Magmatic (igneous) rocks owe their formation to magma, after it erupted from the bowels of the Earth, cooled and froze. They represent the earth's crust by 90 percent or more. And the entire earth's surface is sedimentary and igneous rocks. They extend almost 15 km deep into the Earth.
The main igneous rocks, formation conditions
As a result of tectonic activity, some parts of red-hot magma break into the upper earth layers.
If during the cooling of erupting structures they do not have time to crystallize, then such rocks represent an uncrystallized whole structure. This is usually pumice or obsidian.
Eruptions (igneous rocks) are usually divided into clastic and massive. The former are formed by the destruction of the latter.
Based on the conditions of formation of igneous rocks, the depth of their occurrence, they are divided into coarse-grained, medium-grained, fine-grained and micro-grained.
Since these rocks arise from magma under various cooling and hardening conditions, it is customary to divide them into effusive (poured out) and intrusive (deep) ones.
Massive rocks
They were formed due to the fact that red-hot magma slowly cooled at a considerable depth under conditions of high pressure. This led to the complete crystallization of the spilled rocks. They are represented by granites, syenites, gabbros and diorites. These igneous deep rocks are of considerable density, they have a pronounced coarse-crystalline structure.
Granite
Granite is the most famous deep erupted rock. It consists, as a rule, of quartz, mica, feldspar. In some cases, mica is replaced by dark, ferruginous, magnesian minerals.
The coloring of granite is directly dependent on its main component - feldspar and dark minerals. It can acquire red, gray and other shades.
Granite grains have a high degree of cohesion. As a result of this, its fractures go along the grains of minerals. High strength, resistance to weathering and frost release granite as a material with exceptional building characteristics. It is widely used for the manufacture of various products. Among them are facing slabs, stairwells, curbs, etc. It is widely used in construction work as a derivative of crushed stone of various fractions. Granite found its application in the construction of hydraulic structures, as well as in monuments and monuments.
Its high physical mechanical characteristics affect its longevity. It can reach more than one and a half thousand years.
Syenite
This igneous rock consists of feldspar (orthoclase) in combination with any other material painted in dark colors. Syenite is similar in structure to granite. However, it is softer in handling. It is better polished, as it has a high viscosity. Syenite is used in the same areas as granite. Between granite and syenite there is also an averaged structure called granisienite.
Diorite
The rock diorite is somewhat denser than granite. Usually painted in shades of green. This material is very laborious to process. It has a significant resistance to abrasion, it is highly polished, practically does not weather. The main areas of application are road construction, facing panels.
Gabbro
It is a crystalline igneous rock, which consists of plagioclase and dark minerals. Sometimes biotite and hornblende are included in the gabbro structure . The colors of this mineral are gray, green to black. Labradorite also belongs to gabbro rocks.
Gabbro has a very high density. It is steady against weathering, it is difficult to process, but polishing keeps for a long time. Basically, this material is used in the construction of hydraulic structures, in the production of crushed stone, in facing slabs.
Labradorite, which is quite a beautiful material, due to its colors is widely used in facing works.
Spilled rocks
The igneous volcanic rocks that came to the surface of the earth, as well as the deep, have the same physical and mechanical properties. However, they have a crystalline and glassy structure. They are formed due to the release of magma to the surface with its subsequent solidification. Such rocks include quartz porphyry, trachite, diabase, basalt.
Quartz porphyry
It is actually an analogue of granite. Its structure is glassy, ββthere are inclusions of large quartz grains in it. Weathered, they fall out of its breed. Usually this material is used as crushed stone or piece stone.
Trachyte
In terms of its chemical and mineralogical composition, this rock is very similar to porphyry. It was formed on the surface of the Earth in much later geological periods. The mineral is distinguished by high porosity and low strength characteristics.
Diabase
In fact, an analogue of gabbro. Very durable material. Its usual color is dark gray. Perfectly polished. Mainly used as starting material for the production of crushed stone. Piece stones, plates, paving stones are made from diabase. There is its use as a facing material. During the reign of diabase (1200-1300 degrees Celsius), various products flow from it. This material (fused diabase) is resistant to acids and alkalis. It has high dielectric properties.
Basalt
By its chemical and mechanical parameters, it is actually a complete analogue of gabbro. The color shades of basalt are dark. It contains a small amount of volcanic glass. Very dense mineral. Given their high strength and hardness, basalt stones are used as a material for paving. He found his application in stone casting.
Debris
Formed as a result of the deposition of debris from igneous rocks. They have a granular structure with the presence of grains of various sizes. They are divided into loose rocks, which include volcanic ash, pumice, and cemented (represented by volcanic tuff).
Pumice
It is formed during cooling of magma, when there is a fast and intense exit of gases from it, which at the same time swell it. This process leads to the appearance of a porous glassy rock. The colors of pumice are varied, mainly these are structures of gray, black or white shades. 70% of the rock is represented by silica and 15% by alumina.
Usually it forms fractions from 5 to 50 mm in diameter. The density of pumice is low, and porosity reaches 80% of the volume. This breed has found application as crushed stone to create lightweight concrete, as a heat-insulating material.
Volcanic ash
It is a powder of gray, black color. It is used as a component structure for cement mortars or light concrete, as mineral additives to cementitious mortars.
Volcanic tuffs
Formed during solidification of liquid lava, when sand and ashes are added to it. Due to the rapid cooling, glassy structures are obtained. The color is mostly pink with purple hues.
Use volcanic tuff as sand and gravel for lightweight concrete. Wall blocks, active additives to cement are made from it.
Given that the tuff is endowed with good frost resistance, and also has decorative qualities, it is used as a facing material for building facades.
Mining methods
Erupt rocks in construction are widely used. Extraction of natural stone occurs in places of significant occurrence (deposits). Depending on different conditions, production methods are as follows:
- drilling and blasting;
- burocline;
- stone-cutting.
Drilling and blasting method is a sequence of measures, among which - drilling holes in the faces, laying charges in them with subsequent blasting. Thus, rock breaking from the massif is carried out. It is mainly used for solid igneous rocks.
With the wedge method, the stone is processed around the perimeter with pneumatic punchers. Hydraulic or mechanical wedges are introduced into the formed recesses, with the help of which the rock is split along a given plane. It is mainly used in relation to layered rocks and having cracks.
In the case of the stone-cutting method, special stone-cutting machines with carbide saw blades are used. Are applied to work with soft breeds.