Earth's crust is the upper hard shell of the Earth

The upper hard shell of the Earth is called the bark and enters the lithosphere, which in Greek means literally "rocky" or "hard ball". It also includes part of the upper mantle. All this is directly above the asthenosphere ("impotent sphere") - over a more viscous or plastic layer, as if underlining the lithosphere.

The internal structure of the Earth

Our planet has the form of an ellipsoid, or, more accurately, a geoid, which is a three-dimensional geometric body of a closed form. This is the most important geodesic concept literally translated as "similar to the Earth". This is how our planet looks. Internally it is arranged as follows - the Earth consists of layers separated by borders, which have their own specific names (the clearest of them is the border of Mohorovicic, or Moho, divides the bark and the mantle). The core, which is the center of our planet, the shell (or mantle) and bark - the upper hard shell of the Earth - are the main layers, two of which - the core and mantle, in turn, are divided into 2 sublayers - inner and outer, or lower and upper. Thus, a nucleus whose sphere radius is 3.5 thousand kilometers consists of a solid inner core (radius 1.3) and a liquid outer core. A mantle, or silicate shell, is divided into the lower and upper parts, which together account for 67% of the total mass of our planet.

The Thinnest Layer of the Planet

The upper solid surface of the Earth is a rather thin upper shell (40-80 km on land, 10-15 underwater). It accounts for only 1% of the total mass of the Earth. The Earth's crust consists of two types: the land is continental, the seabed is oceanic. There are also transitional zones, located mainly along the shores of the oceans - island-arc. Territorially the thickest part of the earth's crust falls on the mountains, in particular the Himalayas (75 km), the center of the ocean is its thinnest part (5-7 km). The thickness of the same lithosphere on land and on the ocean floor is 25-200 and 5-100 km, respectively. It should be noted that the lithosphere does not include the entire upper layer of the mantle, but only a small part of it up to several tens of kilometers, while the layer itself reaches between 500 and 900 km.

Physical and chemical compositions of the Earth

The hard shell of the Earth consists of three kinds of rocks - sedimentary (clastic,
Chemical, biogenic), igneous, or igneous (they account for 95% of the entire lithosphere: on land, granites predominate, at the bottom - basalts), and metamorphic (formed in the earth). Under the oceanic stratum of water, the crust consists of two layers. 99.5% of the chemical composition, which has the upper hard shell of the Earth, is hydrogen and oxygen, aluminum and silicon, iron and magnesium, calcium and sodium - only eight elements of Mendeleyev's table. All information about the internal structure of the Earth is a theoretical scientific solutions. For direct study, only the upper hard shell of the Earth is available, because up to the next layer a modern person can not physically reach. Therefore, all questions concerning the structure of our planet are controversial. However, even on the surface, not all is proved and investigated. The very origin of the earth's crust remains controversial. Therefore, all areas of study of the lithosphere are so relevant. It contains available minerals, and in its uppermost part there are soils that are so significant in human life.

Features of the lithosphere

So, the boundaries of the lithosphere can be determined on the interface, which is named after the Serbian geophysicist Mohorovicic, and which is determined from the differences in the velocities of seismic waves. And in these boundaries there are severe, threatening processes of ecological catastrophe - shifts, including tectonic, landslides and mudflows, soil erosion. The soils themselves appeared simultaneously with life on Earth and are the product of the environment - water, air, living organisms and plants. Depending on various conditions (geological, geographical and climatic), this most important natural resource has a thickness of 15 cm to 3 m. The value of some types of soils is very high. For example, Ukrainian chernozem Germans were exported to Germany during the occupation by rolls. Speaking of the earth's crust, we can not say about the lithospheric plates, which are large solid areas, sliding over the more liquid layers of the mantle and moving relative to each other. Their rapprochement and "arrivals" threaten with tectonic shifts, which can be the cause of catastrophes on Earth.