LITHOSPHERE: CHARACTERISTICS, COMPOSITION, STRUCTURE, FUNCTIONS - GEOGRAPHY - 2025

The lithosphere is the most superficial crust on Earth. It is a rigid layer that covers the entire planet and where plants and many animal species are found. Therefore, it is the place where life exists in all its forms, simple and complex.

Its name comes from the Greek lithos, which means rock or stone; and sphaíra or sphere. The lithosphere is part of the geosphere, one of the four terrestrial subsystems along with the hydrosphere, the atmosphere and the biosphere.

The lithosphere is the most superficial rigid layer on Earth. Source: wikipedia.org

It is located on the asthenosphere, which corresponds to the remaining mantle of the Earth's crust. It is made up of a solid and rigid material, and is divided into different tectonic plates that move producing different types of movements.

This terrestrial layer contains all the geological diversity that exists on the planet. All ecosystems only occur in this segment of the Earth, and these are the most important elements for life.

The lithosphere contains components such as gold, aluminum, iron, and many minerals that give man the possibility of creating products and tools, which facilitate work and other areas of his life.

In the 19th century, various geographical phenomena related to relief were observed. This gave rise to multidisciplinary investigations that have tried to give answers to all the variations of the terrestrial layer.

Between 1908 and 1912 the observations made by Alfred Wegener served as the basis to this day to explain the causes of the tectonic activity of the lithosphere, which lead to phenomena such as orogeny, volcanoes, earthquakes and other mountain formations.

characteristics

- It is the most rigid of all the terrestrial layers, since it is composed of sediments and remains of rocks and minerals that disintegrate and give it an inflexible consistency.

- It is made up of many types of rocks, minerals, metals and precious stones. In addition, it has properties that help generate well-being and benefits to the human being.

- In the crust of the Earth there are forests rich in elements such as wood, rubber, resins and firewood, useful products for human life.

- It is also composed of natural substances and living beings, water and gases capable of creating the humus of the earth that, when decomposed, make it suitable for cultivation.

- In some points of the lithosphere the temperature and pressure register very high values, in which rocks can even melt.

- The lithosphere is the coldest layer of the Earth's inner layers, but as it descends it becomes increasingly hotter.

- Convective currents occur in the lithosphere, which give rise to changes in the relief.

- It is isolated in plates that have areas of tectonic, seismic or volcanic action, depending on the separation or cut points.

- It is the propitious element where ecosystems for flora and fauna, sources of food for life, are generated.

Composition

The lithosphere is made up of a crust that can reach from one meter to 100 kilometers deep. In this layer, the elements that make it up are basically stone or basalt rocks of strong thickness and very rigid.

The so-called continental lithosphere is basically composed of felsic minerals, such as granite or igneous rocks that form quartz and feldspar.

This layer of dense rocks is mainly made up of iron, silicon, calcium, potassium, phosphorus, titanium, magnesium and hydrogen. In less quantity there is carbon, zirconium, sulfur, chlorine, barium, fluorine, nickel and strontium.

For its part, the crust of the oceanic lithosphere is of the mafic type; that is, based on a silicate mineral rich in iron, pyroxene, magnesium and olivine. These rocks are also made up of basalt and gabbro.

Towards the upper mantle the silicate of iron and magnesium predominates, and in the lower one there is a mixture of oxides of magnesium, iron and silicon. Rocks are obtained both in solid and semi-molten state, which are generated by the temperature changes that can occur in certain areas.

The core of the lithosphere is the deepest layer and is basically made up of iron and nickel. There is an upper and a lower nucleus; in the latter, temperatures reach temperatures of over 3000 ° C.

Structure

The structure of the lithosphere is made up of two layers: an outer layer, also called the crust, and the upper mantle. In turn, they comprise 12 tectonic plates with rigid characteristics.

The upper mantle is isolated from the crust at a depth of more than 2,500 kilometers, and the core has an outer layer of more than 2,000 kilometers.

From this layer, twelve plates are formed that are shown as sections of the lithosphere. These move separately from each other, inflexibly.

The most prominent feature of the lithosphere is its tectonic activity, which describes the interaction between large slabs of lithosphere called plate tectonics.

The so-called plate tectonic hypothesis explains the elements and the structure of the Earth's surface, establishing that these plates always advance towards the next layer called the atnosphere.

The displacement of the plates generates three types of tectonic limits: the convergent, the divergent and the transformation one. In each of these there are movements that generate geographical changes; These variations not only modify the relief, but also the ecosystems in general.

Convergent limits

It is the space in which the plates make lateral movements to each other, colliding and producing wrinkles in the crust, thanks to which mountain chains are created. Examples of this type of boundary are Mount Everest and the Andes in South America.

The same thing happens in oceanic plates through a process called subduction, in which the plate that is submerged in the mantle dissolves, which produces volcanic eruptions.

Divergent limits

From the separation of two plates new land masses can be produced. In oceanic plates, the rise of magma emerging from the depths to the surface exerts a force that creates a gap between two or more tectonic plates.

Transformation limits

Within the limits of transformation two plates push each other in so-called slip faults.

These limits are not so strong as to form oceans or mountain formations; however, these displacements can generate earthquakes of great magnitude.

Most important tectonic plates

The tectonic plates cover all the continents of the planet, there are around 15 and their names are related to the region where they are located.

Some are oceanic and others continental. The most prominent are the Eurasian plate, the Pacific plate, the South American plate, the North American plate, the African plate and the Arabian plate, among others.

Eurasian plate

It is located in Europe and in most of the Asian territory, including Japan and covering the entire seabed east of the Atlantic ridge.

It is an area of ​​much collision with other plates, which generates great volcanic activity. This area integrates the well-known belt of fire.

Pacific Plate

Make up the entire belt of fire. It is one of the largest oceanic plates and is in contact with eight other plates.

South American plate

This plate has a convergent limit in the western zone, it is very seismically active and has important volcanoes.

North American plate

This area also forms the ring of fire, and on its western side it connects with the Pacific plate.

African plate

It is a mixed type plate that in its northern limit generated the Alps and the Mediterranean, in its collision with the Eurasian plate.

In the west the ocean expands and it is said that in Africa an opening is gradually formed, which in the future will produce a division of this continent.

Arabic plate

It is a small size plate. In its western limit the Red Sea is in the process of opening, which is considered the most recent marine body.

Features

Being one of the most important layers on Earth, the lithosphere is well known to many people. However, little is usually known about specific data related to this layer, as well as about the importance it has for our environment.

The lithosphere is the layer on which the biosphere is supported; therefore, it is the area where the living beings of the planet are found. The most important functions of this layer can be summarized in two great facts:

Environment for life

The exchange process between the biosphere and the lithosphere makes it possible for the organic elements found in the latter to remain buried in the crust and decompose to contribute to the production of other elements such as gas, oil and coal. that are very useful for the industry.

In addition, by combining with the hydrosphere and the atmosphere, it generates a constant source of nutrients. Thanks to this, living beings can perform their biological functions, interacting and maintaining the balance of the ecosystem through food chains.

In this layer the soils are prepared for planting, which will provide food. Likewise, thanks to this layer, high temperatures do not consume the water from the oceans and life has an environment conducive to its development.

In the higher elevation areas of the continental crust, water is led into the oceans, creating sources of fresh water such as rivers and lakes.

Geological phases

The lithosphere has the function of isolating the hot temperatures found at the bottom of the Earth so that wildlife can be given, a source of nutrients for flora and fauna.

The changes in the relief are the product of the movements and displacements that occur inside the tectonic plates of the lithosphere.

Thermal energy moves between the earth's crust and the core, transforming itself into mechanical energy. This causes convective currents to occur along the mantle that give rise to the formation of mountainous reliefs.

These currents cause earthquakes and volcanic eruptions that can be catastrophic in the short term. However, these displacements and surface changes in the lithosphere result in the long-term formation of new habitats, plant growth and the stimulation of adaptation processes.

Most of the natural and mineral resources, as well as metals and precious stones, are deposited in this layer. These are developed due to the elements that compose it and all the biological exchange that takes place within the geosphere, thanks to the ideal characteristics provided by the lithosphere.

Lithosphere types

There are two types of lithosphere: the continental lithosphere, which is located in the outermost part and has an approximate thickness of between 40 and 200 kilometers; and the oceanic lithosphere, located in ocean basins between 50 and 100 km thick.

Continental lithosphere

It is made up of the outer part of the earth's mantle and the continental crust. It is approximately 120 kilometers thick and is essentially made up of granite rock. This layer is made up of the continents and mountain systems.

Oceanic lithosphere

It is made up of the outer mantle of the Earth and the oceanic crust. Its thickness is thinner than that of the continental one: it is approximately 60 kilometers.

It is made up mostly of basalts, and at the bottom mountain ranges up to 7 kilometers thick are formed.

With the passage of time, the oceanic lithosphere becomes increasingly dense due to the cooling of the asthenosphere, becoming a lithospheric mantle. This explains why the oceanic lithosphere is younger than the continental one.

It also explains the fact that, when a continental plate joins the oceanic plate in so-called subduction zones, the oceanic lithosphere usually sinks below the continental lithosphere.

Depending on the thickness of the different layers of the lithosphere, three other types can be distinguished: the thermal, seismic and elastic lithosphere.

Thermal lithosphere

In the thermal lithosphere the part of the mantle that conducts heat predominates.

Seismic lithosphere

The seismic lithosphere is the place where the reduction of the speed of the waves of terrestrial movement takes place.

Elastic lithosphere

The elastic or flexural lithosphere is the space in which the movement of tectonic plates occurs.

References

1. "Lithosphere" in Layers of the earth.org. Retrieved on May 18, 2019 from Capas de la tierra.org: capadelatierra.org
2. "Lithosphere" in Wikipedia the free encyclopedia. Retrieved on May 19, 2019 from Wikipedia the free encyclopedia: es.wikipedia.org
3. Portillo, G. "The lithosphere" in Network Meteorology. Retrieved on May 19, 2019 from Meteorology on the net: meteorologiaenred.com
4. "Lithosphere: What is it ?, Characteristics, composition and more" in My solar system. Retrieved on May 20, 2019 from My solar system: misistemasolar.com
5. Ibañez, J. "The deep life of the lithosphere" in Foundation for knowledge Madrid +. Retrieved on May 20, 2019 from the Madrid + Knowledge Foundation: madrimasd.org