Igneous rocks

1.

Igneous rocks
Prepared by: Ilnar Umyrzhanov
Idarovich TR-3-1

2.

Igneous rocks (magmatites) are the end products of magmatic
activity resulting from the solidification of natural melt (magma,
lava). The transition of the melt to the solid state is accompanied by
crystallization of the substance. Igneous rocks play an important role
in the structure of the earth's crust, forming geological bodies of
various shapes and sizes, compositions and structures.

3.

Magmatites are one of the most important types of rocks
along with sedimentary, metamorphic, and hydrothermalmetasomatic formations. They occur in a wide range of
geological conditions: shields, platforms, orogens, oceanic
crust, etc. Igneous and metamorphic rocks by volume make up
90-95% of the upper (16 km) of the earth's crust. Igneous
rocks form about 15% of the modern surface of the Earth.

4.

The characteristics of igneous rocks depend on the depth of their solidification.
On this basis, three groups are distinguished: volcanic - volcanics and
subvolcanics solidified on the surface of the earth, solidified near it; hypabyssal
- formed at shallow depths; plutonic (plutonites) - deep bedding rocks.

5.

In the composition of igneous rocks, rock-forming
and accessory minerals are distinguished. Rockforming minerals are represented by various
aluminosilicates and silicates. Among them, there
are light-colored (syn. Leucocratic) and darkcolored (syn. Melanocratic, colored) varieties.
Light-colored ones do not contain (or contain
only impurity) magnesium and iron, while darkcolored ones are characterized by the inclusion of
these elements in the composition of crystal
lattices. Accordingly, salic (from Si, Al) and mafic
(from Mg, Fe) minerals are distinguished.

6.

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