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Where is basalt used? Basalt rock

Magnetite etc.

Basalt- the main effusive rock of the normal series, the most common of all cainotype rocks. The main minerals of phenocrysts are clinopyroxene and calcium plagioclase (N 30-90), sometimes olivine, orthopyroxene; the groundmass is composed of the same minerals (without olivine) and magnetite in glass (or without it).

Name history

This mineral became basalt from the Latin basaltes, basanites, from the Greek. basanos - touchstone; according to another version, they became basalts from the Ethiopians. basal is an iron-bearing stone.

Classifications

Varieties can be distinguished according to the features of the mineral composition (apatite, graphite, diallag, magnetite, etc.), the composition of minerals (anorthite, labradorite, etc.), the features of the structure and (or) texture, chemical composition (ferruginous, ferrobasalts, calcareous, alkaline - calcareous, etc.).

Petrochemical classification

Yoder and Tilley (Yoder and Tilley, 1962) suggested using the nepheline-olivine-diopside-quartz tetrahedron for classification. The activity of silica in the melt is controlled mainly by reactions of the type:
2(Mg,Fe)SiO3 -> (Mg,Fe)2SiO4 + SiO2 (orthopyroxene = olivine + silica)
NaAlSi3O8 -> NaAlSiO4 + SiO2 (albite = nepheline + silica)

These reactions can be divided into 3 groups:

  • quartz-normative (containing excess silica)
  • nepheline-normative (lack of silica)
  • hypersthene-normative (in the absence of normative quartz or nepheline)

Membership in these groups is determined by chemical composition rocks, by the presence of the corresponding normative minerals in the results of petrochemical recalculation by the CIPW method.

Geodynamic classification

According to the geodynamic setting, the main types are distinguished:

  • Mid-ocean ridges MOR or MORB
  • Active continental margins and island arcs (IAB)
  • Intraplate, which can be subdivided into continental and oceanic (OIB).

Composition and structure

They are usually dark gray, black or greenish-black rocks with a glassy, ​​cryptocrystalline aphyric or porphyritic structure. Small phenocrysts of greenish-yellow isometric olivine crystals, light-colored plagioclase, or black pyroxene prisms are clearly visible in porphyritic varieties against the background of a common cryptocrystalline mass. The size of phenocrysts can reach several centimeters in length and make up to 20-25% of the rock mass. The texture in basalts can be dense massive, porous, amygdaloidal. Tonsils are usually filled with quartz, chalcedony, calcite, chlorite and other secondary minerals - such basalt is called mandelstein. The ground mass is often not crystallized. Aphyric (without porphyritic phenocrysts) varieties are frequent.

Basalt flows are characterized by columnar separation. It occurs as a result of uneven cooling of the rock. Marine basalts are often cushion-like. It is formed as a result of the rapid cooling of the surface of the lava flow by water. The incoming magma lifts the formed shell, flows out from under it and forms the next pillow.

Prevalence

Basalt is the most common effusive rock on Earth, and on other planets as well. The main mass in basalt is formed in the mid-ocean ridges and forms the oceanic crust. In addition, basalts are typical of settings for active continental margins, rifting, and within-slab magmatism.

During the crystallization of basaltic magma at a depth, strongly differentiated, layered intrusions (such as Norilsk, Bushveld and many others) are usually formed. They are composed of various rocks, the sequence of crystallization of which is determined by the dynamics of magma crystallization. First, the highest-temperature minerals crystallize from the melt, and they precipitate to the bottom of the magma chamber. in this case, the melt is enriched in some components and depleted in others. With a decrease in temperature, a change in crystallizing minerals occurs.

Layered massifs contain deposits of copper-nickel ores, chromites and platinoids.

Origin

Basalts are formed during the partial melting of typical mantle rocks - lherzolites, harzburgites, wehrlites, etc. The composition of the smelt is determined by the chemical and mineral composition of the protolith, the physicochemical conditions of melting, the degree of melting, and the mechanisms of melting.

Analogues

  • The hypabysal analog - dolerite is distinguished by a characteristic dolerite structure.
  • Intrusive analogs of basalt are gabbro, gabbro-norites, norites, troctolites.
  • Paleotype analogue of basalt - diabase

Changes

Basalts are very easily altered by hydrothermal processes. At the same time, plagioclase is replaced by sericite, olivine by serpentine, the groundmass is chloritized and, as a result, the rock acquires a greenish or bluish color. The basalts that pour out at the bottom of the seas change especially intensively. They actively interact with water, while many components are removed and deposited from them. This process is of great importance for the geochemical balance of some elements. So most of the manganese enters the ocean in this way. Interaction with water radically changes the composition of marine basalt. This influence can be estimated and used to reconstruct the conditions of ancient oceans from basalts.

metamorphism

During metamorphism in basalt, depending on the conditions, it turns into green shales, amphibolites and other metamorphic rocks. During the metamorphism of basalts at significant pressures, they turn into blue shales, and at high temperatures and pressures into eclogites consisting of pyrope and sodium clinopyroxene - omphacite.
Metamorphic rocks with a composition close to basalts are called metabasites.

Application of basalt

Basalt is used as a raw material for crushed stone, the production of basalt fiber (for the production of heat and sound insulating materials), stone casting and acid-resistant powder, as well as a filler for concrete. Basalt is highly resistant to weathering and therefore is often used for exterior decoration of buildings and for the manufacture of sculptures mounted on outdoors.

Rock Properties

  • Rock type: Igneous rock
  • Color: dark to black
  • Color 2: Black gray
  • Texture 2: porphyritic
  • Origin of name: from Latin basaltes, basanites, from Greek. basanos - touchstone; according to another version, from the Ethiopian. basal - iron stone
  • Structure: porphyritic
  • Texture: almond stone

Rock Photo

Rock deposits Basalt

  • Sinar
  • Evenk Autonomous Okrug
  • Russia
  • lacustrine

BASALT, a ceramic material with high mechanical, physical, electrical and chemical properties and obtained by thermal processing of rocks of the same name.

1. Basalt as a rock. Basalt, or rather basalts, are among the characteristic igneous (effusive) basic rocks of deep origin and young, predominantly Tertiary, age. Basalt gained its wide popularity for the picturesque fragments it forms in the form of 6-sided (and sometimes 3- or 5-sided) prisms 3-4 m long with planes perpendicular to the faces (Fig. 1); it is also found in the form of limestone natural stairs, shell-shaped spherical parts and other extremely picturesque rocks.

Basalt is a dark-colored rock, sometimes grayish-black, sometimes with a bluish tint; sometimes it is greenish or reddish. The very name "basalt" is of ancient origin and in the Ethiopian language means "dark", "black". This breed is very homogeneous in its fine build. Dense and extremely hard, it has graininess in different cases. different order. Coarse- and medium-grained varieties are called dolerites, fine-grained varieties are called anamesites, and very fine-grained varieties are called basalt proper. The difference in texture of basalt with identical bulk composition is explained by the conditions of solidification of igneous magma (cooling rate, pressure, etc.). The petrographic composition of basalt can vary significantly, but the minerals that make up the basalt are replaced by petrographic equivalents, as a result of which basalt as a rock retains its habitus very steadily. Under the microscope, basalt appears as a glassy groundmass (“basis”) with a microfluidic composition. The basis contains numerous crystals of feldspar, olivine, magnetic iron ore and other less typical minerals. Depending on the content of mineral inclusions cemented by the basis, basalts are distinguished: plagioclase, leucite, nepheline and melilite. Actually, it is customary to call the first basalt, that is, those containing calcareous-soda feldspar, augite and olivine. Basalt is chemically related to gabbro (G.) and diabase (D.). The bulk chemical analysis of plateau-forming basalt is characterized, according to Washington, by the following data:

Basalt is inherent in significant radioactivity: it contains from 0.46∙10 -3 to 1.52∙10 -3% of thorium and from 0.77∙10 -10 to 1.69∙10 -10% of radium. Less deep varieties of basalt are more acidic and gradually pass to dacites, trachytes, etc. According to the latest views, basalt is a material that forms a solid shell of the earth: under the continents 31 km thick, and under the oceans - from 6 km or more; this shell floats on a viscous-liquid underlying layer of basalt ("substrate"). Thus, it is assumed that basalt is everywhere. As for the very surface of the earth, the outcrops of this rock are very numerous. Outside the USSR, they are: in the Auvergne, along the banks of the Rhine, in Bohemia, Scotland and Ireland, on the island of Iceland, in the Andes, in the Antilles, on the island of St. Helena and in various other areas. There are many deposits of basalt in the northern, western and southeastern parts of Mongolia. Within the USSR, basalt is distributed in the Caucasus and Transcaucasia, as well as in northern Siberia, in the basin of the river. Vitim. In the near future, the following deposits may practically be of the greatest interest: Berestovetskoye - Volynsk district of the Ukrainian SSR, Isachkovsky - Poltava district of the Ukrainian SSR, Mariupol - Mariupol district of the Ukrainian SSR, Chiaturskoye, Beloklyuchinskoye, Manglisskoye and Saganlugskoye, Adjaris-Tskhalskoye - Georgian SSR, Erivanskoye - Armenian SSR, as well as Olonets diabase from the shores of Lake Onega.

2. Properties of natural basalt. The direct application of natural basalt and its further processing require sufficient knowledge of the mechanical, physical and chemical properties his. However, these properties are significantly related to the composition and texture of basalt and therefore vary significantly depending on the deposit. If we talk about basalt in general, then its properties can be. are characterized only by the limits of the corresponding constants. The data given below for basalt are partly compared with the data for diabase and gabbro. Apparent specific gravity(piece): 2.94-3.19 (B.), 3.00 (D.), 2.79-3.04 (G.). The true specific gravity (powder) is about 3.00 (B.). Porosity in % volume: 0.4-0.5 (B.), 0.2-1.2 (D.), 3.0 (G.). Water absorption: 0.2-0.4% by weight and 0.5-1.1% by volume (B.). The mass of 1 m 3 of dry basalt is about 3 tons. Compressive strength in kg / cm 2: 2000-3500 (B.), 1800-2700 (D.), 1000-1900 (G.). If the compressive strength of dry basalt is more than 3000, then wet basalt is more than 2500, and at a frost of 25 ° it is more than 2300. Wear strength (“hardness”, calculated by the formula: p \u003d 20-w / 3, where w is the mass, lost under normalized conditions at 1000 revolutions of the abrasive disk) is characterized by the numbers 18-19 (B., D., G.). Impact strength (“compactness”) when testing normalized samples: 6-30 (B., D.) and 8-22 (G.). Basalt is harder than steel. Young's modulus in (D cm -2) x10 -11 is 11 (G.) and 9.5 (D.). The volumetric compression ratio per 1 kg at a pressure of 2000 kg / cm 2 is 0.0000018 (B.) and 0.0000012 (D.), and at a pressure of 10000 kg / cm 2 it is 0.0000015 (B.) and 0.0000012 (D.). The beginning of melting of normal olivine basalt is at a temperature of about 1150°, and the liquid-melting state begins at a temperature of about 1200°. Molten rock ceases to be fluid when cooled to 1050°. More acidic rocks have a higher melting point, and it rises with the content of silicic acid. In particular, the basalt of the Adzharis-Tskhali deposit (dacite-basalt - according to Abih or trachyandesite - according to new definitions) softens at 1180°, has the consistency of thick honey at 1260°, and completely liquefies at 1315° (experiments of the author in the Department of Materials Science of the GEEI). The specific heat capacity of Syracuse basalt for various temperatures is shown in the following table:

The heat of crystallization of basalt during the transition from an amorphous state to a crystalline state 130 Cal. During crystallization, the volume decreases by 12% compared with the volume of basalt at a temperature of 1150°. The specific thermal conductivity of basalt in gram-calories is about 0.004. Thermal expansion coefficient of basalt: 0.0000063 (at 20-100°), 0.000009 (at 100-200°) and 0.000012 (at 200-300°).

In chemical terms, basalts are resistant rocks: atmospheric agents, in Gary's experiments, weathered from 1.5 to 0.8 mg / cm 2 of basalt in 18 months, while gray limestone lost 22.7 mg / cm 2 under the same conditions. The process of weathering of basalt and diabase is presented by a comparative diagram (Fig. 2).

The number on the upper horizontal line shows the number of grams of weathered rock that must be taken so that it contains the component corresponding to the designation of the horizontal in question, as much as this part is contained in 100 g of fresh rock. That. all points to the right of the vertical 100 mean depletion of the corresponding part, and those to the left - enrichment. Consequently, during weathering, basalt is enriched in silica and alumina and becomes poorer in alkalis, alkaline earths and iron in all forms, while diabase is enriched in oxide iron and sodium. This circumstance speaks, apparently, against diabase as an insulating material.

3. Bases for processing basalt. The properties of natural basalt make it an excellent building material, more durable than granite. Basalt has been used for a long time. However, the extreme difficulty of processing basalt and dividing it into relatively narrow prisms forced us to come up with a special way of giving it geometric shapes.

It was natural to think about the fusion of this rock, since it itself is of fiery origin. But it is not enough to melt basalt: upon rapid cooling, castings from it give a vitreous mass similar to natural hyalobasalts, fragile and technically inapplicable (Figs. 3 and 4).

The main task of basalt production is the restoration of fine-grainedness in remelted basalt, the so-called regeneration (Fig. 5).

The idea of ​​the possibility of remelting and restoring rocks to their original form arose in the 18th century. Already in 1801, the Scot James Goll achieved the remelting of basalt and, in particular, established that basalt and lavas, being melted and quickly cooled, give glass, while when they are slowly cooled, a stony mass is obtained, with traces of a crystalline structure; this is the basic position of the fiery processing of lavas. Particularly remarkable are the experiments of the Scot Gregory Watt, who expanded the scale of smelting. The melting of a block of basalt more than 3 tons lasted 6 hours, and cooling under the cover of slowly burning coal took 8 days. Watt described the products of this slow cooling: black glass on the surface; as they deepen into the frozen mass, grayish balls appear, grouped into bundles; then the structure becomes radiant; even deeper, the substance has a stony and then granular character, and, finally, the mass is penetrated by crystalline plates. That. the possibility of melting and regenerating igneous rocks was found out. But due to the lack of a sufficiently large need for remelted basalt for industry, the described experiments were forgotten. In 1806 Dobré and then in 1878 F. Fouquet and Michel Levy returned to the smelting and regeneration process. They managed to reproduce almost all rocks of fiery origin and found out that this does not require either extreme temperatures or mysterious agents, but the whole point is to establish the proper regime of melting and annealing. After cooling, the molten silicate turns into glass, the melting point of which is lower than the melting point of the original mineral. To restore the latter, it is necessary to anneal the vitreous mass at a temperature exceeding the melting point of the vitreous body, but lying below the melting point of the crystalline mineral. The temperature range of these melting points is the area in which the regeneration of silicate or aluminosilicate is possible; this interval m. b. pretty insignificant. When it is not a matter of one mineral, but of a combination of 5-6 minerals that make up a crystalline rock, then the annealing regime would have to be set with a number of steps, and each mineral would have its own stoppage of the cooling progress. However, in practice, these steps are so close to each other that we can limit ourselves to two stops. In relation to basalt, the first annealing, with a red-white glow, gives the crystallization of ferrous oxide and peridot, and the second, with cherry-red, crystallization of other minerals of the rock.

The first experiments in the industrial smelting of basalt were undertaken in 1909 by Ribb, and various applications fused basalt were found by engineer L. Dren. In 1913, for the industrial implementation of smelting processes, the Compagnie generate du Basalte was formed in Paris, and in Germany - Der Schmelzbasalt A.-G., in Linz on the Rhine; then both societies united under the common name "Schmelzbasalt A.-G.", or "Le Basalte Fondu". Currently in France there are two plants that produce Ch. arr. electrical and building products, and in Germany one serving the chemical industry.

4. Production of melted basalt. Breaking. The occurrence of basalt is different, and therefore its breaking is not always uniform. Slab-like basalt of mantles or rocks is quarried by blasting. Prisms of columnar basalt can be separated by means of wedges and levers. Development is carried out in tiers, removing successive layers in rows of natural bundles.

Splitting up . Broken basalt is stored outdoors. For smelting, it is crushed in Black or Getz crushers. Then the pieces are sorted by size, and the fines go to the concrete masses.

Remelting. Crushed basalt enters the smelting furnaces, which use various methods of heating. The most suitable ovens are electric, gas (gas generating or with lighting gas) and ovens with oil burners. The electrosmelting plant consists of a fixed electrode furnace and a mobile receiver on wheels, which serves to transport the molten basalt to the casting workshop; this receiver also represents a small electrode furnace. Both types of ovens are powered by two-phase current. The bottom of the furnace is made of refractory material and has a nozzle on the side for discharging the molten mass, while from the receiver it descends into molds or molds for casting by simply tilting the receiver. In other furnaces, the throat is made inclined, so that the loading of the hearth and the descent of the molten mass are carried out in a continuous process. The productivity of the described furnaces is from 3 to 50 tons per day. The Paris plant - of a large-scale handicraft type - has 4 furnaces with a capacity of 80 kg each, operating continuously and heated by city gas; melting is carried out at 1350°. Another French plant, in Puy, runs on electricity. Continuous production capacity - 8 tons per day.

Casting. The molten basalt is poured into molds or molds directly from the furnaces or taken to the casting shops. For casting, either sand trusses or steel molds are used. The first ones are much cheaper, but not applicable in all cases, because the products come out of them dull and rough. Steel molds give products a shiny surface, but are relatively expensive. With careful casting, the casting is clean; otherwise, streaks and irregularities are visible, which in many cases do not prevent, however, the use of the product.

Heat treatment. Almost immediately after casting, the products, still cherry-red, are removed from the molds and transferred to annealing hearth furnaces, similar to ordinary hardening ones. Depending on their purpose and size, the products are aged in the oven from several hours to several days. Initial temperature annealing at about 700°. The oven is covered and slowly cooled; languishing in the furnace lasts, depending on the size of the products and their required qualities, from several hours to 10-14 days. There are up to 35 such ovens at the Paris plant.

Finishing . After cooling, the products are ready for use. To give them a proper look, they are cleaned with steel brushes. If greater accuracy of planar faces is required, then finishing is carried out on circles having a basalt base.

production cost. The production of fused basalt does not require highly skilled labor or expensive equipment. The main costs of production in our conditions are for the delivery of material, if it is brought from the Caucasus, and for energy. When working with gas, 1 kg of finished basalt products requires about 900 Cal, i.e., about 1/4 - 1/3 m 3 of gas; when working with electrical energy Approximately 1 kWh is consumed per 1 kg of products. That. the cost of basalt products, for example, insulators, is much lower than porcelain. In France, the selling price of basalt insulators is 10-15% less than porcelain, and for larger ones - 25-30%. The larger the products, the greater the price discrepancy between basalt and porcelain. However, there are reasons to consider the above discrepancies in selling prices to be significantly underestimated due to the increase in the profit of basalt production as a new business.

Production of smelted basalt in the USSR. With enormous technical and economic advantages behind it, and in some cases, as in the electrification of railways, being almost indispensable, the basalt industry attracted the attention of technical and industrial circles. Experiments with the smelting of basalt and other rocks, undertaken on behalf of the Glavelectro VSNKh in the Department of Materials Science of the GEEI and then at the State Electrotechnical Institute, experiments on the smelting of diabase in the Mining and Metallurgical Laboratory and the interest of the Supreme Economic Council of Georgia and Armenia in this industry can be considered harbingers of the rapid development of basalt business. From an economic point of view, b. a very favorable natural combination of favorable factors was noted: the possibility of extracting basalt very often territorially coincides with the availability of sources of hydroelectric energy for its processing, i.e. with a regional power plant, which requires basalt insulators, and with centers of electrochemical production that need fire and acid-resistant basalt equipment. The indicated coincidence, in connection with the profitability of small basalt plants and the comparative high cost of transport, gives reason to foresee in the future a network of small basalt plants throughout the country.

5. Properties of processed basalt. Melted and regenerated basalt generally has the properties of natural, but in an improved form (see Fig. 3 and 5).

Mechanical properties: a) compressive strength - about 3000 kg / cm 2; b) wear resistance, tested with a Derry mill, powdered with sand, was found to be 0.9 mm average after 1000 revolutions; c) having a high viscosity, basalt does not break easily, and basalt insulators and other products can practically be considered unbreakable. Compared to porcelain, basalt is 2-4 times less brittle; various meanings this value depends on the annealing mode; the presence of impurities brittleness m. highly elevated; d) tensile strength was tested on basalt supports for the third bus of electrical railways. and for comparison, the same sandstone supports were tested; rupture of basalt products was observed at 3700-4700 kg, and the rupture of the same sandstone products - at 1200 kg.

Thermal properties: a) remelted basalt resists temperature changes, even abrupt ones; a plate of basalt 8 mm thick, immersed alternately in boiling water and cold, did not show any signs of cracking; insulators exposed to the sun and then exposed to a thunderstorm, as well as insulators tested according to the rules of the French Union of Electric Syndicates (sudden transfer from water at 65 ° to water at 14 °), showed no change in electrical properties; the upper limit of the thermal interval can be further increased; b) at the moment of solidification, basalt allows for stamping or other introduction of iron parts of any volume into it and adheres firmly to them without requiring cementing; c) basalt endures significant heating without revealing breaks, cracks, "fatigue" or "aging"; d) due to its low thermal conductivity, basalt can serve as a thermal insulator.

Hygroscopicity. Being quite compact and doused with autogenous glaze, basalt is quite waterproof and non-hygroscopic.

Electrical properties: a) basalt has a significant electrical strength: for bridge basalt, it turned out to be about 32 kV / cm with a plate thickness of 18 mm, and for special electrical basalt, both heat-treated and vitrified, it turned out to be from 57 to 62 kV / cm with the same thickness; b) when a breakdown occurs and a powerful arc is formed, the basalt insulator is still not damaged by this, because after the arc stops, the place of the breakdown swims, and the insulator heals without a trace; c) basalt insulators, when processed, are covered by themselves with glass-like basalt glaze 1.5-2 mm thick, gradually turning inward to granular basalt; this glaze is an excellent barrier to surface electrical leakage and protects insulators and other products from hygroscopicity and from the action of atmospheric agents; having a composition identical to the composition of the insulator itself, the glaze adheres to it as a homogeneous body and therefore is not in danger of cracking or peeling off. In addition, when this glaze is forcibly damaged, a substance of the same composition is exposed, so that the indicated damage is not fatal for the insulator.

Chemical properties. In chemical terms, basalt products, according to French information, are very stable; in table. 1 provides data on the effect of various reagents on processed basalt.

Data from further tests are given in table. 2.

Appearance . Remelted, but not annealed, basalt resembles glass: it has a brilliant fracture, brown-black color and is fragile. After annealing, remelted basalt gets black or dark color, matte fine-grained fracture and toughness of natural rock. external view products depends on the material of the mold and the mold (see paragraph 4).

So, in terms of mechanical strength, thermal and chemical resistance, high and unique electrical properties, cheapness and relatively easy workability, processed basalt should be recognized as one of the most remarkable materials in electrical engineering.

6. Application of recycled basalt. The basalt industry is still too young to foresee all the uses of the new material at present. So far, the following have been outlined: a) in networks of strong currents of high and low voltage - linear insulators in the open air (Fig. 6),

support insulators, insulators of the third bus of electrical railways. etc. and subways (Fig. 7), output insulators at high voltage;

b) in low current networks and in radio communications - telegraph and telephone insulators, pull insulators and other insulating parts for antennas; c) in the electrochemical industry - insulating stands for batteries, dishes, bathtubs, etc.; d) in the general chemical industry - acid-resistant equipment, including all kinds of dishes, bathtubs, taps, propellers, etc., equipment for temperatures up to 1000 °; e) in construction - insulating bridges (Fig. 8), bridges, stairs, wall and floor cladding, especially when there are acidic vapors, etc.

Line insulators. In view of the exceptional interest of basalt in electrical engineering, we present test data at the Paris Central Electrical Laboratory of ten insulators with iron pins embedded in them, five of which were previously subjected to a thermal test (see paragraph 5). During a dry test, the first sparks sliding over the insulator appeared at 32.5-38 kV, the arc formed at 35-43 kV, the skirt was broken at 40 kV, and the necks at 37.5-39.5 kV. A wet test under artificial rain produced an arc at 18-20 kV followed by 30 sec. the insulator broke. An oil test established the breakdown voltage at 35-58 kV. The test of pull insulators with alternating voltage, which was raised before the breakdown and then, immediately after the breakdown, began to be raised again until a new breakdown, and so 4 times, gave the results presented in Table. 3.

Telegraph type insulators. A test of high-current basalt insulators, similar to telegraph ones, was carried out at the Moscow Scientific Testing Telegraph Station, and the surface electrical resistance of basalt insulators was found to be significantly higher than that of the corresponding porcelain insulators; but when tested in the rain, the resistance of basalt recovered somewhat more slowly than that of porcelain. This probably depended on the rough surface of the high current insulators tested, for which telegraphy requirements were not taken into account.

7. Other uses of basalt. In addition to the use of natural basalt as a building material and crushed stone, and the use of thermally processed basalt in various industries industry, basalt and related rocks are also used as an integral part in ceramic and glass production. So, Borjomi andesite has been used for several years in the manufacture of glass for bottles under the Borjomi mineral water giving it strength and dark color. The English porcelain factory of Wedgwood has long been producing earthenware with a black, unglazed in mass and easily polished shard, the so-called. "Basalt" (Basalt) or "Egyptian" (Egyptian), - the mass for it contains basalt.

Basalt

During crystallization, as basaltic magma rises to the surface of the Earth, at a depth, strongly differentiated in composition, layered intrusions are sometimes formed, in particular gabbro-norites (such as Norilsk, Sudbury in Canada and some others). In such massifs there are deposits of copper-nickel ores and platinoids.

The main igneous rocks in the CIS are very common. They occupy, taking into account the Siberian traps, 44.5% of the territory of the CIS and are of great interest as raw materials. More than 200 deposits of basalt rocks are known, of which more than 50 deposits are being exploited. Currently, basalts are used not only in construction (crushed stone, piece stone, building cladding, etc.), but also for the production of stone casting, petrositalls, basalt fibers, and raw materials for producing Portland cement clinker.

Origin

Basalts are formed during the solidification of a silicate magmatic melt of the main (basalt) composition that has poured out onto the surface of the Earth, meaning by this the bottom of the ocean. Forms of occurrence - flows and covers, separated by deposits of pyroclastic (tuff) or sedimentary material. The power of individual flows of basaltic lavas, which have a low viscosity in the molten state, is usually small. The origin of basaltic magma, according to one of the hypotheses, consists in the partial melting of typical mantle rocks, harzburgites, wehrlites, etc. The composition of the melt is determined by the chemical and mineral composition of the protolith (original rock), the physicochemical conditions of melting, the degree of melting, and the mechanism of melt escape.

According to the geodynamic nature, there are the following types basalts:

  • mid-ocean ridge basalts
  • basalts of active continental margins
  • intraplate basalts, which can be subdivided into continental and oceanic basalts.

The eruption of mid-ocean ridge basalts is the most important process in terms of mass in the upper part of the Earth.

Changes

Basalts are very easily altered by hydrothermal processes. At the same time, plagioclase is replaced by sericite, olivine by serpentine, the groundmass is chloritized, and as a result, the rock acquires a greenish or bluish color. The basalts that pour out at the bottom of the seas change especially intensively. They actively interact with water, while many components are removed and deposited from them. This process is of great importance for the geochemical balance of some elements. So most of the manganese enters the ocean in this way. Interaction with water radically changes the composition of marine basalts. This influence can be estimated and used to reconstruct the conditions of ancient oceans from basalts.


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Synonyms:

See what "Basalt" is in other dictionaries:

    - (Latin basaltes, from Heb. barsel iron). Mining rock, found in the form of pillars. Dictionary of foreign words included in the Russian language. Chudinov A.N., 1910. BASALT lat. basaltes. Mining stone spilled rock, found in the form of ... ... Dictionary of foreign words of the Russian language- dark dense newest igneous rock. Previously, it was combined into one group, along with many other breeds similar to them in appearance, under the common name of the trap; Subsequently, this group was subdivided into dolerites, anamesites and basalts ... Encyclopedia of Brockhaus and Efron

    basalt- a, m. basalte m., German. Basalt, lat. basaltes. Rock of volcanic origin. Sl. 18. Volcanic rock of fine-grained or dense structure, usually black or dark gray color. ALS 2. First noted. in Sl. comm… … Historical Dictionary of Gallicisms of the Russian Language

    basalt- basalt, basaltic rocks Basalt is a cainotype basic mountain rock. The texture is massive and porous. Zabarvlennya B. dark to black. Efusive analogue of Gabro. H.h. from basic plagioclase, monoclinic pyroxene, olivine, ... ... Girnichiy encyclopedic dictionary

    A dark, effusive mafic rock composed primarily of mafic plagioclase, pyroxenes, and often olivine. Full-crystalline basalts dolerites, with a glassy structure hyalobasalts and tachylites. Basalts occupy huge ... ... Big Encyclopedic Dictionary

    BASALT, a hard, fine-grained mafic igneous rock that can be either INTRUSIVE or EXTRUSIVE. The color of the breed is dark green, brown, dark gray or black. If hardening occurred quickly, it acquired a vitreous ... ... Scientific and technical encyclopedic dictionary

    BASALT, basalt, husband. (lat. basaltes). Rock of volcanic origin. Explanatory Dictionary of Ushakov. D.N. Ushakov. 1935 1940 ... Explanatory Dictionary of Ushakov

    BASALT, a, husband. Volcanic rock dark color. | adj. basalt, oh, oh. Explanatory dictionary of Ozhegov. S.I. Ozhegov, N.Yu. Shvedova. 1949 1992 ... Explanatory dictionary of Ozhegov

Foreword

Basalt is the most common natural stone, a rock of volcanic origin, which can be found in the form of interstratal bodies or lava flows that arose after a volcanic eruption.

Basalt- This is the most common natural stone, a rock of volcanic origin, which can be found in the form of interstratal bodies or lava flows that arose after a volcanic eruption. Rich deposits are located in India, the USA and the Hawaiian Islands. The most famous basalt deposits- These are volcanoes located in Kamchatka and the Kuril Islands, as well as Vesuvius and Etna.

Description: basalt rock with excellent characteristics

The basalt stone It is black, smoky, dark gray or greenish black in color. The basis of its composition is formed by augite and feldspar.

The density of the stone is 2530-2970 kg / m 2;. Water absorption varies from 0.25 to 10.2%. Poisson's ratio is 0.20-0.25. Specific heat capacity 0.85 J/kg K at 0°C. The melting point is in the range of 1100-1250 ° C, in some instances this figure reaches 1450 ° C. The resistance is in the range of 60-400 MPa.

Chemical and mineral composition of basalt

In mineral composition of basalt includes:

The structure of the mineral is porphyrated, glassy or cryptocrystalline aphyric. The rocks of the first variety are distinguished by the presence of a small amount of impurities of black pyroxene prisms, as well as isometric crystals of olivine, which has a yellow-marsh hue. Such inclusions can reach a quarter of the entire mass.

In addition, in composition of basalt hornblende and orthopyroxene may be present. The most common accessory mineral is apatite.

Basalt is mined primarily from lava flows from volcanoes. Pieces mined from the upper part can be bubbly, as during the cooling of the volcanic rock, vapors and gases escape from it. Other minerals can then be deposited in the resulting holes, the most common being prehnite, zeolite, calcium, and copper. This type of basalt is called almond stone.

Practical application of basalt

Building materials made from this stone are widely used in construction, as they are characterized by:

This mineral is used as a building stone, for the production of mineral wool, a filler for concrete and stone casting. Road and facing stones are also made from it, crushed stone and acid-resistant powder are obtained. Facing plates on this moment simultaneously with a decorative purpose, they perform the function of insulators. Thanks to its resistance to weathering, basalt is well suited for finishing the exterior of buildings, as well as for casting street sculptures.

Production of basalt and products based on it

More often basalt production is the mining industry. In special quarries and mines, stone is mined, on the basis of which various products are subsequently produced.

In the form of basalt fiber, this mineral is used for insulation of buildings and roofs, in three-layer sandwich panels, insulation of low-temperature equipment units during nitrogen extraction and creation of oxygen columns, for heat and sound insulation of pipelines, stoves, fireplaces and other braziers, power units and in general buildings and structures for any purpose. Basalt in molten form is used to create stairs, shaped tiles and other building materials. Apparatuses of arbitrary shapes are cast from it, including battery stands, as well as insulators for networks with voltages of various sizes. Powder from such material is used for the production of pressed reinforced products.

Common types of basalt

Types of basalt differ from each other by various indicators, first of all, such as color and structure. The most famous brand name is a variety called "Basaltina". This is a material of Italian origin, which is mined near the capital of this country and has been used mainly for architectural purposes since ancient rome. Its strength is comparable to that of granite, and its decorative qualities are comparable to those of limestone. The stone after laying retains the saturation of the color palette for a long time. Therefore, its cost often exceeds the price of other trademarks more than twice.

Another variety - Asian. It is distinguished by a dark gray color and a reasonable price. It is widely used for design and architectural purposes.

Moorish green basalt has a rich dark green hue, with various inclusions present in it, which give the stone an original appearance while maintaining all physical and mechanical characteristics. Only the criteria for hardness and frost resistance are somewhat lower.

Twilight basalt is brought from China. It has a smoky gray or black color. It is recognized as the strongest and wear-resistant and frost-resistant among all varieties. this mineral. It is well protected from adverse weather conditions.

Watch the basalt rock in the video:

Basalt is the most common igneous rock natural mineral, it turns out from volcanic rocks, after an eruption occurs, its temperature can reach several 1000 ° C.

The stone is quickly recognizable, as it can be dark, black, gray-black, smoky. Most often it has the following appearance: a dark heavy mass, where small light feldspar rectangles and bottle-green eyes of olivine are visible. The mineral is very hard, has a high density equal to 2530-2970 kg / m2, high temperature melting, varying within 1100-1250 ° C,

Under natural conditions, the stone can be seen in the form of flows emanating from an avalanche that appears during the eruption through the existing volcanic cracks. There are several types of this stone: some contain olivine, others do not - they are called tholeiite containing particles of quartz in their composition. Stones with the presence of olivine can be found on the Pacific islands.

Mineral deposits have been discovered in India and America. Many stones are found in the Italian volcanoes Vesuvius and Etna. Today the stone is mined in Kamchatka, in Ireland, Scotland and Iceland. In Ukraine, you can also find their traces.

Basalt - properties and its wide application

The composition of the stone contains: volcanic glasses, microlites, titanomagnetite, magnetites and also clinopyroxene. The mineral has a porous, glassy and latent crystalline aphyric structure.

The properties it has basalt, characterize it as the most reliable and protective element for facing works. The stone has the following properties:

  • fire resistance;
  • strength;
  • durability;
  • soundproofing;
  • thermal insulation;
  • ecological purity.

It contains augite, calcium feldspar and its varieties. Sometimes an admixture of olivine is found.

Thanks to the mineral, high-quality additives to gravel, strong fibers are made, from which heat-insulating and sound-proofing materials are made. Mainly used to create high-quality plates.

Widely used stone in the construction field in the form facing materials, with its help sculptures and various statues are made, and it is also used for the exterior decoration of most buildings. The stone has an unusual property, able to withstand both high and low temperatures, and therefore it is widely used outdoors.

Cladding made from this stone, creates a beautiful appearance of any building. It will remain the same for many years as it was the day it was installed. Its service life spans many decades. It is easy to install, no ties or other reinforcements are needed for this. The stone itself has excellent characteristics that allow you to enjoy the environmental friendliness and durability of the material used and the masterpieces created with it.

Of the large number of slabs available, the most common are slabs containing basalt. They have high strength and lend themselves well to cutting and sawing. They build the most complex and serious structures. These plates are environmentally friendly and do not exert a large load on the foundation.

Plates of this mineral are effectively engaged in the regulation and absorption high level noise in residential buildings and other public places.

Mineral owns a wide range useful properties, capable of not only improving the appearance, but preventing adverse consequences after the construction has been completed and further operation has begun. Noise and sound insulation properties make it possible to provide good conditions to live in residential buildings.

The rock of this mineral has a high fire resistance, can withstand temperatures above 1500 degrees Celsius and is used in the form of fire protection. Minerals can withstand the action of alkalis, acids, paints, have high resistance to abrasion. Serves as an indispensable natural filler for creating concrete blocks.

The main criterion is still the environmental friendliness of this mineral. In molten form, the mineral is used to create steps, stairs, tiles and other building materials. Stone powders are used for the manufacture of reinforced and pressed products.

The black color of the mineral interacts remarkably with silver. They make unusual jewelry, which are a great addition to evening dresses. Light shades of stone are used to make luxurious bracelets, beads, belts, necklaces, as well as various sets.

Basalt - the main origin and process of change

Basalt It is obtained as a result of the melting of rocks, such as: lherzolites, harzburgites, wehrlites. The main composition is determined by the chemical and mineral compounds that contain the protolith and retain the degree of its melting.

Available the following types minerals:

  • oceanic ridges;
  • continental;
  • intraplate.

This type of stone is easily changed as a result of hydrothermal processes. Especially visible are the changes in the stones that pour out at the bottom of the seas and oceans. They vigorously combine with water, while many useful components stand out and settle from them.

In the process of metamorphism, stones can turn into green schists, it all depends on the conditions. And if pressure is applied to them, they can generally acquire a bluish color.