness of the stone and other quality characteristics. With an increase in the total porosity, the strength and volume of the stone decrease, its polishability deteriorates, but the weight of the product decreases and its ability to be processed improves.

Water absorption, salt, acid and frost resistance
Another important property of rocks associated with porosity is the water absorption index. The acid and salt resistance of the stone, as well as its frost resistance, depend on it and on the mineral composition of the material. Indeed, when freezing, the water in the pores increases in volume by 9%, creating powerful pressure. Water, penetrating into the pores of materials, leaves concentrated salt solutions on them after drying. From them, the growth of crystals begins, creating a huge crystallization pressure. With high water absorption and low porosity, cracks form in the material under this pressure. With a high porosity of the stone, the crystallization pressure is distributed evenly, and new cracks do not form (a vivid example is limestone). Acid resistance is the property of rocks and materials to react with various acids, destroying or transforming rocks. Marble reacts to acids, including food (citric, acetic). Marble, travertine, limestone and dolomite are destroyed by the action of hydrochloric acid. True, it does not occur in nature in a free form, but in cities where chlorides are used to fight snow, this risk factor increases significantly.
All this means that in the exterior decoration of buildings it is better to use rocks that do not collapse under the influence of adverse factors and retain their appearance for a long time, granite and limestone. Limestone is good for basement structures. It is not for nothing that in all large cities located in river valleys and having a long history (London, Paris, Cologne, Moscow), all the plinths of buildings are made of limestone. In Moscow, by the way, the basement of the walls and towers of the Moscow Kremlin is made of limestone. Granite can also be used for the base, but in this case, the movement of salts will go along the masonry joints.

Classification of rocks according to the degree of abrasion

The intensity of the human flow

Textured stone surface treatment

To give the stone additional aesthetics, it is subjected to various textured treatments, which can reveal and emphasize the decorative properties of the stone or, conversely, obscure them. In the process of such processing, the front part of the stone slab is processed with various tools, creating a decorative relief.
Texture "Rock". The rough relief of the stone is obtained by chipping off large pieces from the workpiece. It turns out a natural chipping of a stone with differences in the heights of the relief up to 5 - 15 cm. This texture is performed both mechanically and manually.
Dot texture. Smooth surface with dotted potholes.
Sawn texture. Achieved by processing the stone with diamond circular saws. The result is a rough surface with longitudinal ditches and height differences of up to 5 mm.
Heat treatment. Under the influence of a high-temperature gas jet, the surface of the stone becomes rough, with traces of peeling and a well-defined structure. Height difference - up to 5 mm.
Polished texture. Smooth, slightly rough stone surface with traces of processing with an abrasive tool. Height difference - 2 mm. The pattern, color and structure of the stone are weak in this case, but the general background becomes lighter.
Rough texture. Smooth matt surface without visible traces of abrasive tooling, with a pronounced stone pattern.
Polished texture. Sometimes the polishing process is also called gloss rolling, since this texture is characterized by a mirror-like surface gloss. The smooth surface of the stone clearly reflects the details of objects. Polishing fully brings out and emphasizes the natural color and pattern of the stone.
human flow

ROCK APPLICATION

Granites
Granite (from the Latin "granum" - grain) is the most common rock. It has a pronounced granular-crystalline structure and consists mainly of feldspars, quartz, mica and other minerals. According to the size of the grains, granites are divided into fine-grained, medium-grained, coarse-grained. The color "palette" of granite is extremely rich. Most often there is gray granite of different shades - from light to dark. There is also pink, orange, red, bluish-gray and sometimes bluish-green granite. Exceptionally rare are granites with blue quartz. The following varieties of granite are considered the most valuable in decorative terms: fine-grained light gray with a blue tint, rich dark red and greenish blue. Granite is well polished, retaining a mirror-like sheen of the surface for a long time, it is easy to cut, which allows you to create various textures. To create decorative effects, some varieties of granite are subjected to heat treatment. Light gray granites then acquire a delicate sugar-white hue.
Due to its high mechanical properties and operational properties, granite is widely used in the construction of basement structures, in the cladding of embankments, building facades, as well as floors in places with a large human flow. Fine-grained granite is used in sculpture (because its structure allows impact processing), and coarse-grained granite is used for the construction of monumental structures. Very often, syenites are classified as granites, which differ from granites in less pronounced granularity and the absence of quartz (due to this, they are easier to process). Syenites are darker than granites: they usually have gray, dark gray, gray-blue, dark pink colors. They are used in construction in the same way as granites.

Gabbro
Gabbro is a deep granular-crystalline rock. It has the same structure as granite: fine, medium and coarse grained. Differs in the increased viscosity and resistance to weathering. There is no quartz in gabbro, so the stone is easy to machine, polishes very well and retains its surface shine for a long time. Gabbro is represented by color shades from dark gray-green to black. Due to some transparency of plagioclase, the polished surface of the stone acquires a well-defined depth, which distinguishes gabbro from other black rocks. For example, from basalt. The combination of black polished and light gray chipped looks quite impressive.
gabbro, which is used in the preparation of drawings and ornaments. As a facing material, fine-grained greenish-black and black gabbro are usually used. Gabbro tolerates frost very well. Therefore, it is widely used for cladding facades, finishing public buildings, creating monumental structures, less often in private interiors. Gabbro floors in high traffic areas quickly lose their polish.

labradorites
The name of this stone was given by the Labrador Peninsula, where it was first discovered. Labradorite is a deep granular-crystalline rock, the main component of which is plagioclase labradorite. There are two types of labradorites: black and gray. Black labradorites are more common.
A special decorative effect is given to this stone by shimmering iridescent spots on the surface: blue-green, cornflower blue, golden yellow, red shades. Stones in blue, blue and greenish tones increase the decorative value of the breed. Labradorite is most often used in a polished form. The stone has high strength and frost resistance, which allows it to be successfully used in the exterior decoration of buildings. But it is also used indoors - for facing floors, wall plinths, columns. By the way, black labradorite was used in the construction of the Cathedral of Christ the Savior in Moscow in 1851.

Sandstones
Sandstone is a sedimentary rock composed of cemented sand. The most durable are siliceous sandstones. Sandstones are gray, green, red, yellow, brown and brown. Fine-grained red, chocolate brown and green varieties of sandstone are considered decorative, which are successfully used for exterior cladding. In Moscow and St. Petersburg buildings built in the 19th - early 20th centuries, the cladding of Polish sandstone in gray-green, yellow and pink shades has been well preserved. And the Cathedral Square of the Moscow Kremlin is lined with Lyubertsy sandstone.
However, sandstone is a rather porous material, so it is undesirable to use it for finishing elements in contact with water (first of all, we are talking about basement structures). Sandstones cannot be polished, so the most popular sandstone textures are chipped, sawn, and sometimes polished textures.

Limestones
This is a rock of organic and organo-chemical origin, consisting mainly of calcite, often with an admixture of quartz, clay and sand particles. Often contains the remains of calcareous skeletons of fossil organisms. Limestones are white, light gray, yellowish, less often pinkish. The most valuable in the decorative sense are white limestones with yellow and pink hues. Depending on the structure, limestone is divided into dense, porous and marble-like. Dense limestones are used in the manufacture of slabs for exterior and interior cladding. These include, in particular, the famous Myachkovo, Korbcheev and Kovrov limestones, from which Russian architects built miracles of white stone architecture. Frost-resistant varieties are also found in the limestone group. To be convinced of this, it is enough to look at the perfectly preserved buildings of the 13th-14th centuries. Among the porous limestones, several varieties are also distinguished. For example, oolitic limestones have a coarse-grained texture with rounded calcite formations. Usually they are used as a building material for walls, less often for facade cladding. Shell limestones (shell rocks) are rather porous rocks, consisting of shells of mollusks and their fragments, fastened with lime cement. Some types of shells are considered decorative: for example, pure white, pink, golden yellow with a high content of shells. Shell rocks can be easily processed with a cutting tool, and some types can even be polished (though without obtaining a decorative sheen). Shell rocks are widely used as a building material for walls, as well as for exterior and interior cladding of buildings.

Marble
The name "marble" comes from the Greek "marmaros", which means - brilliant. This granular-crystalline rock appeared as a result of recrystallization of limestone and dolomite under the influence of high temperature and pressure. But in construction, the word "marble" refers not only to this stone, but also to other rocks similar to it. For example, marble-like limestones and dolomites. In the vast majority, marble lends itself well to processing with any tools, which allows you to expand the already rich range of its colors. For example, polishing enhances the pattern and color of marble, grinding reduces its brightness and clarity, and the chipping texture completely hides the pattern, but significantly brightens the overall background. Although this can be attributed to any stone. According to decorative properties, processing possibilities and breadth of application, marble is divided into white, gray and colored.
White marble contains practically no impurities, so it is often homogeneous, has a fine and medium-grained structure. This marble is easy to process. Fine-grained white marble is considered the most valuable, which is famous for its warm tone and the fact that it is translucent. This stone is also called statuary, as it is widely used in sculpture. White marble is considered a very capricious, domestic stone, which is associated with its special structure: it is poorly protected from staining and yellowing. This applies primarily to inexpensive varieties. Such marble should be used with caution when facing facades. Of course, its technical characteristics make it possible to survive both severe frosts and mechanical damage, but after a while it may lose its beauty and brilliance, fade and become covered with yellow spots. Gray marble is most often heterogeneous and has a layered color. The characteristic pattern of gray marble is “cloudy” and “snow-landscape”. This type of marble is easy to process and polish. It, like white marble, is used for exterior and interior cladding. Among colored marble, blue-blue varieties are considered rare. All of them lend themselves well to polishing. The heat-resistant qualities of marble make it possible to use this stone for outdoor cladding of fireplaces or rooms associated with high temperatures. The water absorption coefficient of marble, like that of granite, is quite low, so it can be used in the construction of pools, bathtubs and fountains. But it is best to finish the interiors with marble.

Quartzite
Fine-grained rocks that were formed during the recrystallization of siliceous sandstones and consist mainly of quartz. They come in gray, pink, yellow, raspberry red, dark cherry and sometimes white. Quartzite is considered a very beautiful stone, especially its crimson red and dark cherry varieties. The chipping texture significantly brightens the general background of the stone, which is often used by combining it with the contrasting color of the polished texture. Quartzite is very hard and difficult to machine, but can be polished to a very high standard.
This stone is used in monumental art and in the construction of unique architectural structures (for example, in the construction of the Church of the Savior on Spilled Blood). In addition, for many centuries, quartzite was also used as a ritual stone: the sarcophagus of Napoleon, Alexander II, the upper part of the Lenin Mausoleum, was made from it.

Slate
This dense and hard rock was formed mainly from highly compacted clay, which partially recrystallized under high unilateral pressure. A characteristic feature of shale is the ability to split into thin plates. Colors - dark gray, black, gray-brown, red-brown. Slate is a fairly durable material, amenable to processing (stratified into thin plates), some types can be polished. However, slates are often used without any processing at all, because their surface at the split site is quite decorative in itself. Slate is used in exterior and interior wall and floor cladding. For example, the floors of St. Isaac's Cathedral in St. Petersburg are partly made of slate. In Europe, they often cover the roofs of houses.

Semiprecious stones
These include mainly rocks, which are also called decorative and ornamental stones: jasper, onyx, opal, malachite, lapis lazuli. These stones are much rarer and valued much more than others. It is quite expensive to veneer large areas of the surface with them, therefore, most often small interior elements are trimmed with semi-precious stones: details of columns, window sills, bathrooms, as well as mosaic fragments. One of the most common decorative and ornamental stones is considered to be onyx (translated from Greek as “nail”). Onyxes have a layered or radical-radiant structure. There are white, light yellow, yellow, brown, dark brown, pale green colors. The pattern alternates stripes of different shades. Most marble onyxes are translucent, sometimes to a depth of 30 - 40 mm. Onyx is well processed by cutting and grinding tools and lends itself to high quality polishing. A vivid example of the use of onyx in interior decoration is stained-glass windows at the Dynamo metro station in Moscow.

WHAT PROBLEMS COULD HAVE WITH STONE FACING

Yellowing is a problem in the first place for all light-colored marbles. Some types of marble, such as "Koelga", may turn yellow on their own, especially if the external environment contributes to this (frost, temperature changes). Marble, unlike granite, is considered a very capricious, domestic stone, so it should be used with caution when facing facades. The appearance of a yellow spot may have another, “mechanical” reason. For example, if during laying some metal object (for example, a nail) accidentally fell into a concrete screed. Under the influence of water and air, it can begin to rust. This process will immediately affect the marble slab - after all, stains show through well on marble. Unfortunately, this section of the marble slab cannot be cleaned. To prevent the marble from turning yellow, it must be laid on white adhesives. In the kitchen, marble cladding should be used with care, especially if you are making a countertop out of marble. If, nevertheless, you cannot do without a marble countertop, it must be protected with hydrophobic chemical compounds. Tarnishing threatens mainly polished marbles laid on the floor. Over time, the brilliant polish of marble wears off, giving way to a dull roughness. Marble is more susceptible to abrasion than, for example, granite. Therefore, polished marble is not recommended to be laid in places of heavy traffic: in the hallway, hall, etc. To prevent the marble from tarnishing, a polished stone with wax can be used from the very beginning. Here the situation is the same as with the wooden floor. If you cover it with varnish, then it will be erased over time, and to restore the appearance, you will need to remove the old varnish and apply a new one. If the tree is covered with wax, then in the future, after applying special means, it easily restores its luster. It's the same with marble. A tarnished polished marble floor needs to be refinished, while waxed marble needs to be re-coated with a special compound. The gloss is deeper and matte, not as mirror-like as when polished. In addition, polished marble absorbs water, while waxing creates a hydrophobic protection.
Strong slip is a property of polished granite laid outdoors (on the porch, on the stairs) or on the floor. The slip coefficient of granite with this type of processing is very high.
If we add to this weather conditions such as rain or snow, then walking on a polished surface becomes traumatic. Therefore, outdoors it is not recommended to use polished granite without anti-slip strips applied using corundum or heat treatment.

CARE OF NATURAL STONE

Now there are various chemical agents that allow you to preserve the natural color and luster of natural stone for a longer time. A special putty mass, matched by color, can eliminate the smallest cracks and pores on the surface of the stone, which are formed during its mechanical processing. This will protect the cladding from the ingress of microorganisms. Depending on the area of application of the stone, it is treated with a water- or dirt-repellent composition. In addition, there are tools for the constant care of stone products. For example, mild cleansing shampoos for daily care and for one-time use (for example, to remove stains). Special polishes add shine to polished surfaces, dirt-protective agents reduce the risk of staining stone veneer, various protective substances prevent scratches and other mechanical damage. This, of course, is not all chemical compositions intended for stone care. In fact, there are many more.

Major sedimentary rocks of organic and chemical origin

Classification of sedimentary clastic (terrigenous) rocks

Lecture topic: 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 bowels of the Earth. 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 of the 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. Universe - ϶ᴛᴏ 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. An example of such a system is the Milky Way galaxy, 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.

The structure of the 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 ʼʼyellow dwarfʼʼ, 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. 99.886% of the entire mass of the solar system is concentrated in the Sun. 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 the shape of the Earth, we understand the shape of its solid body, formed by the surface of the continents and the bottom of the seas and oceans. Geodetic measurements have shown that the simplified shape of the Earth approaches 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 geoid, which literally means ʼʼearthlikeʼʼ. The surface of the geoid in the seas and oceans corresponds to the surface of the water, and on the continents - 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, the general features of the structure of the Earth were revealed and it was 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. Οʜᴎ are 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 commonly 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 called the angle of deviation of the magnetic needle of the compass from the geographic meridian. The declination must 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, due to which magnetic anomalies occur on the surface of the Earth. 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 residual 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. Οʜᴎ 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 a shallow depth not exceeding 30 m. At a certain depth from the surface there is a belt of constant temperature, equal to the average annual temperature of the area. In the vicinity of Moscow, at a depth of 20 m from the surface, a constant temperature is observed equal to +4.2 0. 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 10 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 step 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 the residual heat that has been preserved since 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%). At the same time, 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. The air masses of the atmosphere 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 basic 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 are 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. For this reason, the salt composition of ocean waters differs sharply from the composition of river waters. In ocean waters, chlorides (88.7%) - NaCl, MgCl 2 and sulfates (10.8%) prevail, 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 depths 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. The study of the deep structure of the Earth is one of the main tasks of modern geology. Only the uppermost (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 ʼʼ seismaʼʼ - 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. Today, the available data confirm the spherically - symmetrical structure of the Earth's interior. Back in 1897 ᴦ. Professor of the University of Göttingen E. Wiechert expressed the idea of the shell structure of the Earth, which consists of an iron core, a stone mantle and the earth's crust. In 1910 ᴦ. Yugoslav geophysicist A. Mohorovichic, studying the features of the propagation of seismic waves during an earthquake in the area of the city of Zagreb, established at a depth of 50 km the interface between the crust and the mantle. Subsequently, this surface was identified at various depths, but they were always clearly traced. She was given the name ʼʼsurface of Mohorovichićʼʼ, 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 1936ᴦ. 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 higher and lower 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, therefore 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 alloy of iron and nickel.

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 ᴦ. 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 ᴦ.), Eight elements (in weight%) are most common in the composition of the earth's crust, making up over 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 basic types: continental, oceanic and intermediate. Continental consists of a sedimentary layer 20-25 km thick, granite (granite-metamorphic) up to 30 km thick and basalt 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 consist 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

Control 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. Rock - ϶ᴛᴏ natural, most often, solid body, consisting of one (limestone, anhydrite) or several minerals (polymictic sandstone, granite). In other words, this 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 ϶ᴛᴏ 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 into them or removal 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 deposition of these mineral substances mainly in the aquatic, 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 pathway 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 compose 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, in order for a rock to contain oil, gas and water, it must be qualitatively different from rocks that do not contain fluids, ᴛ.ᴇ. it must have pores, cracks or cavities, must be porous. Today, most of all industrial accumulations of oil and gas contain sedimentary detrital (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 function as insulators for oil and gas saturated bodies. Tables 1 and 2 show lithofacies of rocks containing oil and gas and serving as seals.

Table 1

Breed group	Debris dimensions, mm	Loose rocks	cemented rocks
Rounded Debris	Unrounded wreckage	Rounded debris	Unrounded wreckage

Coarse clastic (psephites)	Large > 200	boulders	lumps	boulder conglomerates	blocky breccias
Medium 200-10	pebble (pebble)	rubble	pebble conglomerate	breccia
Small 10-2	Gravel is oil and gas saturated	gruss can be oil and gas saturated	gravelstones are oil and gas saturated (gravel conglomerates)
Sandy (psammites)	2-1	Coarse-grained sands are very often oil and gas saturated	Coarse-grained sandstones are very often oil and gas saturated
1-0,5	Coarse-grained sands are very often oil and gas saturated	Coarse-grained sandstones are very often oil and gas saturated
0,5-0,25	Medium-grained sands are very often oil and gas saturated	Medium-grained sandstones are very often oil and gas saturated
0,25-0,1	Fine-grained sands are very often oil and gas saturated	Fine-grained sandstones are very often oil and gas saturated
Silty rocks (aleurites)	0,1-0,01	silt (loess, sandy loam, loam) is often oil and gas saturated	siltstone is often oil and gas saturated
Clay rocks (Pelites)	< 0,01	clay (physical) is never oil and gas saturated (fluid seal)	argillite is not oil and gas saturated (fluid seal)

Table 2.

Breed group	Organogenic rocks	Chemogenic rocks

Carbonate	coral limestone - (СaCO 3) (very often oil and gas saturated) shell limestone - (СaCO 3) (very often oil and gas saturated) detritus limestone - (СaCO 3) (very often oil and gas saturated) Chalk (as a rule, it does not happen very often oil and gas saturated) Marl ( rarely fractured oil and gas saturated)	limestone dense limestone oolitic (very often oil and gas saturated) calcareous tuff sinter limestone dolomite - (СaMgCO 3) 2 (very often oil and gas saturated) marl siderite (rarely fractured is oil and gas saturated)
Siliceous	diatomite flask	siliceous tuff flint
Ferrous	-	limonite
Halogen	-	rock salt (highest quality sealant)
sulfate	-	Gypsum CaSO 4 *H 2 O, anhydrite CaSO 4 (usually seals)
Aluminum	-	Bauxite
Phosphate	-	Phosphorite

Analysis of tables 1 and 2 shows that most terrigenous rocks in nature are oil and gas saturated. Therefore, it is no coincidence that for the first time oil and gas were discovered in these rocks and for a long historical period they were extracted from these rocks. And only in the last decades of the twentieth century in many regions were discovered huge reserves of oil and gas in carbonate strata. This is, first of all, in coral, detritus and oolitic limestones and dolomites. So, the following lithofacies of clastic sedimentary rocks are very often oil-and-gas-bearing rocks: sands and sandstones, siltstones and silts, gravelstones and gravels. From the group of carbonate rocks, the following lithofacies serve as oil and gas bearing rocks: coral limestone, shell limestone, detritus and oolitic limestones and dolomites.

The following lithofacies of sedimentary rocks do not contain oil and gas, but perform the function of insulators: rock salt - the highest quality fluid seal, clay, mudstone (non-fractured), marl (not fractured), gypsum and anhydrite are dense, limestone is dense pelitomorphic, chalk and other strong and not fractured rocks. Individual porous sedimentary rocks can only contain industrial hydrocarbon accumulations when they are interbedded with insulating rocks that do not contain oil and gas.

Main literature: 4, 5

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 shale began to form 130-140 million years ago in the Lower Volga age of the Jurassic period. 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, and others. 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 animal 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 the calcareous remains of microscopic marine organisms such as foraminifera or the calcareous remains of numerous species of 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 of 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 high-molecular aromatic compounds with a high concentration of carbon and a lower concentration of 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 the 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 rocks, the form of the constituent parts, which is determined by the nature of the organisms, is of great importance. 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 is distinguished by the fact that shell fragments are mostly 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 in the 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 is Novodmitrievskoye (Seversky district): 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 the 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 roasting for lime, to obtain wall blocks and for the preparation of fodder flour 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

The Krasnodar Territory 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. In recent 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 the Sochi National Park (Fig. 4), which is part of 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). 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 process oil in large quantities 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 to treat wastewater from metals and organic substances, although its low cost and high degree of purification can make it the most demanded 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 the production of 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.

Chemical sedimentary rocks are formed by precipitation from aqueous solutions of chemical precipitation. These rocks include: various limestones, calcareous tuff, dolomite, anhydrite, gypsum, rock salt, etc. A common feature is their solubility in water and fracturing.

Organogenic sedimentary rocks formed as a result of the accumulation and transformation of the remains of the animal world and plants, are characterized by significant porosity, dissolve in water. Organogenic rocks include: shell limestone, diatomite, etc.

The vast majority of the breeds of these two groups are of mixed (biochemical) origin.

Groups of chemical and organogenic rocks are usually divided into subgroups according to composition:

carbonate,

siliceous,

glandular,

halogen,

sulfate,

phosphate and etc.

Combustible rocks stand out, or caustobioliths.

Carbonate rocks

Limestone - a rock composed of the mineral calcite. It is determined by a vigorous reaction with HCl. Color white, yellowish, gray, black. Limestones are of organogenic and chemical origin.

Organogenic limestones consist of the remains of organisms, which are rarely preserved completely, more often they are crushed and also changed by subsequent processes. If the limestone consists of whole shells, it is called shell limestone, and if it is made of broken shells, it is called detritus limestone.

A variety of organogenic limestone is chalk, consisting mainly of the smallest shells of foraminifers, powdery calcite and shells of the simplest microscopic algae. chalk- white earthy rock, widely used as a raw material for Portland cement, whitewashing material and writing chalk.

Limestones of chemical origin occur in the form of dense fine-grained masses:

oolitic limestones- accumulations of small balls of a shellish or radial-radiant structure, connected by lime cement;

calcareous tuff(travertine) - a highly porous rock that forms in places where groundwater rich in dissolved lime bicarbonate comes out to the earth's surface, from which an excess of dissolved calcium carbonate quickly falls out when carbon dioxide volatilizes or when the water cools;

Sinter formations of calcite- stalactites, stalagmites (Fig. 9).

Limestones are used as a building material, fertilizer, in the cement industry, in metallurgy (as a flux).

Dolomite CaMg(CO 3) 2 – consists of a mineral of the same name. Outwardly similar to limestone, differs from it in the reaction with hydrochloric acid (reacts in powder), yellowish-white, sometimes brownish color, greater hardness (3.4–4). Dolomites are formed in marine basins mainly as secondary products due to limestones: magnesium dissolved in water interacts and combines with limestone calcite. This process, called dolomitization, leads to the complete destruction of organic residues. Thin layering is not typical for dolomites; they often form powerful rocky cliffs. Dolomites are used as a flux, refractory and fertilizer.

Marl - calcareous-argillaceous rock, consisting of calcite and clay particles (30–50%). Its color is pale-yellow, brownish-yellow, white, gray. Outwardly, marl is little different from limestone; it is recognized by the nature of the reaction with hydrochloric acid, from a drop of which a dirty-damp or whitened spot remains on the surface of the marl, due to the concentration of clay particles at the reaction site. Marl is formed in the seas and lakes (Fig. 10).

kpeominous rocks

They can be both chemical (siliceous tuff) and organogenic origin (flint, diatomite, flask).

Siliceous tuff (geyserite) consists of a porous (rarely dense) mass of opal. The color of the breed is light, sometimes variegated. Tuff is formed when hot springs come to the surface, in the water of which silica is dissolved.

Flint- a fine-grained spotted or banded aggregate of chalcedony, a cryptocrystalline variety of quartz. It is formed from the decayed skeletal remains of siliceous organisms, that is, from silica gel, which, gradually losing water and compacting, turns into opal and then into chalcedony. Often contains inclusions of organic residues. The color is predominantly gray to black or brown, occurs as nodules (nodules) in Cretaceous limestones, never forming coherent layers. In the Stone Age, due to its high hardness (equal to 7), flint served as an important material for the manufacture of weapons and tools. It is currently used as a grinding and polishing material.

diatomaceous earth - porous, light, white, light yellow loose or cemented rock, easily pounded into a fine powder, greedily absorbs water. It consists of the smallest opal shells of diatoms, skeletons of radiolarians and sponge needles, grains of quartz, glauconite, and clay minerals are found. It is used as a filter material and to obtain liquid glass. Diatomite is formed from diatomaceous silt located at the bottom of lakes and seas.

Flask – siliceous, porous rock of white, gray, black color, often with conchoidal fracture. The hardest varieties of it, when struck, break with a characteristic ringing sound. It consists of opal grains and an insignificant admixture of remains of siliceous skeletons of organisms cemented with siliceous matter.

ferruginous rocks

Among the rocks of this subgroup, siderite (FeCO 3 - iron spar) and limonite are the most common.

Limonite- a mechanical mixture of iron hydroxide with sandy or clay material. In appearance, these are most often legume (oolitic) or sinter masses. The color is yellow, brown, accumulates in swamps and lakes, therefore it is often called swamp or lake ore.

halide rocks

From halide rocks most common rock salt, mineral halite(NaCl), in nature it is usually colored gray, reddish-yellowish or reddish. Rock salt usually occurs in layers, has a coarse grained structure and glistens in the sun. A third of all salt produced is used as food for people and animals, the rest is used in industry for technical purposes. In the deposit, layers of rock salt often alternate with layers sylvina(KCl).

Sulfuric rocks

The most widespread gypsum and anhydrite. They are formed as a result of precipitation from aqueous solutions in shallow lakes, lagoons of arid zones, where, due to intense evaporation, supersaturated solutions arise.

Halide and sulfate salts usually occur in the form of layers among clayey rocks; the latter protect them from dissolution by groundwater.

Gypsum(CaSO 4 ∙ 2H 2 O) – white or lightly tinted; coarse-grained or fibrous, with a silky sheen. It differs from a similar anhydrite having a hardness of 3–4 by a lower hardness of 1.5–2. Widely used in construction. By firing gypsum, 75% of crystallization water is removed from it, but if water is added to the fired building gypsum, it quickly absorbs it again, restoring its original water content, which is accompanied by an increase in volume. This is the basis for the technical use of gypsum as a cement and binder.

Anhydrite(CaSO 4) - this is the name of both the salt rock itself and the mineral that composes it, it looks like rock salt, whitish-gray, yellowish, bluish in color, but has a fine-grained structure and does not have a salty taste. It is used in the production of mineral fertilizers and in construction. Anhydrite layers are dangerous in tunnel construction, as they swell extremely strongly when water enters and, as a result, can compress the tunnel walls.

Phosphate rocks

These include many sedimentary rocks enriched in calcium salts of phosphoric acid with a P 2 O 5 content of up to 12–40% or more. calcium phosphates are more common apatite.

As part of phosphorites admixtures of quartz, calcite, glauconite, remains of radiolarians, diatoms and other organic substances are observed. Phosphate rocks occur in the form of nodules and beds. They are formed both chemogenic and biogenic in the seas and on the continents (in lakes, swamps, caves). In the seas, phosphorites appear when chemical precipitation occurs at depths of 50 to 150 m. . The color of phosphorites is gray, dark gray, black. They are used as raw materials for fertilizer (superphosphate) and phosphorus production.

Caustobioliths

This is a large group of combustible carbonaceous rocks of organic composition and organogenic origin, and therefore, according to a strict definition, are not real rocks. But, on the other hand, they are an integral part of the solid earth's crust and are partially changed to such an extent that their organic nature can no longer be established, and therefore they are classified as sedimentary rocks.

Caustobioliths are formed by coalification of accumulations of plant material. The carbonification process consists in a gradual increase in the relative content of carbon in organic matter due to its depletion in oxygen (and to a lesser extent in hydrogen). Increased pressures and temperatures associated with mountain-forming and volcanic processes cause diagenetic and metamorphic transformations of coals.

Caustobiolites are solid (peat, brown coal, coal, anthracite, graphite, oil shale, asphalt, ozocerite), liquid (oil) and gaseous (combustible gases). The properties of solid caustobiolites are given in Table. eight.

Table 8

Properties of solid caustobiolites

Caustobioliths			Density, g / cm 3	Calorific value ability
		(no shine)		1500-2000 cal (6280–8374 J)
Brown coal	brownish black			2000–7000 cal (8374–29 308 J)
Coal				7000-8500 cal (29308–35588 J)
Anthracite		metalloid		8500-9000 cal (35588–37681 J)
		Metal

Peat consists of semi-decomposed marsh and woody plant remains containing carbon (35–59%), hydrogen (6%), oxygen (33%), nitrogen (2.3%) in its composition. Peat is a loose, brownish-brown or black rock. Depending on what plant residues peat consists of, there are sphagnum, sedge and reed peat. Raw peat contains up to 85–90% water; when dried to an air-dry state, it still contains up to 25% water. Peat is used for the preparation of fertilizers and technical wax.

Brown coal contains 67–78% carbon, 5% hydrogen and 17–26% oxygen. This is a dense dark brown or black mass with an earthy fracture, a matte sheen, a dark brown streak. Hardness 1–1.5; density 1.2 g/cm 3 . Brown coals contain impurities of clay minerals, which cause their high ash content.

Coal contains up to 82–85% carbon. The breed is black, dense, matte luster, black streak. Hardness from 0.5 to 2.5; density 1.1–1.8 g / cm 3.

Anthracite contains 92–97% carbon. It is a hard brittle grayish-black rock with a strong semi-metallic luster. The fracture is granular, conchoidal. Hardness 2.0–2.5; anthracite density 1.3–1.7 g / cm 3. The line color is light black. Formed at high pressure and temperature (not lower than 300 °C).

Graphite– crystalline carbon; this is a highly metamorphosed coal, but it can also be of inorganic origin.

oil shale - shale, clay or marl rocks, which include organic matter in the form of dispersed sapropel (putrefactive silt). Oil shales are thin-layered, have a dark gray or brown color; they were formed in the process of accumulation of dead microalgae and plankton. They are used as local fuel and for the production of liquid and gaseous volatile substances, from which oil products, gas, sulfur, drying oil, tanning extracts, paints, pesticides for plant protection are obtained.

Oil is a mixture of liquid and gaseous hydrocarbons. The share of other elements (nitrogen, oxygen, sulfur, etc.) accounts for 1–2%. In appearance it is an oily liquid, the color varies from almost white, yellow to dark brown; the density also changes accordingly - from 0.76 to 1.0 g / cm 3. Only asphalt oils have a slightly higher density.

Amber (C 10 H 16 O) - hardened resin of coniferous trees that grew 25-30 million years ago. Amber is amorphous. Its color is white, yellow, brownish. Hardness 2–2.5. Transparent or translucent. The gloss is oily or matte. Density 1.05–1.1 g / cm 3, melts at a temperature of 300 ° C. It burns with a pleasant smell. When rubbed, it is easily electrified. It occurs in the form of blocks among sandy rocks. It is used in the jewelry industry and in certain medical preparations.

The main sedimentary rocks of organic and chemical origin are given in Table. 9.

Table 9

Main rocks of organic and chemical origin

Name subgroups	Organogenic rocks	Chemogenic rocks
Carbonate	coral limestone, shell limestone, detritus limestone, chalk, marl	dense limestone, oolitic limestone, calcareous tuff, sinter limestone, dolomite, siderite, marl
Siliceous	diatomite, flask	tripoli, siliceous tuffs, flint
glandular
Halogen		rock salt
sulfate		gypsum, anhydrite
Aluminum
Phosphate		phosphorites
Caustobioliths	peat, fossil coals, oil shale, oil, asphalt, ozocerite, amber