Asthenosphere is the layer of the interior of the Earth that expands approximately between 50 and 100 km in depth, probably formed by viscous materials that can deform, the asthenosphere is located between the lithosphere and the mesosphere. The term asthenosphere is not part of the dictionary of the Royal Spanish Academy (RAE). The concept is used to name the mantle of the Earth's mantle located below the area called the lithosphere.
The asthenosphere is composed of semisolid and solid materials. Above it floats the lithosphere, a rigid layer composed of the outer sector of the mantle and the earth's crust. In this way, the movement of tectonic plates occurs in the area of the asthenosphere.
The asthenosphere is malleable and can be pushed and deformed, like modeling clay, in response to Earth's heat. These rocks really flow; moving in response to stress imposed by movements of the Earth's deep interior. The fluid asthenosphere carries with it the Earth's lithosphere, including the continents.
Another characteristic of the asthenosphere is that it promotes the renewal and expansion of the ocean floor. This is due to the fact that in its composition is basalt, an igneous rock that, through an extrusion process, flows through the oceanic ridges. When it meets the continent, matter sinks and passes under it, returning to the bottom of the ocean and merging within the asthenosphere by subduction.
In geology as a scientific discipline, isostatic theory holds that mountains are not the result of an excess charge on the surface, but rather that their origin is due to movements that occur in the inner layers, both in the lithosphere and in the asthenosphere..
It is important to mention that, for some scientists, the asthenosphere does not really exist. There are specialists who argue that continental drift is produced by a solidarity movement of the crust with the mantle, while isostasy would develop between the outer part of the Earth's core and the inner part of the mantle.
A subject of debate is the one referred to the existence or not of the asthenosphere, which still generates great controversy. Therefore, at present, there is no position that is considered accurate in this regard, because there are many studies that settle on one position and another without being conclusive.
