Meaning of Lithosphere
What is Lithosphere:
The most superficial layer of the earth's sphere is called lithosphere. The word lithosphere is of Greek origin lithos which means "stone" and sphaira which expresses "sphere".
Structure of the lithosphere
The lithosphere is a rocky layer that varies in thickness in the great depths of the sea and in mountainous regions. It is formed by a terrestrial and oceanic crust and by the contiguous zone, the outermost, of a solid and residual mantle. It also floats on the asthenosphere, a soft layer that is part of the upper mantle.
The lithosphere is the area where plate tectonics occurs in interaction with the asthenosphere. That is why the lithosphere layer is fragmented by a series of tectonic plates, on whose edges endogenous geological phenomena, such as seismicity, magmatism or orogenesis, are grouped.
Characteristics of the lithosphere
- The lithosphere is related to other layers, such as the hydrosphere, the atmosphere and the biosphere, undergoing various alterations as a result of them.
- The lithosphere is chemically composed of oxygen, sulfur, aluminum, iron, calcium, sodium, potassium, magnesium, and silicon. Likewise, it is formed by minerals and rocks that can be igneous, sedimentary and metamorphic.
- The lithosphere extends up to 100 km deep sunk in the mantle.
- The density of the lithosphere is 3 tons / m3.
- The lithosphere can be classified into continental and oceanic crust.
For more information, see the article atmosphere and biosphere.
Continental and oceanic lithosphere
The lithosphere can be classified into continental crust and oceanic crust. The continental crust is up to 70 km thick of plutonic and metamorphic rocks and is made up of mountains, ranges, hills, plateaus, plains, valleys and depressions.
For its part, the oceanic crust has a thickness between 5 and 10 km of basalt, plutonic rock, sediments and minerals that are denser than the previous crust. The oceanic lithosphere is formed through volcanism in the form of fissures in the mid-ocean ridges.
Thermal and seismic lithosphere
The thermal lithosphere constitutes the part of the mantle where heat convection predominates, so it can be stated that the lithosphere has a defined temperature and a certain fraction of the ambient or ambient temperature. solidus of the mantle.
Regarding the seismic lithosphere, according to seismological studies there is evidence of a reduction in the propagation speed of secondary waves and a high attenuation of primary waves.
Lithosphere and asthenosphere
The depth ranges from 78.86 - 99.78 km.