On Earth, there are a huge number of different rocks. Some of them have similar characteristics, so they are combined into large groups. For example, one of them is carbonate rocks. Read about their examples and classification in the article.
Classification by origin
Carbonate rocks formed in different ways. There are four ways to form this type of rock.
- From chemical precipitation. Thus, dolomites and marls, limestones and siderite appeared.
- Organogenic sediments formed rocks such as algal and coral limestones.
- Sandstones and conglomerates formed from the debris .
- Recrystallized rocks are some types of dolomites and marble.
The structure of carbonate rocks
One of the most important parameters by which the rocks necessary for production and processing are selected is their structure. The most important aspect of the structure of carbonate rocks is their granularity. This parameter divides the rocks into several types:
- Coarse-grained.
- Coarse grained.
- Medium grained.
- Fine-grained.
- Fine-grained.
The properties
Due to the fact that there are a large number of carbonate-type rocks, each of them has its own properties, for which it is very much appreciated in production and industry. What physical and chemical properties of carbonate rocks are known to people?
- Good solubility in acids. Limestones dissolve when cold, and magnesite and siderite - only when heated. However, the result is similar.
- High frost resistance and good fire resistance are undoubtedly the most important qualities of many carbonate rocks.
Limestone rocks
Any carbonate rock consists of minerals of calcite, magnesite, siderite, dolomite, as well as various impurities. Due to differences in composition, this large group of rocks is divided into three smaller ones. One of them is limestone.
Their main component is calcite, and depending on impurities they are divided into sand, clay, siliceous and others. They have different textures. The fact is that on the cracks of their layers you can see traces of ripples and raindrops, crystals of salts that are soluble, as well as microscopic cracks. Limestones can vary in color. The dominant color is beige, grayish or yellowish, and the impurities are pink, greenish or brownish.
The most common limestone rocks are:
- Chalk is a very soft rock that is easy to grind. You can break it with your hands or grind it into powder. It is considered a type of cemented limestone. Chalk is an invaluable raw material used in the production of cement building material.
- Lime tuffs are a porous loose rock. It is fairly easy to develop. Shellfish have almost the same meaning.
Dolomite rocks
Dolomites are rocks with a dolomite mineral content of more than 50%. Often they contain impurities of calcite. Because of this, some similarities and differences between two rock groups can be observed: the dolomites and limestone proper.
Dolomites differ from limestone in that they have a more pronounced brilliance. They are less soluble in acids. Even organic residues are much less common in them. The coloring of dolomites is represented by greenish, pinkish, brownish and yellowish hues.
What dolomite rocks are most common? This, first of all, will cast - a denser stone. In addition, there is soft pink grainerite, it is widely used in interior design. Teruelite is also a type of dolomite. This stone is notable for the fact that in nature it is found only in black, while the rest of the rocks of this group are painted in light shades.
Carbonate-clay rocks, or marls
The composition of carbonate rocks of this type includes a lot of clay, namely, almost 20 percent. By itself, a breed with this name has a mixed composition. Aluminosilicates (clay products of feldspar decay), as well as calcium carbonate in any form, are necessarily present in its structure. Carbonate-clay rocks are a transition link between limestone and clay. Mergels can have a different structure, dense or solid, earthy or loose. Most often, they lie in the form of several layers, each of which is characterized by a certain composition.
High-quality carbonate rock of this type is used in the production of crushed stone. Mergel containing gypsum impurities is of no value, so this variety is almost not mined. If we compare this type of rock with others, then most of all it looks like shale and siltstone.
Limestone
Any classification of carbonate rocks contains a group called limestones. The stone, which gave it its name, has been widely used in various fields of industry. Limestone is the most popular breed in its group. It has a number of positive qualities, thanks to which it has become widespread.
There is limestone of different colors. It all depends on how much iron oxides are contained in the rock, because it is these compounds that color limestone in many tones. Most often these are brown, yellow and red shades. Limestone - the stone is quite dense, it lies underground in the form of huge layers. Sometimes whole mountains are formed, the fundamental component of which is this rock. You can see the layers described above near rivers with steep banks. Here they are very clearly visible.
Limestone has a number of properties that distinguish it from other rocks. Distinguishing them is very easy. The easiest way to do it at home is to drop a little vinegar on it, just a few drops. After that, hissing sounds will be heard and gas evolution will begin. Other breeds do not have such a reaction to acetic acid.
Using
Each carbonate rock has found application in any industry. So, limestones along with dolomites and magnesites are used in metallurgy as fluxes. These are substances that are used in the smelting of metals from ore. With their help, the melting temperature of ores is reduced, which helps to more easily separate metals from waste rocks.
Such a carbonate rock, like chalk, is familiar to all teachers and schoolchildren, because with its help they write on the board. In addition, chalked walls. Powder for brushing your teeth is also made from it, but at present this paste substitute is difficult to obtain.
Limestone is used to produce soda, nitrogenous fertilizers, as well as calcium carbide. Carbonate rock of any of the types presented, for example, limestone, is used in the construction of residential, industrial premises, as well as roads. It is widely used as a facing material and aggregate for concrete. It is also used to obtain feed additives with minerals and to saturate the soil with limestone. Building stones are created from it , for example, gravel and rubble. In addition, cement and lime are produced from this rock, which are widely used in many types of industry, for example, metallurgical and chemical.
Collectors
There is such a variety of rocks as collectors. They have the ability that they can hold water, gas, oil, and turn them back for some time during development. Why it happens? The fact is that a number of rocks have a porous structure and this quality is very much appreciated. It is due to porosity that they can contain a large amount of oil and gas.
Carbonate rocks - high quality reservoirs. The best in their group are dolomites, limestones, and also chalk. 42 percent of the oil reservoirs used and 23 percent of the gas reservoirs are carbonate. These rocks are second only to terrigenous rocks.