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 were formed in different ways. There are four ways to form this type of rock.
- From chemical fallout. Thus, dolomites and marls, limestones and siderite appeared.
- From organogenic sediments, rocks such as algal and coral limestones were formed.
- Sandstones and conglomerates formed from debris.
- Recrystallized rocks are some types of dolomite and marble.
Structure of carbonate rocks
One of the most important parameters by which 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 separates breeds into several types:
- Coarse.
- Coarse-grained.
- Medium grained.
- Fine.
- Fine-grained.
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 are the physical and chemical properties of carbonate rocks known to people?
- Good solubility in acids. Limestones dissolve in a cold state, 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 the minerals calcite, magnesite, siderite, dolomite, as well as various impurities. Due to differences in composition, this large group of rocks is subdivided into three smaller ones. One of them is limestone.
Their main component is calcite, and depending on the impurities, they are divided into sandy, clayey, siliceous and others. They have different textures. The fact is that on the cracks of their layers one can see traces of ripples and raindrops, s alt crystals that are soluble, as well as microscopic cracks. Limestones can vary in color. The dominant color is beige, greyish or yellowish, while the impurities are pink, greenish or brownish.
The most commonlimestone rocks are as follows:
- Chalk is a very soft rock that rubs easily. It can be broken by hand or ground into powder. It is considered a type of cemented limestone. Chalk is an invaluable raw material used in the production of the building material cement.
- Lime tuffs are porous loose rock. It is fairly easy to develop. Shells have almost the same meaning.
Dolomite rocks
Dolomitic are rocks with a dolomite mineral content of more than 50%. Often they contain impurities of calcite. Because of this, one can observe some similarities and differences between the two groups of rocks: dolomites proper and limestone.
Dolomites differ from limestone in that they have a more pronounced brilliance. They are less soluble in acids. Even the remains of organic matter are much less common in them. The color of dolomites is represented by greenish, pinkish, brownish and yellowish hues.
What are the most common dolomite rocks? This, first of all, will throw - a denser stone. In addition, there is a pale pink grinerite, it is widely used in interior design. Teruelite is also a variety of dolomite. This stone is remarkable in that it occurs in nature only in black, while the rest of the rocks of this group are painted in light shades.
Carbonate-argillaceous rocks, or marls
The composition of carbonate rocksthis type includes a lot of clay, namely, almost 20 percent. The breed itself with this name has a mixed composition. Its structure necessarily contains aluminosilicates (clay decomposition products of feldspar), as well as calcium carbonate in any form. Carbonate-argillaceous rocks are a transitional link between limestones and clay. Marls can have a different structure, dense or hard, earthy or loose. Most often, they occur 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. Marl, containing gypsum impurities, is of no value, therefore this variety of it is almost never 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 that gave it its name has been widely used in various industries. Limestone is the most popular rock in its group. It has a number of positive qualities, thanks to which it has become widespread.
There are different colors of limestone. 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 is a fairly dense stone, it lies underground in the form of huge layers. Sometimeswhole mountains are formed, the fundamental component of which is this rock. You can see the layers described above near rivers with steep banks. You can see them very well here.
Limestone has a number of properties that distinguish it from other rocks. It is very easy to distinguish between them. The easiest way that you can do at home is to put some vinegar on it, just a few drops. After that, hissing sounds will be heard and gas will be released. Other breeds do not have this reaction to acetic acid.
Use
Each carbonate rock has found application in some industry. Thus, 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 point of ores is reduced, which helps to more easily separate metals from waste rocks.
Such a carbonate rock as chalk is familiar to all teachers and schoolchildren, because it is used to write on the blackboard. In addition, the walls are whitewashed with chalk. It is also used to make dentifrice powder, but this pasta substitute is currently hard to come by.
Limestone is used to produce soda, nitrogen fertilizers, and calcium carbide. Carbonate rock of any of the presented types, for example, limestone, is used in the construction of residential, industrial premises, as well as roads. He got widedistribution as a facing material and concrete aggregate. It is also used to obtain mineral feed additives and to saturate the soil with limestone. Building stones are made from it, for example, crushed stone and rubble. In addition, cement and lime are produced from this rock, which are widely used in many types of industry, such as metallurgical and chemical industries.
Collectors
There is such a variety of rocks as collectors. They have an ability that allows them to hold water, gas, oil, and then give them back during development. Why is this happening? The fact is that a number of rocks have a porous structure and this quality is very much appreciated. It is due to their porosity that they can contain large amounts of oil and gas.
Carbonate rocks are high quality reservoirs. The best in their group are dolomites, limestones, and also chalk. 42 percent of the applied oil reservoirs and 23 percent of the gas reservoirs are carbonate. These rocks are second only to terrigenous ones.
