core, mantle and crust - is the internal structure of the Earth.And what the lithosphere?So-called external inorganic solid shell of our planet.This includes all the crust and upper mantle.
In simplified form, the lithosphere is the top layer of the Earth, consisting of three layers.In the academic world there is no single definition of this planetary shell.And on its part of the same debate is going on.But reportedly it is still possible to make the basic idea of what the lithosphere.
structure, composition and boundaries
Despite what the lithosphere includes absolutely all the earth's surface and the upper layer of the mantle, in a weight equivalent is expressed in only one percent of the total mass of our planet.Although the shell has a small volume, a detailed study has caused a lot of questions, not only about what the lithosphere, but also the material from which it is formed, in which the state is in different parts.
constitute the main part of the shell solid rock at the frontier with the mantle acquire plastic consistency.The structure of the Earth's crust is isolated stable platform and folding area.
crust has a different thickness and can range from 25 to 200 kilometers.On the ocean floor is thinner - from 5 to 100 kilometers.Earth's lithosphere is limited to other shells: the hydrosphere (water) and atmosphere (air).
stacked three layers of the earth's crust:
- sediment;
- granite;
- basalt.
So if you look at what the lithosphere in a cut, it will resemble a layer cake.Its basis is basalt, and the top is covered with a layer of sediment.Between them, as the filling is granite.
sedimentary layer on the continents formed as a result of destruction and modification of granite and basalt rocks.On the ocean floor like bedding formed by the accumulation of rivers submitted a continental sedimentary rocks.
granite layer is composed of metamorphic and igneous rocks.On the continents, he occupies an intermediate position between the other layers, and on the ocean floor it is completely absent.It is believed that in the "heart" of the planet is basalt, composed of igneous rocks.
crust is not a monolith, it is made up of individual blocks, called lithospheric plates that are in constant motion.They seem to float on the plastic asthenosphere.
Environmental problems lithosphere
During its existence, mankind in the economic activity is constantly used components of the lithosphere.The Earth's crust contains all the mineral resources that are widely used by people, and their extraction from the bowels constantly increasing.
great value is the soil - the preservation of the fertile layer of the lithosphere is now one of the most urgent problems requiring immediate solutions.
Some of the processes occurring within the boundaries of the shell, such as erosion, landslides, mudflows, may be caused by human activities, and pose a threat.They not only affect the formation of ecological situations in certain areas, but also may lead to global environmental disasters.
