In order to begin to discover the meaning of the term asthenosphere, we are going to know its etymological origin. In this case, we can establish that it is a word of Greek origin that is formed as the sum of several components of said language:
-The prefix “a-“, which can be translated as “without”.
-The noun “sthenos”, which is synonymous with “force”.
-The name “sphaira”, which is equivalent to “sphere”.
The term asthenosphere is not part of the dictionary. The concept is used to name the layer of the earth’s mantle located between two hundred and fifty-six hundred kilometers deep, below the area called the lithosphere.
The asthenosphere is made up of semi-cast and solid materials. Above it floats the lithosphere, a rigid layer made up of the outer layer of the mantle and the Earth’s crust. In this way, the movement of the tectonic plates occurs over the area of the asthenosphere.
The state of equilibrium called isostasis (which is achieved from the different densities of the parts that make up the Earth’s surface) and continental drift (the phenomenon caused by the masses of the continents when moving) are possible thanks to the existence of the asthenosphere, where movements are developed through convection.
Another feature of the asthenosphere is that it promotes the renewal and expansion of the ocean floor. This is due to the fact that basalt is found in its composition, an igneous rock that, through an extrusion process, flows through the ocean ridges. When it meets the continent, matter sinks and passes below, returning to the ocean floor and melting within the asthenosphere by subduction.
In addition to all the above, it is worth considering other aspects of interest in the asthenosphere, such as the following:
-It is composed of magnesium and iron silicates, in addition to basalt.
-It is identified because, in the same way, it contains what is the magma that volcanoes come to expel when they erupt.
-It is considered to be the weakest region in the upper layer of the Earth, from a mechanical point of view.
-It is also established that it is the region with the highest viscosity.
-Among the most important characters in the establishment of the asthenosphere and their knowledge are Dutton, Joseph Barrell, Beno Gutenberg or John Tuzo Wilson. Names to which those of Anton Halles, Sengör and Burke should be added …
It is important to mention that, for some scientists, the asthenosphere does not really exist. There are specialists who maintain that continental drift is produced by a joint movement of the crust with the mantle, while isostasis would develop between the outer part of the Earth’s core and the inner part of the mantle.
A subject of debate, the one referring to the existence or not of the asthenosphere, which still continues to generate enormous controversy. Hence, at present, there is no position that is considered accurate in this regard, since there are many studies that are established in one position and in another without being conclusive.