What is the geosphere?

We explain what the geosphere is and how its structure is. In addition, how this sets of layers is composed and its importance.

1. What is the geosphere?

In the natural sciences , the set of layers that constitute the solid part of the Earth is called a geosphere or geosphere . Together with the hydrosphere (aquatic part), the atmosphere (gaseous part) and the biosphere (set of living beings ), they form the parts into which our planet can be analytically divided.

Like other terrestrial (solid surface) planets, the Earth is formed of rocky materials of different nature and that have different dynamics from each other, many of which date from the first geological periods or were formed during convulsive stages of volcanic activity. Many of the oldest known rocks on the planet date back more than 4400 million years ago.

The study of the geosphere  by geologists and other specialists, is carried out by experimental review of the soils , especially in places where land accidents reveal strata that would normally remain hidden.

In the same way, many observations are theoretical or derived from the calculation: the mass and volume of the earth are not directly measurable, but through other calculable variables, such as gravity , or the reverberation of seismic waves.

2. Structure and composition of the geosphere

The structure of the geosphere is studied from two different perspectives: from the chemical point of view and from the geological point of view.

Taking into account the point of view of its chemical composition, the geosphere comprises three layers: crust, mantle and core.

• Bark  (0 to 35 km deep) . It is the layer of surface rock on which we live, whose relatively thin thickness contemplates anaverage density of 3.0 g / cm3. This includes sea beds and deep depressions. It is made up mostly of mafic rocks (iron and magnesium silicates), felic rocks (sodium, potassium and aluminum silicates).
• Mantle (from 35 to 2890 km deep) . It is the thickest layer of all, composed of siliceous rocks, with a higher iron content than the crust. As we enter the mantle, temperatures and pressures become colossal, achieving a semi-solid state in the rock that composes it, capable of allowing the movement of tectonic plates and being responsible for tremors and earthquakes . Due to the pressure , the upper part of the mantle is less viscous and more mobile than the lower one, varying between 1021 and 1024 Pa.s of magnitude.
• Core (from 2890 to 6371 km deep) . The innermost portion of the planet, where the densest materials are found (Earth is the densest planet in the Solar System). The core is divided into two strata: outer core (2890 to 5150 km deep) and inner core (5150 to 6371 km deep), and is mostly made of iron (80%) and nickel , while elements such as lead and uranium are scarce.

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 and corresponding to the crust and the shallow portion of the mantle. It is fragmented in a series of tectonic or lithospheric plates, at whose edges seismic and volcanic phenomena and orogenesis take place.
• Asthenosphere  (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 the continental drift take place there; but as it gets closer to the core it loses its properties and becomes rigid as the lower mantle.
• Core (from  2890 to 6371 km deep ) . Located at the end of the lower mantle, the nucleus or endosphere is the geological land portion that comprises the largest amount of mass on the planet (60% of the total). Its radius is greater than that of the planet Mars (about 3500 km) and has enormous pressure and temperatures above 6700 ° C. Composed primarily of iron and nickel, it is divided into an outer core of a liquid nature and an inner core of a solid nature. 

3. Importance of the geosphere

The geosphere  is the oldest portion of our planet and where all its secrets are enclosed . Geology scholars try to discover the various processes involved in their formation, which also shed light on the formation of the rest of the solar system’s stars and, therefore, the origin of the universe. The same goes for seismology, a science that tries to understand the nature of geological and tectonic movements to prevent eventual earthquakes and prevent them from being so destructive to humanity.

On the other hand, the study of the geosphere goes hand in hand with the understanding of the materials that we can find on our planet, which has important repercussions in the various industries, engineering and international trade, among other vital areas.