We explain what the geosphere is and what its structure is like. Also, how is this set of layers composed, and what is its importance?
What is the geosphere?
In the natural sciences, the set of layers that constitute the solid part of the Earth is called the geosphere or geosphere. Together with the hydrosphere (aquatic part), the atmosphere (gaseous element), and the biosphere (all living beings), they make up the parts into which our planet can be analytically divided.
Like other terrestrial planets (with solid surfaces), the Earth is made up of rocky materials of different natures that exhibit different dynamics, many of which date back to the earliest geological periods or were formed during explosive stages of volcanic activity. Many of the oldest known rocks on the planet date back more than 4.4 billion years.
The study of the geosphere by geologists and other specialists is carried out through the experimental review of soils, especially in places where accidents in the terrain reveal strata to the surface that would typically remain hidden.
Similarly, many observations are theoretical or derived from calculation: the mass and volume of the Earth are not measurable directly but through other calculable variables, such as gravity or the reverberation of seismic waves.
Structure and composition of the geosphere
The structure of the geosphere is studied from two perspectives: from the chemical and geological points of view.
From the point of view of its chemical composition, the geosphere comprises three layers: crust, mantle, and core.
- Crust (from 0 to 35 km deep). It is the surface rock stratum on which we live, whose relatively thin thickness contemplates an average density of 3.0 g/cm3. This includes seabeds and deep depressions. It mainly comprises mafic rocks (iron and magnesium silicates) and felsic rocks (sodium, potassium, and aluminum silicates).
- Mantle (from 35 to 2,890 km deep). It is the thickest layer, composed of siliceous rocks, with a higher iron content than the crust. As we enter the mantle, temperatures and pressures become colossal, achieving a state of semi-solidity in the rock that composes it, capable of allowing the movement of tectonic plates and being responsible for tremors and earthquakes. . Due to pressure, the upper part of the mantle is less dense and more mobile than the lower part, varying between 1021 and 1024 Pa.s in magnitude.
- Core (from 2,890 to 6,371 km deep). The innermost portion of the planet is where the densest materials are found (Earth is the densest planet in the Solar System). The core is, in turn, divided into two layers: the outer core (from 2,890 to 5,150 km deep) and the inner core (from 5,150 to 6,371 km deep), and is composed mostly of iron (80%) and nickel. , while elements such as lead and uranium are in short supply.
Instead, from a geological point of view, the geosphere is divided into:
- Lithosphere (from 0 to 100 km deep). This is the solid portion of the geosphere, where the solid rocks are, corresponding to the crust and the superficial part of the mantle. It is fragmented into a series of tectonic or lithospheric plates, at whose edges seismic and volcanic phenomena and orogenesis take place.
- Asthenosphere (from 100 to 400 km deep). Composed of ductile materials in a semi-solid to solid state, corresponding to the Earth’s mantle. The slow movements that make up continental drift occur there, but as it gets closer to the core, it loses its properties and becomes rigid, like the lower mantle.
- Core (from 2,890 to 6,371 km deep). Located at the end of the lower mantle, the core or endosphere is the terrestrial geological portion that comprises the planet’s largest mass (60% of the total). Its radius is greater than that of the planet Mars (about 3,500 km), and it has enormous pressure and temperatures above 6,700 °C. Composed mainly of iron and nickel, it is divided into an outer core of liquid nature and an inner core of a solid nature.
Importance of the geosphere
The geosphere is the oldest portion of our planet and where all its secrets are locked up. Geology scholars try to discover the various processes involved in its formation, which also shed light on the construction of the rest of the stars of the Solar System and, therefore, the universe’s origin. The same happens with seismology, a science that tries to understand the nature of geological and tectonic movements to prevent possible earthquakes and prevent them from being so destructive to humanity.
On the other hand, the study of the geosphere studying writing with understanding the materials we can find on our planet, which has significant repercussions in various industries, engineering, and international trade, among other vital areas.