2. Introduction
• The lithosphere (or otherwise the earth) is the most
important part of the natural environment, characterized
by area, relief, soil cover, vegetation, subsoil, as well as
space to accommodate all sectors of the national
economy (1-5). The state of the lithosphere changes
over time under the influence of natural forces and
human activities. Natural forces (heat, moisture, wind,
radiation, etc.) and the geological phenomena they
cause (volcanic eruptions, earthquakes, floods, etc.)
significantly change the nature of the lithosphere in
certain regions.
3.
4. Composition of the lithosphere
The lithosphere consists of the earth's crust and the upper part of the
mantle, with which it is firmly attached.
The thickness of the lithosphere in different places on the Earth is not the
same. So under the oceans it is thinner, and on land it has a very
impressive thickness, up to 250 km. Changes in thickness are achieved
mainly by the mantle, not the earth's crust.
Under the lithosphere is a plastic layer of the mantle - molten matter. As
a result of this, the lithosphere can move, and not only horizontally, but
also vertically.
A feature of the Earth's lithosphere is that it is not a single whole. It is
broken into separate parts - lithospheric plates. There are very large,
covering entire oceans or continents, and relatively small plates.
Lithospheric plates move along the plastic layer of the mantle and can
collide with each other or move apart.
5.
6. The structure of the lithosphere
• The term «lithosphere» was introduced by the American
geologist J. Barrell and takes its origin from the Greek word
«lithos» - stone. The lithosphere includes the earth's crust
and the solid part of the mantle in contact with the
asthenosphere.
• The earth's crust is the upper layer of the lithosphere, which
includes almost all the elements of the periodic table of
Mendeleev.
• The thickness and structure of the earth's crust under the
oceans and continents differ. The depth of the continental
crust is 40-70 km, the oceanic one is thinner - the indicator
rarely reaches 15 km, so the continental one is, as it were,
above sea level.
• The continental crust is three-layered. The upper layer is
represented by sedimentary rocks, the 2nd - by granite or
gneiss, the 3rd consists of basalt and other metamorphic
rocks. The oceanic crust lacks a middle layer. The age
indicators of most of the rocks of the continental crust indicate
its «advanced» age relative to the oceanic crust.
7. The earth's crust is based on rocks and fossils. Rocks are natural compounds
of many minerals. There are 3 types of rocks:
Magmatic. Formed by crystallization of magma under high temperature and
pressure:
deep (intrusive) - hardening occurs in the thickness of the crust (granite)
erupted (effusive) - solidification occurs due to the eruption of magma to the
surface (basalt)
Sedimentary. Formed by the accumulation of precipitation on the earth's
surface. Physical and chemical changes in previously formed rocks give the
initial material to sedimentary rocks:
clastic - are formed from rocks that have undergone mechanical stress,
movement and deposition;
chemical - are formed from substances with good solubility, mainly salts;
organic - appear by the decomposition of living organisms;
Metamorphic - are the result of changes in other rocks under the influence of
temperature and pressure at depth.
In the bowels of the earth there is an accumulation of minerals and rocks -
minerals. On the surface or in the bowels of the earth, minerals are in 3 physical
states: liquid (oil, mineral water), solid (ores, metals), gaseous (natural gas).
Depending on the constituent components, minerals are distinguished:
combustible (gas, coal), metallic (lead, copper) and non-metallic (limestone,
clay).
The exhaustible limit of some types of minerals requires rational use in the
needs of mankind.
8.
9. Properties of the lithosphere
The lithosphere has a number of fundamental properties that should be taken into account
when studying it and analyzing the geological process, as well as the process of evolution
of the lithosphere. The most important property of the lithosphere is its variability.
• Variability of the lithosphere
Variability is a general property of matter (hence, the lithosphere), its ability to change in
space and time, reflecting the trend in the development of matter (evolution). The variability
of the lithosphere in time and space corresponds to the forms of existence of matter. The
change in the lithosphere in time, fixed as a change in its components, their relationships
(structure) and properties, is the geological process of the Earth's development.
• Heterogeneity of the lithosphere
When discussing variability, it is impossible not to touch upon the question of
heterogeneity, the relationship between heterogeneity and variability. The variability of
some geological object reflects the properties of space and time of this object. It forms the
heterogeneity of the object, which manifests itself in the difference in its properties at
different points. Consequently, heterogeneity is a manifestation of variability, i.e., its
consequence.
• Anisotropy of the lithosphere
The heterogeneity of the lithosphere is manifested in such important properties as
anisotropy and symmetry-dissymmetry. Anisotropy can be formally defined as the
dependence of some function of a geological parameter on rotation transformations. This
property manifests itself at all levels of organization of the lithosphere: in the form of
structural heights, layering, facies variability, layering, as well as differences in texture,
indicators of soil properties and measures of their dispersion in the main directions of
variability and in depth.
