Anthropologists have been able to extract the DNA of ancient hominins from sediments in caves. Types, genesis and mineralogy of cave deposits Scheme of speleoform formation

Water not only creates caves, but also decorates them. Chemogenic formations that make the caves amazingly beautiful and unique are extremely diverse. They are formed over thousands of years. The main role in their formation is played by infiltration water seeping through the thickness of carbonate rocks and dripping from the ceiling of karst caves. In the past, these forms were called droppers, and they distinguished between “upper drip” and “lower drip”.

For the first time, the origin of sinter formations was explained by the great Russian scientist M.V. Lomonosov: “The upper drip is similar to ice icicles in everything. Hanging on the vaults of a natural adit. Through the icicles, of which sometimes many different lengths and thicknesses have grown together, vertical wells of different widths pass from above, from which mountain water drops, increases their longitude and produces a lower drop, which grows from falling drops from the upper icicles. The color of the capi, and especially the upper one, is for the most part, like the scale, white, grayish; sometimes, like a good yar, green, or completely feathery " .

Sinter formations usually form after the appearance of underground cavities (epigenetic) and very rarely simultaneously with them (syngenetic). The latter are obviously not observed in karst caves.

Chemogenic deposits Caves have long attracted the attention of researchers. Meanwhile, the questions of their classification and typification have been extremely poorly developed until recently. Among the special studies, the work of V.I. Stepanov (1971) stands out, which subdivides the mineral aggregates of caves into three types: stalactite-stalagmite crust (this includes crystallization products from freely flowing solutions, i.e. stalactites, stalagmites, stalagnates, draperies, sagging on the walls and floors of caves), corallites (this type includes mineral aggregates that arose from capillary water films on the surface of underground cavities and sinter forms) and antholiths (this type is represented by parallel-fibrous aggregates of easily soluble minerals twisting and splitting during growth - gypsum, halite and etc.). Although this typification is based on a genetic classification trait, it is theoretically not sufficiently substantiated.

Of greatest interest are the classifications of chemogenic forms proposed by G. A. Maksimovich (1963) and Z. K. Tintilozov (1968). Based on these studies, chemogenic formations can be divided into the following main types: sinter, colomorphic, and crystalline.

sinter formations, which are widespread in caves, are divided into two large groups according to their shape and method of origin: stalactites, formed due to a calcareous substance released from drops hanging on the ceiling, and stalagmites, formed due to a substance released from fallen drops.

Among sinter stalactite formations, gravitational (thin-tube, cone-shaped, lamellar, curtain-shaped, etc.) and anomalous (mainly helictites) are distinguished.

Particularly interesting are thin-tubular stalactites, sometimes forming whole calcite thickets. Their formation is associated with the release of calcium carbonate or halite from infiltration waters. Leaking into the cave and getting into new thermodynamic conditions, the infiltration waters lose part of the carbon dioxide. This leads to the release of colloidal calcium carbonate from a saturated solution, which is deposited along the perimeter of a drop falling from the ceiling in the form of a thin roller (Maksimovich, 1963). Gradually growing, the rollers turn into a cylinder, forming thin-tubular, often transparent stalactites. The inner diameter of tubular stalactites is 3-4 mm, the wall thickness usually does not exceed 1-2 mm. In some cases, they reach 2-3 and even 4.5 m in length.

Cone-shaped stalactites are the most common among stalactites (Fig. 3). Their growth is determined by water flowing down a thin cavity located inside the stalactite, as well as by the influx of calcite material along the surface of the incrustation. Quite often, the internal cavity is located eccentrically (Fig. 4). From the opening of these tubes every 2-3 minutes. dripping clear water. The sizes of cone-shaped stalactites, located mainly along cracks and indicating them well, are determined by the conditions of calcium carbonate supply and the size of the underground cavity. Usually stalactites do not exceed 0.1-0.5 m in length and 0.05 m in diameter. Sometimes they can reach 2-3, even 10 m in length (Anakopia cave) and 0.5 m in diameter.

Of interest are spherical (onion-shaped) stalactites formed as a result of blockage of the tube opening. Aberration thickenings and patterned outgrowths appear on the surface of the stalactite. Spherical stalactites are often hollow due to the secondary dissolution of calcium by water entering the cave.

In some caves, where there is a significant movement of air, there are curved stalactites - anemoliths, the axis of which is deviated from the vertical. The formation of anemoliths is determined by the evaporation of hanging water droplets on the leeward side of the stalactite, which causes it to bend in the direction of the air flow. The bending angle of individual stalactites can reach 45°. If the direction of air movement periodically changes, then zigzag anemoliths are formed. Curtains and draperies hanging from the ceiling of caves have a similar origin with stalactites. They are associated with infiltration water seeping along a long fissure. Some curtains, composed of pure crystalline calcite, are completely transparent. In their lower parts, stalactites with thin tubes are often located, at the ends of which water droplets hang. Calcite deposits can look like petrified waterfalls. One of these waterfalls is noted in the grotto of Tbilisi Anakopia cave. It is about 20 meters high and 15 meters wide.

Helictites are complexly built eccentric stalactites that are part of a subgroup of anomalous stalactite formations. They are found in various parts of karst caves (on the ceiling, walls, curtains, stalactites) and have the most diverse, often fantastic shape: in the form of a curved needle, a complex spiral, a twisted ellipse, a circle, a triangle, etc. Acicular helictites reach 30 mm in length and 2-3 mm in diameter. They are a single crystal, which, as a result of uneven growth, changes its orientation in space. There are also polycrystals that have grown into one another. In the section of acicular helictites, growing mainly on the walls and ceiling of caves, the central cavity is not traced. They are colorless or transparent, their end is pointed. Spiral helictites develop mainly on stalactites, especially thin tubular ones. They are made up of many crystals. Inside these helictites, a thin capillary is found, through which the solution reaches the outer edge of the aggregate. Water droplets formed at the ends of helictites, unlike tubular and conical stalactites, do not come off for a long time (many hours). This determines the extremely slow growth of helictites. Most of them belong to the type of complex formations that have a bizarrely intricate shape.

The most complex mechanism of the formation of helictites is currently not well understood. Many researchers (N. I. Krieger, B. Zhese, G. Trimmel) associate the formation of helictites with blockage of the growth channel of thin-tubular and other stalactites. Water entering the stalactite penetrates into the cracks between the crystals and comes to the surface. This is how the growth of helictites begins, due to the predominance of capillary forces and crystallization forces over gravity. Capillarity is, apparently, the main factor in the formation of complex and helical helictites, the direction of growth of which initially largely depends on the direction of intercrystalline cracks.

F. Chera and L. Mucha (1961) by experimental physicochemical studies proved the possibility of precipitation of calcite from the air of caves, which causes the formation of helictites. Air with a relative humidity of 90-95%, supersaturated with tiny droplets of water with calcium bicarbonate, turns out to be an aerosol. Droplets of water that fall on ledges of walls and calcite formations quickly evaporate, and calcium carbonate precipitates. The highest growth rate of a calcite crystal goes along the main axis, causing the formation of needle-shaped helictites. Therefore, under conditions where the dispersion medium is a substance in a gaseous state, helictites can grow due to the diffusion of a dissolved substance from the surrounding aerosol. The helictites created in this way ("aerosol effect") are called "cave hoarfrost".

Along with the clogging of the feeding channel of individual thin-tubular stalactites and the “aerosol effect”, the formation of helictites, according to some researchers, is also influenced by the hydrostatic pressure of karst waters (L. Yakuch), air circulation features (A. Vihman) and microorganisms. These provisions, however, are not sufficiently substantiated and, as studies of recent years have shown, are largely debatable. Thus, the morphological and crystallographic features of eccentric sinter forms can be explained either by capillarity or by the influence of aerosol, as well as by a combination of these two factors.

Of greatest interest are questions about the structure of stalactites, the features of their formation and growth rate. A. N. Churakov (1911), N. M. Sherstyukov (4940), G. A. Maksimovich (1963), and Z. K. Tintilozov (1968) dealt with these questions.

Stalactites consist mainly of calcite, which accounts for 92-100%. Calcite crystals have tabular, prismatic and other shapes. In the longitudinal and transverse sections of the stalactite, spindle-shaped calcite grains up to 3-4 mm long can be traced under the microscope. They are located perpendicular to the growth zones of the stalactite. The gaps between spindle-shaped grains are filled with fine-grained (up to 0.03 mm in diameter) calcite. At high magnification, individual grains of fine-grained calcite show a fine-grained granular structure (Fig. 5). Sometimes they contain a significant amount of amorphous and clayey-calcareous material. The contamination of the stalactite with clayey pelitic material, which can be traced in the form of thin parallel layers, determines its banded structure. Banding goes across the strike of crystals. It is associated with a change in the content of impurities in the incoming solution during the growth of the stalactite.

The growth rate of stalactites is determined by the rate of influx (frequency of dripping) and the degree of saturation of the solution, the nature of evaporation, and especially the partial pressure of carbon dioxide. The frequency of droplets falling from stalactites varies from a few seconds to many hours. Sometimes the fall of drops hanging at the ends of the stalactite is not observed at all. In this case, apparently, the water is removed only by evaporation, which causes the extremely slow growth of stalactites. Special studies conducted by Hungarian speleologists have shown that the water hardness of drops hanging from a stalactite is greater than that of falling ones, by 0.036-0.108 mEq. Consequently, the growth of a stalactite is accompanied by a decrease in the calcium content in the water and the release of carbon dioxide. These studies also established a significant change in the hardness of stalactite waters during the year (up to 3.6 mEq), with the lowest hardness observed in winter, when the carbon dioxide content in the water decreases due to the weakening of the vital activity of microorganisms. Naturally, this affects the growth rate and shape of stalactites in different seasons of the year.

Of particular interest are direct observations (still few) of the growth rate of stalactites. Thanks to them, it was possible to establish that the intensity of growth of calcite stalactites in various underground cavities and in various natural conditions, according to G. A. Maksimovich (1965), varies from 0.03 to 35 mm per year. Halitic stalactites grow especially fast. Under conditions of inflow of highly mineralized sodium chloride waters, the growth rate of stalactites at the Shorsuysky mine (Central Asia, Alai Range), according to the studies of N.P. Yushkin (1972), varies from 0.001 to 0.4 mm per day: reaching in some cases 3 .66 mm per day, or 1.336 m per year.

Stalagmites constitute the second large group of sinter formations. They form on the floor of karst caves and usually grow towards stalactites. Drops falling from the ceiling hollow out a small (up to 0.15 m) conical pit in the deposits of the floor of the caves. This hole is gradually filled with calcite, which forms a kind of root, and the upward growth of the stalagmite begins.

Stalagmites are usually small. Only in some cases they reach a height of 6-8 m with a diameter of the lower part of 1-2 m. In the areas where they connect with stalactites, calcite columns, or stalagnates, of the most diverse form appear. Patterned or twisted columns are especially beautiful.

Stalagmites have many names depending on their shape. There are conical, pagoda-shaped, palm, stalagmites-sticks, corallites (tree-shaped stalagmites that look like coral bushes), etc. The shape of stalagmites is determined by the conditions of their formation and, above all, by the degree of watering of the cave.

Very original are the stalagmites, which look like stone lilies in the grotto of Iberia Anakopia cave. Their height reaches 0.3 m. The upper edges of such stalagmites are open, which is associated with the spraying of water drops falling from a great height and the accumulation of calcium carbonate along the walls of the formed pit. Interesting stalagmites with rims, reminiscent of candlesticks (grotto of Tbilisi Anakopia cave). Rims are formed around periodically flooded stalagmites (Tintiloz, 1968).

There are eccentric stalagmites. Their curvature is often caused by the slow movement of the scree on which they form. The base of the stalagmite in this case gradually moves down, and drops falling on the same place bend the stalagmite towards the top of the scree. Such stalagmites are observed, for example, in the Anakopia cave.

Stalagmites are characterized by a layered structure (Fig. 6). In the transverse section, concentric white and dark layers alternate, the thickness of which varies from 0.02 to 0.07 mm. The thickness of the layer around the circumference is not the same, since the water falling on the stalagmite spreads unevenly over its surface.

Research by F. Vitasek (1951) showed that the growing stalagmite layers are a semi-annual product, with white layers corresponding to the winter period, and dark layers to the summer period, since warm summer waters are characterized by an increased content of metal hydroxides and organic compounds compared to winter period waters. White layers are characterized by a crystalline structure and a perpendicular arrangement of calcite grains to the surface of the layers. The dark layers are amorphous, their crystallization is prevented by the presence of colloidal iron oxide hydrate.

With a strong increase in the dark layers, an alternation of many white and dark very thin layers was revealed, which indicates a multiple change in the conditions of seepage of infiltration water during the year.

A strict alternation in cross section of white and dark layers is used to determine the absolute age of stalagmites, as well as the underground cavities in which they form. The calculations give interesting results. Thus, the age of a stalagmite from the Kizelovskaya cave (Middle Urals), reaching 68 cm in diameter, was determined at 2500 years (Maksimovich, 1963). The age of stalagmites of some foreign caves, determined by semi-annual rings, was 600 thousand years. (According to the research of F. Vitasek, in the Demänovskie caves in Czechoslovakia, a 1 mm stalagmite is formed in 10 years, and 10 mm in 500 years.) This interesting method, which is becoming more and more widespread, is still far from perfect and needs to be clarified .

In a longitudinal section, a stalagmite consists, as it were, of many thin caps put on each other. In the central part of the stalagmite, the horizontal calcite layers fall sharply down towards its edges (see Fig. 6).

The growth rate of stalagmites is very different. It depends on the humidity of the air in the cave, the characteristics of its circulation, the magnitude of the influx of the solution, the degree of its concentration and the temperature regime. As observations have shown, the growth rate of stalagmites varies from tenths to several millimeters per year. Of particular interest in this respect are the works of Czechoslovak researchers who used the radiocarbon method to determine the age of karst formations. It has been established that the growth rate of stalagmites in the caves of Czechoslovakia is 0.5-4.5 cm per 100 years (G. Franke). In a long and complex history of the formation of sinter formations, epochs of material accumulation may alternate with periods of its dissolution.

Calcite sinter formations are characterized by the phenomenon of luminescence, which is associated with the presence of activating impurities in them. Sinter formations irradiated with a flash lamp glow with yellow, pale green, azure blue and blue light. Sometimes they emit a dazzling white even light that seems to flow from these fabulously beautiful shapes. The brightest luminescence has streaks with an admixture of manganese.

TO colomorphic formations include calcite dams (gurs), calcite crust, calcite films, cave pearls (oolites) and stone milk. The gours and cave ooliths, composed mainly of tuff, differ somewhat in structure, porosity, and bulk density from other sinter formations, which makes it possible to distinguish them into a separate group. However, this division is largely conditional.

Calcite dams, or gours, which spring up underground lakes, are quite widespread. In the Soviet Union, they are noted in 54 caves. Gura are found mainly in limestone and much less frequently in dolomite cavities. They are formed in horizontal and inclined passages as a result of precipitation of calcium carbonate from the solution, which is associated with the release of carbon dioxide due to changes in the temperature of the water flow as it moves through the underground gallery. The outlines of the dams, which usually have the form of a regular or curved arc, are determined mainly by the initial shape of the protrusions of the floor of the cave. The height of the barrages varies from 0.05 to 7 m, and the length reaches 15 m. According to morphological features, the gures are divided into areal and linear. The latter are developed mainly in narrow passages with underground streams, which they divide into separate reservoirs up to 1000 m2 or more in area.

The water flow not only creates calcite dams, but also destroys them. With a change in the flow rate and mineralization of groundwater, under the influence of erosion and corrosion, holes, breaks and cuts are formed in the gurs. This leads to the formation of dry gours, unable to hold water. As a result of further dissolution and erosion, only heavily corroded protrusions remain in place of the calcite dams, which are noted on the floor and walls of the cavity. According to the thickness of the seasonal semi-layer (0.1 mm), V. N. Dublyansky determined the age of the gours in the Red Cave. It turned out to be approximately 9-10 thousand years.

Calcite dams are especially interesting in the caves of Krasnaya, Shakuranskaya and Kutukskaya IV. In the far part of the Red Cave, 36 calcite cascades with a height of 2 to 7 m and a length of up to 13 m were noted over a distance of 340 m. Their width sometimes reaches 6 m. the bed of the underground stream is blocked by 34 dams made of milky white calcite. Their height reaches 2 m, and their length is 15 m. The so-called sealed gours (calcite chambers) have been found here. The reservoirs dammed by them are completely covered with a calcite film. One of the passages of the Shakuran cave (Caucasus), whose length reaches 400 m, is divided by calcite dams into 18 lakes with a depth of 0.5 to 2 m.

The calcite crust usually forms at the base of the walls, along which the water seeping into the cave flows. Its surface, as a rule, is uneven, bumpy, sometimes resembling wave ripples. The thickness of the calcite crust in some cases exceeds 0.5 m.

On the surface of underground lakes with highly mineralized water, white calcite films are sometimes noted. They are formed from calcite crystals that float freely on the surface of the water. Soldering with each other, these crystals first form a thin film floating on the surface of the water in the form of separate spots, and then a continuous film of calcite covering the entire lake, like an ice cover. On lakes dammed by gourami, the formation of a film begins from the shores. Gradually growing, the film occupies the entire water surface. Film thickness is small. It varies from a few tenths of a millimeter to 0.5 cm or more. If the level of the lake drops, then a space can form between the surface of the water and the film. Calcite films are predominantly seasonal. They occur during dry periods, when a high concentration of calcium and hydrocarbonate ions is observed in lake water. When abundant rain and melt snow water enters the cave, calcite films on the surface of underground lakes are destroyed.

According to L. S. Kuznetsova and P. N. Chirvinsky (1951), the calcite film is a mosaic of grains 0.05–0.1 mm in diameter. The orientation of the grains is random. According to the nature of the color, they are divided into two groups. Some, brownish and cloudy, are slightly translucent, while others, colorless, more transparent, seem fibrous. As for the mineralogical composition, both groups of grains are represented by pure calcium carbonate. The upper surface of the crust under the microscope is bumpy, and the lower one is completely smooth.

Along with calcite films, gypsum films are also found on the surface of lakes. They, like transparent ice, cover not only the water surface of the lake, but also its clay shores. Such a film can be seen, in particular, on the surface of the lakes of the Kungur ice cave.

In many caves developed in carbonate rocks, small calcite balls are found, which are called oolites, or cave pearls. Pearls are oval, elliptical, spherical, polyhedral or irregular in shape. Their length usually varies from 5 to 14 mm, and their width - from 5 to 11 mm. The largest oolite in the Soviet Union was found in the Manikvar mine, which is part of the Anakopia cave system. Its length is 59 mm. In shape and size, it resembled a chicken egg. Flattened pearls predominate. Sometimes they are cemented in several pieces (10-20) and form an oolitic conglomerate. The color of the oolites is white or yellowish. Their surface is matte, smooth or rough.

Cave pearls are composed mainly (up to 93%) of calcite. In section, it has a concentric structure, with alternating light and dark layers. The thickness of the layers can be different. In the central part of the pearl, grains of quartz, calcite or lumps of clay are noted, around which shells of colloidal calcium carbonate grow. Interestingly, the crystalline shells of the oolites are separated from each other by thin layers of pelitomorphic limestone.

Cave pearls are formed in shallow underground lakes, which are fed by drops of water saturated with calcium carbonate dripping from the ceiling. An important condition for the formation of oolites is their continuous rotation. As the aggregates grow, their rotation slows down, and then stops altogether, since they completely fill the bath in which they are formed.

The growth of oolites depends on many factors. Under favorable conditions, they form very quickly (in the Postoino Cave in Yugoslavia in about 50 years). In the Khralupa cave (Bulgaria), ooliths 5-6 mm in diameter were found, which consisted of only 3-4 concentric layers. Therefore, their age can be determined at 3-4 years. However, the possibility of using calcite layering to determine the age of chemogenic formations should be treated with great caution, since "... the frequency of calcium carbonate deposition does not coincide with the seasons, but is determined only by changes in the amount of incoming water, its temperature and the surrounding air."

Cave pearls found in the Soviet Union in the caves of Divya, Kizelovskaya, Krasnaya, Anakopiya, Shakuranskaya, Vakhushti, Makrushinskaya and some others do not differ in chemical composition from the biogenic pearls of sea mollusks, since both are composed of calcium carbonate. Meanwhile, real pearls differ from cave pearls by a pronounced mother-of-pearl luster, characteristic of aragonite, which is represented by biogenic pearls. . Aragonite, however, is an unstable modification of calcium carbonate and spontaneously transforms into calcite. True, at ordinary temperature this transformation proceeds rather slowly.

Among the calcareous formations, lunar or stone milk, which is a typical colloid, is of particular interest. It covers the vaults and walls of caves in areas where water protrudes from narrow cracks and, under conditions of weak evaporation, strongly liquefies the rock, which in appearance resembles lime dough, creamy mass or white stone milk. This very rare and as yet unsolved phenomenon of nature has been noted in Krasnaya (Crimea), Kizelovskaya (Urals), Anakopiya (Caucasus) and some other caves of the Soviet Union.

On the walls and ceiling of some caves there are crystals of various autochthonous minerals: calcite, aragonite, gypsum and halite. Among crystallite formations especially interesting are calcite, aragonite and gypsum flowers (anthodites) in the form of bunches and rosettes of crystals, sometimes reaching several centimeters in length. Currently, they are found exclusively in dry areas of caves. Their origin is obviously connected, on the one hand, with the crystallization of carbonate of condensation drops, and, on the other hand, with the corrosion of karst rocks by condensation waters. Studies have shown that these are predominantly ancient formations. They were formed in hydrological and microclimatic conditions different from the present ones. There are also modern forms.

Along with anthodites, brushes of calcite, aragonite, gypsum, and halite crystals covering large areas of the walls and ceiling of the caves are of interest. Such crystal galleries have been noted in many underground cavities of the USSR (Kryvchenskaya, Krasnaya, Divya, etc.).

The main patterns of the formation of chemogenic deposits and the features of the crystallization accumulation of caves on the example of the Anakopia abyss were studied by V. I. Stepanov (1971). In his opinion, the general course of crystallization of each individual section of this cave follows the scheme: tuff stalactite-stalagmite crust - calcite stalactite-stalagmite crust - corallites - gypsum.

The most detailed scheme of speleolithogenesis was developed by G. A. Maksimovich (1965). He showed that the nature and morphology of chemogenic formations depend on the amount of water inflow and the partial pressure of carbon dioxide, which change significantly at different stages of cave development. With large inflows of water (1-0.1 l / s), calcium carbonate falling out of the solution forms covers and gures on the floor of the cave (Fig. 7). The latter are often arranged in cascades. When the inflow of water from cracks and holes in the ceiling of the cave decreases, conditions are created for the formation of massive (0.01-0.001 l/sec), pagoda-like (0.001-0.005 l/sec) and palm trees (0.005-0.0001 l/sec) stalagmites. With a further decrease in the influx of water saturated with calcium carbonate, first conical stalactites (10 -4 -10 -5 l / s) appear, and then stick stalagmites (10 -5 -10 -6 l / s). Of particular interest is the class of tributaries with a flow rate of 10 -4 -10 -5 l/sec (or 0.1-0.01 cm 3 /sec), which determine the transition from the lower to the upper litho-accumulation, as well as their joint development. With negligible water inflows, tubular stalactites (10 -3 -10 -5 cm 3 / sec), complex stalactites with a wide base (10 -5 -10 -6 cm 3 / sec) and eccentric stalactites (10 -6 -10 - 7 cm 3 /sec). Condensation waters also take part in the formation of eccentric stalactites. At this stage of speleolithogenesis, the forces of crystallization dominate over the force of gravity, which played a major role with more significant inflows. The final link in the genetic series of chemogenic formations are crystallite forms associated with the precipitation of calcite from condensation waters, which at this stage represent the only source of moisture.

The scheme for the formation of speleoforms proposed by G. A. Maksimovich (1965) is of great theoretical and methodological significance. It allows us to outline a harmonious genetic series of carbonate lithogenesis of caves, based on the quantitative indicators of groundwater runoff and partial pressure of carbon dioxide, the change of which over time is associated with the stages of development of karst cavities. In this scheme, unfortunately, the position of many widespread sinter forms (columns, curtains, draperies, etc.) is not determined, which is due, on the one hand, to the limited material of experimental observations, and on the other hand, to the general poor development of the problem under consideration.

Chemogenic or water-chemogenic formations, which make many caves unusually beautiful, are just one of the types of cave deposits. In addition to them, in the caves (according to the classification of D.S. Sokolov and G.A. Maksimovich) there are also various other deposits, which are divided by origin into residual, water-mechanical, landslide, glaciogenic, organogenic, hydrothermal and anthropogenic.

Residual deposits are formed as a result of leaching of karst rocks and accumulation at the bottom of the caves of an insoluble residue, represented mainly by clay particles. Cave clays are best studied in the dry galleries of the Anakoli cave, where they reach a thickness of 0.45 m. The upper part of the residual clay sequence consists mainly of fine particles, while the lower part consists of uneven-grained ones. The composition of these clays is dominated (more than 63%) by particles ranging in size from 0.1 to 0.01 mm (Table 1).

Water-mechanical deposits are represented by alluvium from underground rivers, sediments from cave lakes, and allochthonous material brought into caves through cracks, organ pipes, and wells. They are composed of sandy-clayey material. The thickness of these deposits is usually small. Only under the organ pipes do they form clay scree, sometimes having the form of pointed cones up to 3 m high or more.

Particularly interesting are the plastic clays of the Anakopia cave, which occupy an area of ​​more than 10,000 m 2 . They cover the floor of the Clay Grotto and most of the grottoes of Abkhazia and Georgian Speleologists. Presumably, the thickness of these clays reaches 30 m. Plastic clays are formed mainly by the smallest particles with a diameter of less than 0.01 mm, which account for over 53%. They have an aleurite-pelitic structure and are usually colored by hydrous iron oxides. These clays were formed as a result of the sedimentation of fine particles at the bottom of temporary reservoirs formed in the southern part of the cave, due to the penetration of atmospheric precipitation, which is characterized by significant turbidity. The periodicity and duration of accumulation of plastic clays are confirmed by the presence of various horizons in them.

landslide deposits They usually consist of large chaotically piled up blocks of rocks that have collapsed from the vaults and walls of underground cavities. Interesting calculations in this regard were made in the Anakopia cave. They showed that the volume of collapsed material in the grottoes Khram, Abkhazia and Georgian Speleologists is approximately 450 thousand m 3 (i.e., more than 1 million tons of rock), and the volume of individual blocks reaches 8-12 m 3 . Thick block piles are also noted in many other caves (Fig. 8).

Among blocky-landslide deposits, fragments of calcite sinter formations (stalactites, stalagmites) associated with the collapse of the vaults are often found.

Most often, old landslide deposits are observed, covered with clay and calcite incrustations. However, in some caves you can also find completely fresh landslides. Such areas were studied by us, in particular, in the Divya (Ural) and Kulogorskaya (Kuloi plateau) caves.

Glaciogenic deposits. In many caves of the Soviet Union, where negative temperatures prevail throughout the year, ice formations are noted. The most famous ice caves are Kungurskaya, Kulogorskaya, Balaganskaya and Abogydzhe.

Cave ice of karst cavities - glaciers, widespread in the Crimea, the Caucasus, the Russian Plain, the Urals and Central Siberia, are divided into the following main types: sublimation, infiltration, congelation and heterogeneous.

Among sublimation formations Of greatest interest are ice crystals, which form as a result of the interaction of relatively warm air with chilled objects. They have the most diverse form, which is determined by the temperature regime, humidity, direction and speed of air flows (Dorofeev, 1969). There are leaf-shaped crystals (formed at a temperature of -0.5-2 °), pyramidal (-2-5 °), rectangular-lamellar (-5-7 °), needle-shaped (-10-15 °) and fern-shaped (-18 -20°). The most beautiful are pyramidal crystals, usually represented by intergrowths of spiral pyramids up to 15 cm in diameter. Occasionally, relatively regular closed six-sided pyramids appear on the vaults of caves, with their tops facing the ceiling. Fern-like crystals are also beautiful, which form in severe frosts and look like thin (0.025 mm) plates up to 5 cm long, hanging in a thick fringe from the ceiling of the caves. These crystals are ephemeral; at a slight increase in temperature, they are destroyed. Growing together, crystals often form sparkling garlands, openwork lace and transparent curtains. Ice crystals are transparent and very fragile. When touched, they crumble into small pieces, which slowly fall to the floor of the cave.

Ice crystals usually appear in the spring and last for several months. Only in some caves, especially those located in the area of ​​permafrost, are perennial crystals found. The chemical composition of ice crystals depends on the composition of the rocks. According to E. P. Dorofeev (1969), the mineralization of annual sublimation ice crystals in the Kungur cave is 56-90 mg/l, and perennial - 170 mg/l.

TO filtration forms include ice stalactites, stalagmites and stalagnates of hydrogenous origin. They are formed as a result of the transition of water into a solid phase. These forms reach 10 m in height and 3 m in diameter. Their age varies from 2-3 months to several years. In the Kungur cave, for example, there is an ice stalagmite that is over 100 years old. Annual forms are transparent, and perennial forms, due to impurities, have a milky white color with a bluish or greenish tint.

Annual and perennial ice formations also differ from each other in structure. As studies by M.P. Golovkov (1939) showed, annual stalactites in the Kungur cave are an optically uniaxial single crystal, while perennial stalactites consist of many, layer-by-layer, elongated, partially faceted crystals oriented with optical axes parallel to the length of the stalactite.

According to the chemical composition, the ice of stalactites, stalagmites and stalagnates can be fresh with the amount of soluble substances up to 0.1% (1 g / l) or brackish, in which soluble substances contain from 0.1 to 1%. Fresh ice is usually found in carbonate caves, and brackish - in sulfate.

On the walls and vaults in the cold part of some caves, an icing crust is noted, which is formed, on the one hand, due to the freezing of water flowing through cracks, and on the other hand, due to the sublimation of water vapor. Its thickness usually varies from fractions of a millimeter to 10-15 cm. The ice is transparent, sometimes milky white, fresh (soluble substances less than 1 g/l) or brackish. The age of the icing crust can be very different, in some cases many years.

Covering ice is often developed on the floor of grottoes and passages of ice caves. It is of hydrogen or heterogeneous origin. The thickness of the cover ice varies from a few centimeters to several meters. Multi-year, often layered ice prevails. Firn occurs in areas of snow accumulation. The chemical composition of cover ice depends on the composition of karst rocks. Distinguish between fresh and brackish ice. The latter in gypsum caves is characterized by a sulfate-calcium composition. The mineralization of cave ice reaches 0.21%. Of particular interest are the ice crystals formed on the floor of the caves when the infiltration waters solidify. They look like fused needles with plates growing from below.

Congelation ice is represented by ice of underground lakes and rivers. Lake ice forms on the surface of underground lakes in cold weather or throughout the year. The area of ​​lake ice depends on the size of the lake. In some cases, it reaches 500 m 2, and the ice thickness is 0.15 m (Lake of the Geographical Society in the Abogydzhe cave, on the Mai River). Ice on underground streams has a predominantly local distribution. The area of ​​river ice and its thickness are usually small. The origin of lake and river ice is hydrogenic. When underground reservoirs freeze, crystals are sometimes formed in the form of six-pointed stars 1 mm thick and up to 10 cm in diameter.

Cave ice contains various trace elements. Spectral analysis of cave ice taken from the icing crust in the Diamond Grotto of the Kungur Cave showed that strontium predominates among the microelements, accounting for more than 0.1%. The content of manganese, titanium, copper, aluminum and iron does not exceed 0.001%.

According to the conditions for the occurrence of cave cold, the accumulation of snow and ice, N. A. Gvozdetsky (1972) distinguishes seven types of karst ice caves in the Soviet Union: snow hole; b) cold bag-shaped caves, ice in them can form by freezing of water coming from cracks; c) through, or blowing, cold caves with the direction of air draft changing in warm and cold half-years, with hydrogenous ice and atmospheric, or sublimation, ice crystals; d) through horizontal glacier caves with a window in the ceiling through which snow enters, turning into ice; e) through, or blowing, caves - areas of permafrost, where cave ice is its special form; f) well-shaped cavities - areas of permafrost; g) bag-shaped cavities - areas of permafrost.

Organogenic deposits- guano and bone breccia are found in many caves of the Soviet Union. However, the phosphorite deposits of these caves are of considerable thickness and occupy relatively small areas. Large accumulations of guano were noted in the Bakharden cave, where they occupy an area of ​​1320 m 2 . The thickness of these deposits reaches 1.5 m, and the total reserve is 733 tons. As a result of the interaction of phosphate deposits of guano with carbonate rocks and calcite sinter formations, metasomatic phosphorites are formed.

hydrothermal deposits are relatively rare in karst caves. Of greatest interest in this regard are the caves in the upper reaches of the Magian River (Zerafshan Range), developed in the Upper Silurian limestones. They contain Icelandic spar, fluorite, quartz, antimonite, cinnabar and barite. The origin of these caves is associated with the action of hydrothermal solutions circulating through tectonic cracks. The formation and accumulation of mineral deposits in these caves occurred at later stages of their development.

Anthropogenic deposits in the caves are represented mainly by the remains of ancient material cultures, found mainly in the near parts of the caves. Recently, due to the frequent visits to caves by tourists and speleologists, various deposits of anthropogenic origin (food leftovers, paper, used electric batteries, etc.) accumulate in them.

In Europe and Asia, there are many prehistoric hominin sites with tools and other man-made objects, but the finds of the remains of ancient people are not very numerous. Researchers at the Max Planck Institute for Evolutionary Anthropology, in collaboration with a team of archaeologists and paleontologists, including renowned Russian archaeologist Anatoly Derevyanko, have found a way to "catch" tiny DNA fragments from a variety of mammals, including ancient humans, from cave deposits. About a new method that could revolutionize archeology, scientists told in the journal Science .

By studying the DNA of Neanderthals and Denisovans, researchers are recreating our own evolutionary history. However, fossil remains of ancient people are rare, and even those are not always suitable for genetic analysis.

“We know that some sediment components can bind DNA,” says Matthias Meyer, one of the researchers. “So we decided to find out if hominin DNA could be preserved in the sediments at the ancient sites where they lived.”

With this goal in mind, Meyer and other scientists teamed up with a host of researchers who excavated seven archaeological sites in Belgium, Croatia, France, Russia, and Spain. They collected sediment samples aged 14-550 thousand years. Using very little material, the researchers recovered and analyzed fragments of mitochondrial DNA and identified them as belonging to twelve different mammalian species, including the woolly mammoth, woolly rhinoceros, cave bear and cave hyena.

Deposit sample prepared for analysis

The team then went on to look directly at the samples for hominin DNA. “We suspected that most of our samples would have too much mammalian DNA to detect traces of human DNA,” said Dr. Vivian Slon, lead author of the study. “So we changed our strategy and targeted specifically human DNA fragments.” Researchers have developed a molecular "hook" from modern human DNA, with the help of which they "caught" sequences that are most similar to it. They were worried that hominin DNA would be so scarce that it could not be detected. “My jaw dropped,” Slon describes his emotions at the time of finding Neanderthal DNA. Enough hominin DNA for further analysis was isolated from nine samples. Eight of them contained mitochondrial DNA from one or more Neanderthals, and one from Denisovans.

“This is truly a revolutionary approach. If everything is really as cool as the article says, then paleoanthropologists should expect many discoveries in the near future, - shares his impressions with Gazeta.Ru, science popularizer and editor-in-chief of the Anthropogenesis.ru portal.

- In fact, the technology did not appear yesterday - this is what is called metagenomic analysis: when they take a sample from the environment and extract from it all the DNA that they find. For example, from water in a lake, or from bottom sediments, or from soil. In such a "metagenome" there may be DNA fragments of thousands of living beings - primarily microorganisms, but not only. With the help of specially designed procedures, experts determine who owned these "pieces of code."

“By extracting hominin DNA from sediments, we can get information about the presence of groups of hominins in places where it could not be detected in other ways,” says geneticist Svante Paabo. “This shows that DNA analysis of sediments is a very useful archaeological procedure that may become a common practice in the future.”

DNA was even isolated from samples that had been stored at room temperature for years. The analysis of these and other, more recent, samples will significantly deepen the existing knowledge about human evolution.

“Recently, they did this with Neanderthal tartar - and found out what animals and what plants they ate tens of thousands of years ago,” says Sokolov. “Now let’s go even further.

What gives such an approach? An opportunity to study monuments where there are no human remains at all. And after all such monuments the majority!

For example, there are many Middle Paleolithic sites on the Russian Plain, but there are almost no human remains. Therefore, strictly speaking, we do not know what kind of people they were. Probably Neanderthals - but what if not? A new approach will allow us to answer this question.”

One of the first systematic descriptions of cave deposits in Russia was given by A.A. Kruber in his famous monograph "The Karst Region of the Crimean Mountains" (Kruber, 1915), where, in accordance with the classification of E.A. Martel differ: sinter formations; tuff at groundwater outlets; products of destruction and shedding of walls; products of failures and collapse of vaults; cave clay - an insoluble residue of karst rocks; clastic deposits brought from the surface; as well as deposits of animal and vegetable origin; snow and ice.

The deposits of karst cavities are most often of Anthropogenic age. But in the classification constructions of Quaternary deposits, they are practically not taken into account (Kizevalter, 1985; Kozhevnikov, 1985; Shantser, 1966). There is currently no comprehensive classification of cave deposits. In the domestic literature, the classification of D.S. Sokolova - G.A. Maksimovich, which includes eight types of cave deposits (Maksimovich, 1963). Created in the early 60s of the last century, it subsequently, having undergone some changes, continues to be used to this day. We will also take as a basis this classification, widely known to speleologists, with the addition of the available data from modern research.

1. Residual deposits
Residual deposits are usually understood as deposits formed due to the insoluble residue of rocks enclosing cavities. Massive well karst limestones, in which many karst caves are laid, contain 1-5% of insoluble residue. Calculations show that when 1 m 3 of limestone dissolves, about 140 kg (0.05 m 3) of clay material is formed (Dublyansky, 1977; Shutov, 1971). For gypsum rocks in the area of ​​the Kungur cave, with a content of 1.6-2.3% of the insoluble residue, this figure is 70 kg per m 3 of sulfate rock. It is usually quite difficult to isolate a pure genetic type of residual deposits. These include brown-red plastic clays, which cover the inner surface of some domes and karst cracks with a thin layer. A few spectral analyzes indicate the presence of Be, Ba, Ti, V, Mn, Cr, Ni, Co, Pb, Sn, Ga, La in them in amounts not exceeding the content of these elements in the host rocks (Dublyansky, Polkanov, 1974; Stepanov , 1999).

The residual deposits probably include finely elutriated clays that make intricately curved depressions on the vaults and walls of the caves. These are “clay vermiculations”, which are the result of a combined impact on the rock of aggressive condensation waters and bacterial microflora capable of assimilating carbon from host limestones (Hill and Forti, 1997).

Residual deposits may cover the walls of cavities completely filled with water. When working with scuba, residual deposits are easily stirred up, which makes underwater speleological research difficult.

2. Landslide deposits
Collapse deposits are a widespread, but little studied type of cave deposits. V.N. Dublyansky (Dublyansky, 1977; Dublyansky, Dublyanskaya, 2004) identified four genetic subtypes of landslide deposits: thermo-gravity, landslide-gravity, failure-gravity, seismic-gravity.

Thermo-gravity deposits are formed in the inlet part of the cavities and are the result of physical weathering in the zone of sharp daily fluctuations in air temperature. Represented by crushed stone and gruss of limestone, they form seasonal interlayers in loose accumulations. Usually they are distributed only in the entrance parts of the caves. The thickness of thermogravitational deposits can reach several meters (Vorontsovskaya, Akhshtyrskaya, Partizanskaya, Atsinskaya, etc., Western Caucasus). The deepest layers are characterized by stronger weathering, in some places the fragments are destroyed to aluminous material. If they have a reddish color due to enrichment with iron and manganese oxides, then their formation occurred in a humid and hot climate. The overlying layers, as a rule, are represented by desquamated rubble with dark brown humus loams - the presence of such deposits indicates milder climatic conditions conducive to soil formation processes in a temperate climate. The upper layers are represented by fine gravel and light gray loam, which indicates a slowdown in the weathering process during the Holocene. Thus, the position and size of the fragments, the nature of their surfaces and faces, color, and the presence of secondary metal oxides make it possible to reconstruct the paleoclimatic conditions for the formation of karst cavities (Niyazov, 1983).

Collapse-gravity deposits represented exclusively by autochthonous material. They are formed throughout the caves as a result of the destruction of underground passages, forming colluvial accumulations mainly near their walls. Block accumulations, which are the largest in size of fragments, are characteristic of sections of cavities laid down in zones of tectonic faults. The size of clastic material depends on the layering of rocks, their jointing and the height of underground halls and galleries. Sometimes landslide-gravitational deposits are formed in the form of large colluvial cones at the base of karst mines. These deposits are practically unsorted, often compacted. They can form secondary sinter formations. The weathering of the inner surfaces of the open cavities is facilitated by the wide development of alterite in the near-wall zone, a rock altered as a result of metasomatic reactions during the interaction of pore and channel fluids (Klimchuk and Timokhina, 2011).

Failure-gravity deposits are formed when the vaults of caves or their individual floors fail. Large failure-gravitational deposits are known in all mountain-folded regions of the country. The most significant block accumulations are observed in areas close to the fault planes of tectonic faults. In the Marble Cave (Crimea) in the Perestroika Hall, the largest landslide limestone blocks reach a size of 20x6x3 m and weigh up to 1000 tons. in the upper reaches of the underground river), the weight of individual blocks reaches 2.5 thousand tons. Large failure-gravitational bodies are seismogenic in nature (Dublyansky, 1977; Dublyansky, Vakhrushev, Amelichev, Shutov, 2002). The failure-gravity deposits are also characterized by localization, poor sorting of clastic material, consisting of large blocks of various sizes, gruss and fine earth. The thickness of failure-gravitational deposits can reach hundreds of meters and a volume of thousands of m 3 .

Seismic gravity deposits are represented by collapsed interfloor ceilings of landslide halls, as well as fallen sinter columns and stalagmites taken out of a vertical position. Similar formations are often found in seismically active regions of Russia.

G.A. In 1943, Maksimovich singled out karst seisms in the group of denudation processes, which have a shallow hypocenter depth (30-100 m) and strength (no more than 6-7 points at the epicenter). Seismographs usually register them as negative arrivals.

There are quite a lot of references to karst seisms in the literature. Geologists A.A. Foreigners, P.N. Barbot de Marny, F.Yu. Levinson-Lessing considered all weak Crimean earthquakes to be failures. Calculations show that failures in the ceilings of the halls in the Red Cave can cause earthquakes with a magnitude of 2.5-2.7 units (3.7-3.9 points) in the nearest settlements (Simferopol - 22 km, Alushta - 26 km). In terms of released energy (n·10 12 -10 17 erg), the largest dips are 3 orders of magnitude smaller than the Yalta earthquake of 1927. Similar deposits are also described for Caucasian caves (Vakhrushev, Dublyansky, Amelichev, 2001).

Very interesting information about the strength and direction of seismic tremors is given by fallen sinter columns of large halls and galleries of cavities. The maximum weight of such columns reaches 150 tons, the length is 8-10 m, the diameter is up to 6 m. The azimuths of the lying columns in the caves indicate epicentral zones, the seismic events of which led to their overturning. New generation stalagmites growing on them make it possible to determine the age of the earthquake associated with their destruction.

3. Water mechanical deposits
Water mechanical deposits of caves consist of alluvial-proluvial deposits of temporary and permanent channel underground watercourses, sediments of out-of-channel lakes and detrital deposits introduced from the surface through cracks, wells, shafts and caves-ponors. These deposits contain a large and versatile information about the hydrogeology and paleogeography of cavities, which requires the use of special methods of granulometric and mineralogical analyzes (Niyazov, 1983). Materials concerning water mechanical deposits of caves are available in almost every publication devoted to karstogenic and non-karst cavities. Let us separately consider their particle size distribution, mineralogical features, and significance as an indicator of paleovelocities and paleoflows of underground flows. The materials given below were obtained during the study of the caves of the Caucasus and Crimea. A similar technique can be used in other regions of the country.

Grading. Aqueous mechanical deposits of concentrated flows are clearly divided into three groups: channel (I), siphon-channel (II) and siphon (III). Individual samples within these groups have individual differences, but in general their statistical characteristics are quite stable (Fig. 1).

Channel sediments are characterized by good sorting (1.91), as they were formed in a permanent water flow. They are characterized by the coarsest composition (50-90% sand-gravel fraction). 3-18% is pebbles, which is never observed in deposits of other groups. It is rarely possible to establish clear regularities in the distribution of channel sediments by size and degree of sorting downstream. A typical cumulative curve has a convex shape.

Siphon-channel deposits were formed due to the mixing of channel and siphon deposits during floods. They are characterized by average (2.20) sorting. The average particle diameter ranges from 8 to 1.7 mm. Particles larger than 1 mm make up 12-70%, which can be explained by the repeated transfer in different hydrological conditions. 50% of deposits are represented by coarse sandy particles 1-2 mm.

Rice. 1. Fields of channel (I), siphon-channel (II), siphon (III) deposits and typical cumulative curves (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002)

Siphon deposits are characterized by the best sorting (1.42). This is explained by the fact that each siphon channel has its own capacity, which determines the flow rate and the size of the particles carried out by it. At the outlet of the siphon channel, the material of a certain size is separated. On average, 90-95% is accounted for by particles of sand dimension. Particles with a diameter of more than 1 mm in this group are only 10-12%.

The given data are of significant paleogeographical interest, since the conditions of their formation can be determined from the granulometric composition of sandy-pebble deposits. To do this, you can use the Hülström-Burkhardt method (Niyazov, 1983), which makes it possible to determine the paleohydrological conditions (velocity and flow rate) of the water flows that formed them based on the data on the granulometric composition of water mechanical sediments. This method was used to establish the hydrological characteristics of water flows in caves, where it showed its good informative value. Thus, in the Geographical cave (Western Caucasus), the paleovelocity was 1-2 m/s, and the paleoflow rate was from 3 to 10 m3/s

Of great interest is the study of the distribution of water mechanical deposits along the vertical. To do this, it is necessary to lay a pit, which should open the entire section. In the section of the pit, alternating layers of sand, clay and gravel will be visible. The section needs to be somewhat generalized - sampling is carried out from ten-centimeter layers, sometimes including several layers of sand or clay.

Figure 2 clearly shows an increase in the size of the material with depth. If archaeological artifacts are found in layers lying on bedrock, then it becomes possible to determine the rate and time of formation of these deposits. The cumulative curves (Fig. 2) of the exposed deposits belong to groups II and III, i.e. these are sediments formed in a siphon trap and mixed with intermittently supplied channel sediments. An analysis of such a section reveals peaks during which the entry of channel alluvium into the siphon trap sharply increased. The flow velocity varied from 0.00-0.25 m/s (settlement of clay particles) to 1.0-1.5 m/s (deposition of pebbles and gravel).

Mineralogical composition of water-mechanical deposits. For these purposes, schlich analysis of samples taken at various points in the caves is carried out. The conditions for their selection are different. With a small volume of a natural trap (bath, rock or sill threshold, meander niche filler, etc.), it is completely cleaned up to the raft. With a large thickness or areal distribution of water mechanical deposits, the sample is taken as an average over the section or over the area by the quartering method. Three samples are large (10-12 kg) technological samples characterizing the mineralogical composition of individual sections of the cave.

The samples are washed to a gray concentrate (in this case, the loss of heavy minerals is about 15%). Gray concentrate is treated with bromoform. Light and heavy fractions are subjected to electromagnetic separation. The granulometric composition of the sample is determined by sieving an average 100-gram sample taken from the original sample. Mineralogical analysis is carried out in a conventional manner. Quantitative determination of minerals is performed under a binocular, counting first by magnetic and non-magnetic fractions, and then - in relation to the weight of all heavy minerals in the sample. About 300 grains are counted in each fraction. Sample reduction is performed by the lane method. The results of the analysis are expressed in weight percent, taking into account the specific gravity of minerals.

Rice. Fig. 2. Pit section (A) and cumulative curves of the layers exposed by it (B) (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002)

The mineral composition of water mechanical deposits of karst cavities is close to the mineral composition of the insoluble residue of the host rocks (Dublyansky, Polkanov, 1974). The light fraction is represented mainly by quartz and quartz-micaceous aggregates, iron hydroxides, and charred plant residues. There are also fragments of incrustations of shells and small bones of rodents. The heavy fraction of host limestones contains: cinnabar, pyrite, marcasite, fluorite, leucoxene, ilmenite, spinel, rutile, brookite, anatase, chromite, magnetite, iron hydroxides, zircon, disthene, sillimanite, tourmaline, pyroxene, mica, chlorite, hornblende , garnet, staurolite, moissanite, barite, apatite, staurolite, glauconite, corundum, epidote, gold, galena, sphalerite, carbonate apatite and others (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002).

The reasons for the mineral wealth of water mechanical deposits of caves are different. The main one is that they are a natural enriched concentrate (the yield of heavy fraction for limestones is usually much less than 1%, and for cave filler it reaches 5%). Therefore, the appearance in its composition of minerals that have not yet been found in the host rocks is associated with the incompleteness of our understanding of the accessory mineralization of the latter. In karst areas, where the upper reaches of permanent and temporary streams are located within non-karst rocks, mines and ponors located at their contact with limestones are literally overloaded with alluvial-proluvial deposits. As you move downstream, the roundness and degree of sorting of the material in the caves increases. As a rule, large boulders and pebbles do not form continuous accumulations, but accumulate in hydrodynamic traps (evorsion boilers, underground lakes or extensions of passages, etc.). Sometimes there are areas once completely filled with boulder-pebble materials. After their secondary flushing, clogging deposits remain in the walls of the wells. In the flooded caves of Russia, during floods, the transported debris can clog narrow channels, which causes changes in the direction of underground flow, erosion of water-mechanical deposits in some places and sedimentation in others. In some areas of such caves, where deposits are cut through by modern flows, modern underground terraces are formed, the study of which can be carried out by the method described above. Caves located in the valleys of large rivers, the entrance to which is (or was) at the level of a high floodplain, can be flooded during floods. In such caves there are pebbles and boulders brought into the cave during a flood from a river channel (Shakuranskaya, Western Caucasus, etc.).

In some caves, dense, heavy dark brown nodules with a shiny outer crust can be found on the floor. In places, these nodules are cemented by carbonate material and form a kind of microconglomerate. The study of the samples in reflected light showed that they are composed of goethite and hydrogoethite.

4. Water chemogenic deposits
According to G.A. Maksimovich (Maksimovich, 1963), water chemogenic deposits are subdivided into sinter (subterranean), calcite (subaqueous), crystals of autochthonous minerals, and correlated deposits on the surface. The materials of the monograph by C. Hill and P. Forti (Hill, Forti, 1997) significantly changed the idea of ​​the formation of chemogenic cave deposits: a new concept of "speleothem" (secondary mineral formations formed in the cave environment as a result of physical and chemical reactions) was introduced; the number of described minerals increased from 40 (1950-1995) to 240; By composition, all the minerals of the caves were combined into 13 groups: native elements, sulfides, oxides and hydroxides, halides, arsenates, borates, carbonates, nitrites, phosphates, silicates, sulfates, vanadates, minerals of organic origin. The list of hydrothermal and ore minerals has reached more than 30 items for the former and 60 for the latter. The deposits of caves that have arisen in the process of volcanic activity are given - lava corallites and helictites; stalactites and stalagmites formed from clay and sand; a number of other rare forms of cave sedimentogenesis are also considered. In the domestic literature, there are already developments that take into account this classification, especially in the section describing cave mineral formation (Turchinov, 1996). Considering the complexity of the above classification, we will focus here on the first classification, the best known to domestic speleologists.

subterranean deposits. The type of subterranean formations (arising in the air, above contact with the water surface) includes stalactites, fringes, curtains, helictites, stalagmites, stalagnates, covers, shields, corallites, lime (moon) milk, etc.

stalactites widely distributed in karst caves. Occasionally they are also found in cavities of a different genesis, where they have not only a carbonate composition, but are also composed of mineral types of ferruginous-magnesian, sulfide, organogenic, and other compositions. There are stalactites from thin (2-4 mm) tubes 0.2-1.0 m long to various conical shapes with a diameter of 50-60 cm and a length of up to 4-5 m. When the central channel is blocked, stalactites acquire an oval semicircular section. The density of stalactites (the number per 1 m 2) in some parts of the caves reaches 20-30 pieces. Often they are arranged in rows, marking faults with sufficient water inflows. Stalactites grow from the arches of cavities, obeying the vector of gravitational forces. The main factor in the formation of stalactites and many other carbonate chemogenic deposits is the "discharge" of calcium carbonate at the geochemical barrier due to the difference in the content of CO 2 in the solution entering the stalactite and in the air of the cave.

stalagmites are formed on the floor of caves, ledges of walls and cave deposits. They are formed as a result of CO 2 degassing when water drops hit the floor of the cave. Stalagmites in karstogenic caves can be represented by all varieties described in the literature: stick stalagmites 2-3 m in diameter and up to 3 m high; conical, cylindrical and pagoda-shaped with a diameter of 5-80 cm and a height of up to 4-5 m; palm trees up to 20 cm in diameter and up to 3 m high; stalagmites of irregular shape, reaching 2-3 m in diameter and 4-6 m high. Often stalagmites also trace large cracks in the vault, from where water flows, located in one or more straight lines.

Stalagnates or columns are formed by the closure of large stalactites and stalagmites, located at the base of large water-abundant cracks. They can reach 12-18 m in height and up to 5-6 m in diameter and weigh 130-1100 tons. Sometimes overgrown stalagnates can divide large cave galleries into a number of isolated halls.

Sintered bark, integuments are formed when the solution enters from a horizontal crack or niche in the wall. They often form cascades of streaks, reaching a height of 20-30 m and a width of up to 30 m along the front. The surface of such covers is wavy, smooth, sometimes weathered. When water mechanical deposits are washed out from under the crust, “hanging crusts” appear, sometimes located at a considerable distance from each other. They are often characterized by layering, corroding, and ferruginization of individual layers.

Fringe And curtains are formed when water seeps out of a long crack or when it runs off along a ledge.

Calcite shields, drums and flags. They are relatively rare. The former are represented by round plates with a diameter of up to 1 m, sometimes more, bearing stalactites on the outer surface. The second look like a flag attached to the wall of the cavity. Their origin is debatable. Some researchers believe that these are the remains of calcite crusts that hung in the air after the clay substrate was washed out. It is more likely that they arose during the concentric growth of layers when fed from a capillary crack (Stepanov, 1999).

helictites- these are formations of complex morphology, formed on vaults, walls and on various subterranean deposits. In the zone of their growth, as a rule, there is no air movement. They grow in an arbitrary direction, bending at any angle, not obeying gravity. Apparently, crystallization forces are the main ones in their morphology. They are relatively rare.

corallites are formed during crystallization from water films of various (often aerosol) origin. They are found on vertical, inclined and horizontal surfaces of bedrock walls and sinter formations. In areas of annual flooding, they can be “armored” with a thin crust of manganese minerals and have a characteristic brown color. They are found both in areas with heavy traffic, and in areas with difficult air circulation.

Lime (moon) milk- these are curdled (in a waterlogged state) or mealy (in an air-dry state) formations covering walls and streaks. Rarely seen. They are a special form of film crystallization. From the surface, it consists of amorphous calcite grains pierced by a web of thin (0.1-0.05 microns) calcined threads, possibly of organic origin. The interior is amorphous. The consistency is usually creamy. When dried, it turns into a floury substance.

Antholites- stone flowers. They grow at the base, stretching out from the parent rock. They are formed only by highly soluble minerals (gypsum, epsomite, thenardite, saltpeter). One free crystal grows from each supply pore. It can grow together with other crystals or curl up in a complex arc.

Subwater deposits. They form below the water level or at the contact of the water surface with air.

In cavities completely filled with water, single crystals or their druses may appear. Minerals of the hydrothermal series are deposited in hydrothermokarst caves: sphalerite, quartz, calcite, pyrite, galena, cinnabar, fluorite, aragonite, barite, chalkozine, minerals of the uranium-thorium group, minerals of rare and precious metals, etc. Ore deposits can appear in these caves. Hydrothermal caves, completely flooded with water, are characterized by the growth of crystals, often columnar in shape, over the entire surface of the walls. For cold caves, crystal formation is confined to its individual parts.

Most often in speleological practice, one has to deal with cavities partially filled with water. Subaqueous deposits are represented by calcite films and shores, frames, gourami, cave pearls, etc.

Calcite films occur on the surface of the water of underground lakes. They arise as a result of crystallization on the surface of underground lakes during gas exchange with the atmosphere of the cave. They form the thinnest films that hold on the water by surface tension. They are found in both carbonate and sulfate caves. In slow-flowing lakes, they can form so-called "sealed gours", completely covered from above by a calcite crust. Calcite films consisting of calcium carbonate (97%) and clay particles (3%) can form on the surface of ice stalactites, stalagmites, near-wall ice streams (Druzhba Cave, Ural).

Calcite frames(zaberezh) are formed when the film adjoins the shore or to a stalactite, stalagmite. Widespread in the Crimean caves. They are formed on the sides of slow-flowing and stagnant lakes due to a decrease in their level. On the stalactites hanging into the lake, and on the stalagmites rising from the bottom, lacy rims of various shapes and sizes appear. In karstology, they are considered mineral indicators of the level of cave flooding.

Calcite dams (gurs) are widespread in many karst regions of Russia. The height of their dams varies widely from 0.2 to 7.0 m, the area of ​​lakes behind the gourami ranges from 2 to 200 m 2 . The deposition of calcite occurs due to a change in the hydrochemical balance of the flow near the complex thermogeochemical and hydrophysical barrier that occurs when water flows from the pool down the dam. A thin layer of precipitated calcite forms here. Gur, formed with a water inflow of 0.001-0.100 l / s, are located alone or in small groups at the base of large filter cracks, in areas of areal infiltration or condensation drops, in the narrowing of lateral tributaries, inaccessible for further passage. They are characterized by significant fluctuations in the height of leakage dams (0.5-5.0 m) and the area of ​​lakes behind them (0.2-15.0 m 2), a small length of dams (0.2-1.2 m), strong convexity of their walls downstream. The walls of the dams are composed of porous carbonate material (density 2.2-2.4 g/cm 3 ) and framed on the inside with calcite rims. At their bottom, there are frequent accumulations of bones of bats and small rodents, fragments of stalactites, and calcite pisoliths. Pebbles of host rocks are usually absent. Calcite dams are usually kept intact, and lakes overflow with water only after rains and snowmelt. Such guras are formed near the complex mechanical-thermodynamic barrier (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002).

The gours formed under flowing conditions with a water inflow of 0.1-100.0 l/s differ sharply from those described in morphology. Some of the dams of the Red Cave in Crimea consist of almost 11,000 seasonal layers. They are characterized by a significant height (0.2-7.0 m), a large area of ​​dammed lakes (10-200 m 2), a large length (usually 3-4 m, maximum - 13 m). The dams have a complex stepped profile with a predominance of vertical sections. They are composed of denser carbonate material (bulk weight 2.4-2.6 g/cm3). The inner and especially the outer walls of the dams are polished with water, and sometimes "armored" with a dense, shiny carbonate-manganese coating 0.2-0.3 mm thick. On the bottoms of dammed lakes of this type, there is well-rounded gravel and sandy-pebble material of autochthonous (enclosing limestones and incrustations) and allochthonous (quartz pebbles) origin. Gur can form cascades located downstream. Gur cascades are known in many karst cavities. A characteristic feature of the flowing gures is their breakthrough with an increase in water cut. For example, in the Red Cave, only 16% of all ghurs hold water. The rest of the dams are broken, and in 45% of cases this is a narrow (10-30 cm) cut, in 35% - this is a breakthrough of the wall of the evorsion boiler in the body of the dam, in 20% - a breakthrough of the base of the gur with the formation of an accumulative bridge at a height of 0.2 -2.1 m above the modern watercourse.

Calcite oolites and pisoliths they are found in shallow low-flowing lakes, in small depressions formed by drops falling from stalactites or cave vaults, in gour lakes, etc. Oolites and pisoliths differ only in size. Their rounded white differences are called cave pearls. Oolites are oval in shape with an average size of 5-10 mm.

An increase in water temperature in flow-through baths causes a decrease in the carbonate capacity of groundwater and, as a result, a more active formation of cave pearls.

Cave ooliths and pisoliths are formed by the central core and surrounding concentric layers. Pisolites are composed mainly of calcium carbonate. The dense core usually consists of fragments of limestone enclosing the caves, grains of quartz, less often - lumps of clay, pieces of tubular stalactites, small bird bones. The shape of the core determines the initial shape of the pisolites, sometimes remaining until the final stage. There are cases when, after an increase of 30-40 concentrations, the orientation of the large diameter of pisolite changes. This indicates its turn in the process of growth. The number of layers in the largest pisoliths reaches 180-200. In separate drying baths, pearls were found, broken by drying cracks. This indicates dehydration and "aging" of the original colloid clot. Thus, cave pearls are a polygenetic formation.

The chemical composition of oolites and pisoliths corresponds to the composition of the host limestones.

5. Crystals of autochthonous minerals
These include primarily calcite crystals in carbonate karst, gypsum in sulfate karst, and halite in hydrochloric karst. crystals Icelandic spar found in a number of karst cavities in the Crimea, the Caucasus, Central Asia, etc. As a rule, they are located in the widenings of cracks filled with yellow-brown clay. Crystals most often do not come into contact with the walls of the cavity. The average size of Icelandic spar crystals for the karst mine Hod konem (Crimea) is 8-10 cm, although individuals up to 15 cm long are also found here (Dublyansky, 1977). The crystals are transparent, colorless or light gray. The formation of Icelandic spar is associated with thermal waters.

Calcite crystals. In a number of caves of the carbonate karst of Russia, there are skeletal forms of calcite crystals ranging in size from a few millimeters to 5-7 cm. Large crystals have a pyramidal habit. Crystals of various sizes are frequent, the habit form of which is a scalenohedron. Obviously, they arose under subaerial conditions from cold solutions (temperature below 20°C).

In a number of karst cavities that have undergone a hydrothermokarst stage of their development, there are prepared calcite veins protruding above the surface of the walls. The surface of the vein calcite is corroded, locally covered with residual clay, manganese oxides, or carbonate incrustations. Calcite crystals faintly luminesce in light blue and blue colors. Spectral analysis revealed the presence of a number of elements in them: Ba, Na, Sn, Cu, Ni, Sr, B, Al, Si, Mn, Fe, Mg, Ti. The homogenization temperature of inclusions in them ranges from 40 to 120°C (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002).

Phreatic (subaqueous) calcite crystals can cover the walls of karst passages with a solid bark. They are composed of parallel columnar brown calcite crystals with a thickness of 5 to 60 cm. Their origin is associated with the hydrothermal stage of the origin of the cavities. There are solid inclusions of dolomite crystals, aggregates of barite-strontianite, hydroxyapatite, manganese hydroxides, antimonite, apatite and apatite-brushtite mineral metasomatic associations, etc. (Klimchuk and Timokhina, 2011).

gypsum crystals, although they are typical for sulfate karst, they are also quite common in carbonate karst, especially if the cave site is located near a tectonic fault, in a zone where only annual fluctuations in temperature and air humidity are noted, not exceeding 0.2 ° C and 0.3 mm rt. Art.

On karst rocks covered with clay, gypsum concretions of jagged shape grow, composed of coarse-grained gypsum. Gypsum crystals are usually prismatic, rarely retaining regular crystallographic outlines due to secondary dissolution. Gypsum flowers - antholiths - are formed in the areas where pore solutions enter. In carbonate karst, gypsum crystals are formed when infiltration waters act on pyrite scattered in limestones. They are a sign of the proximity of large fault zones.

6. Organogenic deposits
Organogenic deposits of caves are most often represented by phosphorites, guano, bone breccia, saltpeter, deposits of colonial microorganisms.

Guano and phosphorites of caves. Phosphorites and phosphorus-containing minerals are formed in karst cavities inhabited by terrestrial vertebrates. In many caves in Russia there are areas with deposits of bat guano. The mineralogy of phosphorus-bearing formations at the contact between guano and primary limestones is practically unknown. Meanwhile, more than 50 phosphates, including many rare minerals, have been described in the sediments of the Mira Caves (Hill and Forti, 1997).

bone deposits modern and more ancient eras in mass quantities are quite rare. Large accumulations of bones can form so-called bone breccias. In appearance, it is a loose sandy-argillaceous red-brown rock with a high content of oxides of phosphorus, silica, aluminum and iron. There are bony breccias cemented with carbonate. Sometimes there are pseudomorphs after fossil bone remains of the fauna of iron and manganese hydroxides, gypsum, calcite, carbonate apatite. Carbonate hydroxyapatite is described as a spherical shape up to 3-5 mm in size, yellow, amber-yellow, pinkish-white (Tishchenko, 2008). Archaeological and paleontological studies of the bones of various animals of ancient eras are an important material for paleogeographic reconstructions (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002; Bachinsky, 1970; Ridush, Vremir, 2008). Most often in the caves there are bone remains of a hare, deer, fox, cave bear, bull, hamster, mole rat, badger, dog, roe deer, horse, much less often - a cave lion, cave hyena, mammoth, hairy and Etruscan rhinoceros. Most of the bone remains are of Pleistocene age - up to 1.5 million years. Somewhat less common are Pliocene localities aged 2 or more Ma (Dublyansky, Vakhrushev, Amelichev, Shutov, 2002).

Saltpeter. Deposits of biogenic nitrate in the form of powdery deposits, crusts and small crystals are associated with the biochemical decomposition of nitrogen-containing organic substances in caves. They are known in the caves of the Crimea, the North Caucasus, Central Asia, Siberia, the Far East, etc.

7. Anthropogenic deposits
Anthropogenic deposits are traces of the life of modern and ancient man. Their studies make it possible to establish the nature of the use of each particular cave or artificial cavity (Dublyansky, Dublyanskaya, Lavrov, 2001). Archaeological studies of the karst regions of Russia have shown that the caves were used by ancient man, starting from the early Paleolithic. These materials are available in regional reports for almost every major karst region of the country.
A wide range of field and laboratory research methods are used to study cavity deposits. Quite extensive, mainly karstological, literature is devoted to their application (Niyazov, 1983; Dublyansky, Vakhrushev, Amelichev, Shutov, 2002, etc.).

Fig.3 Calcite rims at the level of standing water of an underground lake.
Fig.4. Calcite rims (zaberezh) of several levels of standing water of an underground lake




Fig.5. cascade drip
Fig.6. Calcite draperies and stalagmites of several generations




Fig.7. Cave hall with various sinter formations
Fig.8. Intergrown stalactites and stalagmites on calcite crust





Fig. 9 Crystals of celestine (strontium sulfate) against the background of white calcite incrustation (photo by L. Gomarev, A. Shelepin)
Fig.10. Helictites (photo by L. Gomarev, A. Shelepin)
Fig.11. Gypsum flowers - antholiths (photo L. Gomareva, A. Shelepin)

LIST OF USED LITERATURE

1. Andreichuk V.N. Systemic nature of the karst landscape // Speleology and karstology. - 2009. - No. 3. – S. 47-59.

Bachinsky GA Taphonomic characteristics of fossil vertebrates localities in karst caves of Ukraine // Physical geography and geomorphology (Karst of Ukraine). - 1970. - No. 4. - S. 153-159.

Vakhrushev B.A., Dublyansky V.N., Amelichev G.N. Karst of the Bzyb Range. Western Caucasus. - Moscow: RUDN, 2001. - 170 p.

Vakhrushev B.A. The role of geochemical transformations in karst geomorphogenesis // Speleology and karstology. - 2010. - No. 4. - S. 33-43.

Dublyansky V.N., Klimenko V.I., Vakhrushev B.A. Karst and underground waters of karst massifs of the Western Caucasus - L.: Nauka, 1985. - 150 p.

Dublyansky V.N. Karst caves and mines of the Crimean Mountains. - L.: Nauka, 1977. - 180 p.

Dublyansky V.N., Dublyanskaya G.N. Karstology. Part 1. General karst studies. - Perm: PGU, 2004. - 307 p.

Dublyansky V.N., Dublyanskaya G.N., Lavrov I.A. Classification, use and protection of underground spaces. - Yekaterinburg: Ural Branch of the Russian Academy of Sciences, 2001. - 195 p.

Dublyansky V.N., Polkanov Yu.A. The composition of aqueous chemogenic and mechanical deposits of karst cavities of the Mountainous Crimea // Caves. - Perm, 1974. - Issue. 14-15. - S. 32-38.

Kizevalter D.S., Ryzhova A.A. Fundamentals of Quaternary Geology. - M: Nauka, 1985. - 177 p.

Kozhevnikov A.V. Anthropogenic mountains and foothills. - M.: Nedra, 1985. - 181 p.

Kruber A. A. Karst region of the Crimean Mountains. - M., 1915. - 319 p.

Klimchuk A.B., Timokhina E.I. Morphogenetic analysis of the Taurskaya cave (Inner ridge of Piedmont Crimea) // Speleology and karstology. - 2011. - No. 6. - S. 36-52.

Dublyansky V.N., Vakhrushev B.A., Amelichev G.N., Shutov Yu.I. Red Cave. Experience of complex karstological research - M. : RUDN University, 2002. - 190 p.

Maksimovich G. A. Fundamentals of karst studies T. 1. - Perm: Perm book publishing house, 1963. - 444 p.

Problems of studying karst cavities in the southern regions of the USSR / ed. R. A. Niyazov. - Tashkent: Fan UzSSR, 1983. - 150 p.

Ridush B.T., Vremir M. Results and prospects of paleontological study of Crimean caves // Speleology and karstology. - 2008. - No. 1. - S. 85-93.

Stepanov V.I. Mineralogy of caves // Caves. - Perm, 1999. - S. 63-71.

Tishchenko A.I. Mineralogical study of the Crimean karst cavities // Speleology and karstology. - 2008. - No. 1. - P.81-84.

Turchinov II Genetic classification of cave minerals and speleomineral formations // Svet. - 1996. - No. 1 (14). - S. 24-26.

Shantser E.V. Essays on the doctrine of the genetic types of continental sedimentary formations. - M.: Nauka, 1966. - 239 p.

Shutov Yu.I. Formation conditions, hydrodynamic hydrochemical zonality of fissure-karst waters of the Main Ridge of the Crimean Mountains. Abstract of the dissertation for the degree of candidate of geological and mineralogical sciences. Kyiv, 1971. - 22 p.

2. Hill C.A., Forti P.Cave minerals of the World. - Huntsville, Alabama, U.S.A. - 1997. - 462 p.

3. CAVE DEPOSITS

Almost all sedimentary and crystalline formations known on the surface are present in the caves, but they are represented by specific forms.

1. Residual deposits. In karst rocks in small quantities (1 - 10%), an admixture of sand or clay is necessarily contained, consisting of SiO 2, Al 2 O 3, Fe 2 O 3. When limestone or gypsum dissolves, the insoluble residue accumulates on the walls of cracks and slides to the bottom of the galleries. Mixes with other cave deposits. For example, from 1 m³ of Jurassic limestone (about 2.7 tons), 140 kg of clay is formed, which is composed of minerals illite, montmorillonite, kaolinite, feldspar, quartz. The properties of clays depend on their ratio: some of them swell when moistened, clogging small cracks, while some, on the contrary, easily release water and quickly crumble from the walls. Sometimes bacteria also take part in the formation of clay plaques: some types of microbes are able to obtain carbon directly from limestone - this is how worm-shaped or rounded depressions (“clay vermiculations”) are formed on the walls.

2. Collapse deposits are divided into three groups of different origin.

- thermogravitational ones are formed only at the entrance to the cave, where daily and seasonal temperature fluctuations are large. Their walls “peel”, the crest part of the cavity grows, crushed stone and fine earth accumulate on the floor. The amount of this material, its composition, size, shape of particles, the number of their edges and faces store encrypted information about climate changes in the area for tens of thousands of years.

- landslide-gravitational deposits are formed throughout the caves, especially abundantly - in zones of tectonic fissuring. Crushed stone, gruss, small blocks that fell from the vaults give an idea of ​​the geological structure of the halls, which is difficult to study directly.

– failure-gravitational deposits: during a collapse at the bottom of the gallery, only the material that is available in the cave itself; when the vault fails, material from the surface enters it, and when the interfloor ceilings collapse, huge halls appear. These deposits are represented by blocks and blocks weighing hundreds of thousands of tons. The reddish-brown surface of the limestones is covered with white "stars" - traces of impacts of fallen stones. The limestones that make up the cave themselves fall at an angle of 30º, therefore, when a layer is torn off in the roof of the hall, it shifts pivotally, with rotation and overturn. In addition to blocks and boulders, there are fallen sinter columns. Strong earthquakes cause the vaults to collapse, and oriented fallen columns sometimes confidently point to the epicenters. Sinter columns are also “mineralogical” plumb lines, in which the position of the geophysical vertical of a given area is fixed throughout its entire growth. If, after falling, stalagmites or stalactites grow on them, then the age of the column can be determined by their age.

The feedback between karst and seismology is that when the cave roof collapses, blocks weighing up to 2-3 thousand tons are formed. Hitting the floor when falling from a height of 10–100 m releases energy equal to 1·! 0 13 - 10 15 erg, which is commensurate with the energy of earthquakes. It is localized in a small volume of rock, but can cause a noticeable local earthquake of up to 5 points.

3. Water mechanical deposits - a source of information about the conditions for the development of karst cavities. If the composition of the deposits corresponds to the composition of the minerals of the host rocks, then the cave was formed by local flows. The size of such deposits ranges from meter-long boulders (in caves formed by glaciers) to the finest clay. Knowing the cross-sectional area of ​​the passage and the diameters of the deposited particles, the velocity and flow rate of ancient flows are estimated, in which hydrodynamic zone the cave was laid.

4. water chemogenic deposits. The terms "stalactite" and "stalagmite" (from the Greek "stalagm" - a drop) were introduced into literature in 1655 by the Danish naturalist Olao Worm. These formations are associated with the drop form of water movement - a solution containing various components. When a solution drop forms at the base of a flooded fracture, it is not only a struggle between surface tension and gravity. At the same time, chemical processes begin, leading to the precipitation of microscopic particles of calcium carbonate at the contact of the solution and the rock. Several thousand drops that have fallen from the ceiling of the cave leave behind a thin translucent ring of calcite at the rock/solution contact. The next portions of water will already form droplets at the calcite/solution contact. Thus, an ever-elongating tube is formed from the ringlet (brchki - reach 4–5 m in the Gombasek cave, Slovakia). Thus, the chemical basis of the process is a reversible reaction

CaCO 3 + H 2 O + CO 2<=>Ca 2+ + 2HCO 3 - (1)

When limestone dissolves, the reaction proceeds to the right, with the formation of one divalent Ca ion and two monovalent HCO 3 ions. With the formation of sagging, the reaction goes to the left and the mineral calcite is formed from these ions. Reaction (1) proceeds in several stages. First, water interacts with carbon dioxide:

H 2 O + CO 2 \u003d H 2 CO 3<=>H + + HCO 3 - (2)

But carbonic acid is weak, therefore, it dissociates into a hydrogen ion H + and an ion HCO 3 - The hydrogen ion acidifies the solution, and only after that does the dissolution of calcite begin. In formula (1), only one HCO 3 ion comes from the rock, while the second is not associated with it and is formed from water and carbon dioxide introduced into the karst massif. This reduces the estimated activity of the karst process by 20–20%. For example, let the sum of all ions in water be 400 mg/l (including 200 mg/l HCO 3). If we use the analysis to evaluate drinking water, then all 400 mg / l are included in the calculation, but if the intensity of the karst process is calculated from this analysis, then the calculation should include the sum of ions minus half the content of the HCO 3 ion (400–100 = 300 mg / l). It is also necessary to take into account the difference in partial pressures of CO 2 present in the system. In 40-50 years. it was believed that the karst process is only due to CO 2 coming from the atmosphere. But in the air it is only 0.03–0.04 volume% (pressure 0.0003–0.0004 mm Hg), and fluctuations in this value in latitude and height above sea level are insignificant. But it has been noticed that caves of temperate latitudes and subtropics are richer in streaks, and there are very few of them in caves of high latitudes and high altitudes. The study of the composition of soil air showed that the content of CO2 in it is 1–5% by volume, i.e. 1.5–2 orders of magnitude greater than in the atmosphere. A hypothesis immediately arose: stalactites are formed by a difference in the partial pressure of CO 2 in the cracks (the same as in the soil air) and the air of the caves, which has an atmospheric content of CO 2 . Thus, stalactites are formed mainly not during the evaporation of moisture, but in the presence of a partial pressure gradient of CO 2 from 1–5% to 0.1–0.5% (air in caves). While the feeding channel of the stalactite is open, drops regularly flow through it. Breaking off its tip, they form a single stalagmite on the floor. This has been going on for tens or hundreds of years. When the supply channel becomes overgrown, clogged with clay or grains of sand, the hydrostatic pressure increases in it. The wall breaks through, and the stalactite continues to grow due to the flow of a film of solutions along the outside. When water seeps along the bedding planes and inclined cracks, rows of stalactites, fringes, curtains, and cascades appear in the roof. Depending on the constancy of the water inflow and the height of the hall, single stalagmites-sticks 1–2 m high (up to tens of meters) and 3–4 cm in diameter are formed under the droppers. 10–12 m. Under subaerial conditions (air), anthodites (flowers), bubbles (balloons), corals (coralloids, botryoids), helictites (spirals up to 2 m high), etc. are formed. Subaqueous forms have been noted. On the surface of underground lakes, a thin mineral film is formed, which can attach to the wall. If the water level fluctuates, rise levels are formed. In weakly flowing water, goura dams (from a few cm to 15 m high) and cave pearls are formed. The origin of only "moon milk" is still inexplicable.

Rice. 10. Geochemical conditions of formation of water chemogenic deposits of caves. Rocks and deposits: a – limestones, b – dolomites, c-gypsum, d – rock salt, e – ore body, f – clay, g – guano, h – soils; waters: i - soil, j - infiltration, l - thermal; m - classes of minerals (1 - ice, 2 - sulfates, 3 - nitrates, 4 - halides, 5 - phosphates, 6 - sulfur, 7 - carbonates, 8 - oxides, 9 - carbonate metals, 10 - sulfides); n - special conditions of formation (presence: 1 - pyrite, 2 - bacteria, 3 - colonies of bats, 4 - hydrothermal solutions, 5 - pyrite and marcasite); o - mineral species and forms of their isolation (1 - ice stalactites; 2 - epsomite, mirabilite, thenardite dendrites; 3 - epsomite and mirabilite crusts; 4 - gypsum, barite, celestine crystals; 5 - various calcite formations; 6 - moon milk; 7 - salt forms; 8 - hydrocalcite; 9 - aluminum phosphates; 10 - nitrophosphates; 11 - zinc and iron minerals; 12 - sulfide oxides; 13 - vanadinite, fluorite; 14 - iron and lead oxides; 15 - limonite, goethite; 16 - cerussite, azurite, malachite; 17 - opal stalactites; 18 - hemimorphite; 19 - quartz crystals)

5. Cryogenic. Water in the form of snow and ice is typical for caves with negative temperatures. Snow accumulations form only in underground cavities with large entrances. Snow flies into the cave or accumulates on the ledges of the mines. Sometimes snow cones with a volume of tens or hundreds of m³ are formed at a depth of 100–150 m under the inlet. Ice in caves has a different genesis. More often there is a compaction of snow, which turns into firn and glacier ice. Less often, an underground glacier is formed, even less often is the preservation of ice formed under permafrost conditions or the flow of ground glaciers. The second way of ice formation is the entry of melted snow water into cold (static) caves. The third way is air cooling in wind (dynamic) caves and the fourth way is the formation of sublimation crystals of atmospheric origin on a cooled rock surface or on ice. The least mineralized (30–60 g/l) is sublimation and glacier ice, the most (more than 2 g/l) is ice from gypsum and salt caves. Caves with ice are most often found in the mountains, at an altitude of 900 to 2000 m. Ice forms all the forms characteristic of ordinary sagging.

6. Organogenic: guano, bone breccia, phosphorites, saltpeter. There are also anthropogenic deposits.

7. Hydrothermal: anhydrite, aragonite, ankerite, barite, hematite, quartz, cinnabar, rutile. Also, some varieties of zonal calcite deposits are marble onyxes. Such formations have specific forms of excretion: often well-faceted crystals, intersecting partitions (boxworks), “geysermites” ... Known are karst deposits of lead and zinc, antimony and mercury, uranium and gold, barium and celestine, Icelandic spar and bauxite, nickel and manganese, iron and sulfur, malachite and diamonds.

Conclusion

Karst is very widespread on the surface of the Earth and in the near-surface zone of the earth's crust. An exceptionally great specificity and universality of karst forms and hydrological phenomena are observed. In most cases, the bath relief prevails on the surface of the Earth, with the exception of the remnant tropical karst (which is universal in itself), but in the tropics on the plains, the bath relief is quite widespread, moreover, it is often combined with the remnant. Karrs are not found in all types of karst, but as soon as the karst rock is exposed on the surface, they appear. Under various geological, geomorphological and physiographic conditions, karst forms are represented by unequal varieties, but the main types of forms and hydrological phenomena are evident everywhere. The universality of karst forms and hydrological phenomena is a consequence of the leading process in the formation of karst: the process of leaching of soluble rocks. The priority of the geological basis in the development of karst, karst relief and karst landscape can be emphasized. The development of karst is also influenced by the physical and geographical situation, which is associated with the latitudinal and altitudinal zonality of karst phenomena. The karst relief, karst landscapes and the processes taking place in them are so specific that not a single serious economic activity on a karst territory can be carried out without taking them into account and often without special study. Karst has a profound impact on the landscape as a physical-geographical complex. It affects the runoff, karst landforms - the microclimate and the distribution of soil and vegetation cover, karst rocks, their composition - soils and vegetation, the chemical composition of karst waters, the landscape as a whole, etc. The drainage capacity of karst enhances the lack of moisture in arid areas and, conversely, creates more favorable conditions for the development of landscapes in areas that are excessively moist. Karst leads to the degradation of permafrost, also significantly improving the natural features of the territory. The degree of influence of karst on the geographical landscape can be judged on the basis of the morphological and genetic type of karst.

Features of karst, often its morphological and genetic type and classification rank of the geographical landscape of the karst territory. The following taxonomic system of karst zoning can be proposed: karst country - region - province - district - district. Within the region, in a detailed study, it is recommended to identify typological units (areas of different types of karst), however...

PROCESSES As a result of karst-suffusion processes and phenomena, the stability of the geological environment decreases, which leads to catastrophic consequences (subsidences, failures, deformations of structures). In the Russian Federation, karst processes are widely developed in the Arkhangelsk, Leningrad, Moscow, Tula, Kursk, Nizhny Novgorod, Voronezh regions, the republics of Bashkortostan, Tatarstan, Mari El, Mordovia, ...

Sandstones with thin layers of gypsum), it can be assumed that favorable conditions for the formation of karst landforms have formed in the area under study. 1.3 Features of the tectonic structure of the Nyuksensky region The territory of the Nyuksensky region is located in the north-west of the Russian plate, which is characterized by a block structure of the crystalline basement. Lies within...

Thick-layered marbled limestones), and with the fact that a significant part of the sediments is confined precisely to the most elevated part of the peninsula. In the foothill and steppe parts of the Crimea, karst phenomena are also common, yet it is the leveled top surface of the Crimean Mountains (yayly) that is considered the classic area of ​​karst distribution. Karst within the Crimean Mountains...

Acquaintance with them also will not bring much pleasure to a non-specialist. There are lakes in the Red Cave, where you sink almost waist-deep into viscous clay, often leaving the soles of your shoes in it, or even the lower part of your wetsuit ... But the geologist sees in these deposits a source of various information about the conditions of the "life" of karst cavities. To obtain them, first of all, it is necessary to study the composition of the deposits.

Mineralogical analysis sometimes immediately gives an answer to the question of where the water comes from. If the composition of the deposits corresponds to the composition of the minerals of the host rocks, then the cave was formed by local, autochthonous flows. Therefore, back in 1958, just starting to explore the Red Cave, we already knew that its beginning should be sought on the plateau of the Dolgorukovsky massif, in the Proval mine, because only within the catchment area that feeds it there is quartz pebble. Studying the caves of the Koscielska valley in the Tatras, Polish speleologists noticed that the caves, located in the same place, but at different heights above the valley floor, had a different composition of sand filler: the closer to the bottom, the richer the range of minerals found in it.. The study of the region's paleogeography has shown that this is related to the depth of the river's incision, which gradually "reached" the watersheds of the central part of the Tatras, composed of non-karst rocks.

Of course, with detailed studies, this scheme looks much more complicated. Hundreds of samples have to be taken, divided into fractions by size, specific gravity, magnetic and other properties, the content of individual mineral grains has to be determined and counted under a microscope, etc. Amazing finds can be rewarded. Minerals were unexpectedly discovered in the Crimean caves: moissanite, cohenite, iocite, previously known only in meteorites; in the caves of Bulgaria, interlayers of volcanic ash were found, which there is reason to associate with the explosion of a volcano on the island of Santorin in the Aegean Sea in the 25th and 4th-1st millennia BC. e.

Thus, a thread was stretched connecting the explorers of the caves of the 20th century with the problems of Atlantis and the death of the Minoan culture...

The second line of research in water mechanical deposits is the study of their fineness. It can be different - from meter-long boulders, sometimes found in caves formed by glacial flows, to the finest clay, the particles of which are micron in size. Naturally, the methods of their research are also different: direct measurement, the use of a set of sieves, the use of conventional and ultracentrifuges. What do all these, often long and expensive, works give? The main thing is the restoration of the ancient paleogeographic conditions for the existence of caves. Between the speed of underground flows, the diameter of the channels through which they move, and the size of the particles carried, there are relationships that are expressed in rather complex formulas. They are based on the same Bernoulli flow continuity equations, "multiplied" by the equally well-known Stokes equation, which describes the rate of particle settling in stagnant water of different temperatures and densities. The result is a beautiful nomogram proposed by the Czech speleologist R. Burkhardt - a graph by which, knowing the cross-sectional area of ​​​​the passage and the diameters of the particles deposited on its bottom, one can estimate the average and maximum speed and flow rate of the streams that once raged here.

The study of aquatic mechanical deposits allows us to answer some theoretical problems, in particular the question of in which hydrodynamic zone this cave was laid. In 1942, having discovered thin clay at the bottom of a number of caves in the United States, an experienced geologist and speleologist J. Bretz suggested that they were formed by dissolving limestone with slowly flowing waters: after all, only in them is it possible for clay particles to settle! Fifteen years later, having dug deep pits in dozens of the same caves, Davis, a karst expert, established that fatty clays only crown a very complex multi-meter section of the aggregate. Under the clays there were layers of sand and gravel, brought by a powerful stream, then followed by a sintered crust, which could form only with prolonged drying of the cave, below - clay again appeared in the section, lying on the boulders ... This is how water mechanical deposits help specialists to "read" the history cave development.

Dublyansky V.N.,
non-fiction book