We explain what the terrestrial mantle is and its characteristics. In addition, its function, composition and the definition of the earth's core and crust.
What is the Earth's mantle?
The Earth's mantle is a dense and hot layer of rock that is located inside the planet Earth , between the core and the Earth's crust. It is 3,000 km thick and minerals such as silicates predominate.
It is a structure that does not have a uniform composition , but it is formed mainly by materials that contain silica, oxygen , magnesium , iron , aluminum and other metals .
The temperatures of this area of the Earth vary depending on the proximity or distance of the nucleus. Thus, the area closest to the nucleus can reach a temperature of around 3,500 ° C , while the areas furthest from the nucleus can reach temperatures around 600 ° C.
The terrestrial mantle has two defined layers: the upper mantle and the lower mantle . The upper mantle has a higher viscosity than the lower one, its interior moves very slowly and is responsible for the movement of tectonic plates .
Role of the Earth's mantle
The terrestrial mantle constitutes more than 80% of the volume of the planet Earth and its main function is to be a thermal insulator and refractory of the earth's surface.
The movements of the upper mantle are constant and are produced by convective currents that move the tectonic plates of the Earth. The movement of tectonic plates is vital for the geological development of the planet and the survival of the living beings that inhabit it, since it generates new surfaces.
Magma expelled from the mantle, in processes such as volcanism, forms a new crust where the tectonic plates separate. These are processes that intervene in the carbon cycle , which is essential to regulate the earth's temperature.
Ground control features
Some of the main characteristics of the terrestrial mantle are:
- It is the most extensive layer that makes up the Earth and occupies more than 80% of the planet.
- It is the layer that is between the earth's surface or crust and the nucleus.
- It is made up of the lower mantle and the upper mantle.
- It has temperatures that exceed 600 ° C.
- It extends from 8 km in oceanic areas , 30 km in continental areas and 70 km in mountainous areas .
- It is made up mainly of elements that contain silicon, oxygen, magnesium and iron.
- It is made up of elements in a solid or viscous state .
- It is responsible for the movement of tectonic plates, due to the convection currents that occur within them.
- Its study is based on the materials that emerge to the earth's surface as a result of phenomena such as volcanic activity and orogeny and with the study of seismic waves.
Composition and structure of the terrestrial mantle
The earth's mantle differs from the core and the earth's crust by its composition. Although the composition of the mantle is not uniform, it is mainly formed by silicates , that is, materials composed of oxygen and silicon that, in addition, can contain iron, calcium and aluminum.
There are two well differentiated layers of the earth's mantle: the lower mantle and the upper mantle. Between both layers there is a particular acceleration of seismic waves and their main characteristics are:
- Upper mantle . It begins at the Mohorovicic discontinuity, which is the transition zone between the crust and the Earth's mantle, and is divided into two layers: the lithosphere and the asthenosphere. The upper mantle is a mostly solid structure made up of peridotite and chemical components such as silicon, oxygen, magnesium, and iron. In the asthenosphere the compounds can flow which allows the movement of the tectonic plates. Temperatures in the upper mantle range from 200 to 900 ° C and it is a structure that is more than 600 km thick.
- Inner mantle . It begins in the transition zone after the upper mantle and extends to the Gutenberg discontinuity. It has a thickness that ranges from 700 km to 2,900 km and has a higher temperature and pressure than the upper mantle and the transition zone. It is a solid layer formed by elements composed of silicon and magnesium, such as the mineral perovskite. Most of the known evidence for this layer comes from investigations of the magma that emerges from the Earth after volcanic activity.
The core and the earth's crust
In addition to the Earth's mantle, planet Earth is made up of two other structures:
- The earth's crust . It is a thin layer that can range from 5 to 50 km thick, it is the outermost layer of the Earth and living beings inhabit it. It is made up mainly of oxygen, silica, and aluminum. The boundary between the crust and the mantle is named after its discoverer, the geophysicist, Andrija Mohorovicic and its function is to separate the materials of higher density (iron silicate, magnesium) from those of lower density (calcium, potassium or sodium).
- The core . It is a sphere with a radius of 3,400 km that constitutes the innermost part of the Earth and is composed mainly of iron. The transition zone between the core and the Earth's mantle is known as the Gutenberg discontinuity. It is under this discontinuity that the Earth's magnetic field originates. The nucleus is divided into:
- External core . It is located between the mantle and the inner core and is in a liquid state .
- Inner core . It is the innermost layer of the Earth and is in a solid state.
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