Lithosphere: definition for children

Our planet Earth is made up of different elements as we have seen in previous lessons. All these parts are necessary for life to occur, in fact, it is what differentiates our planet of the others that make up the solar system because for now it is the only one in which there is lifetime. In this lesson from a TEACHER we bring you the kids definition of lithosphere to get closer to the knowledge of the geology and nature of the Blue Planet.

We begin the children's definition of the lithosphere by answering this question. The lithosphere is the rigid part of the planet, that is to say the crust and the upper part of the mantle.

This word comes from the Greek and means stone sphere. In turn, it is divided into plates, which we know by the name of tectonic plates, on which the continents in which we live are based and where the oceans.

These plates are not fixed at all, moving gradually, being that what causes waves in the oceans.

As such, the lithosphere is one, although researchers have made a kind of subgroups, taking into account the different elements that compose it. In this way we can find:

• Seismic lithosphere: part of the lithosphere where the propagation of seismic waves is carried out at a much higher speed than in the rest.
• Thermal lithosphere: we can center it on the Earth's mantle, a place where heat conduction predominates over the rest of the elements.
• Elastic lithosphere: it is the part of the lithosphere where the tectonic plates are located, therefore, we will find a certain movement.

Within the definition for children of the lithosphere, we must know that of these three subgroups, it will be the elastic lithosphere the one with the greatest thickness. In addition to this, the channels that come out of the core of the earth reach, through which gases and lava are expelled to the outside.

Within the definition for children of the lithosphere, we will now focus on mentioning the various parts of which it is made up:

Earth crust

It is the outermost part of the planet and at the highest part it is up to 70 km thick, while at the bottom of the oceans it is only about 5 km. It is composed of various minerals such as:

• Quartz
• Feldspar
• Mica

In this other lesson from a TEACHER we will discover the parts of the Earth both internal and external.

Tectonic plates

As we have said before, the Earth is divided into plates. They are fragments that move quite rigidly (that is, they have little mobility, rather what they do is rub against each other). Result of these friction between plates, we will find the volcanic eruptions, earthquakes, giant waves and also the creation of the mountain ranges that exist today.

The latter originated when two very hard plates collided, causing one of them to constrict until creating a mountainous system. Therefore, we must know that these they are always on the move, being when they collide in great intensity when the natural phenomena cataloged as natural calamities occur.

At present it seems that only our planet has active tectonic plates, although according to the latest studies seem to be that planets like Venus or Mars at the time could have them active.

Ocean crust

It occupies 55% of the Earth's surface and is divided into three levels:

• Tier I: it is made up of sediments that are deposited on the crust, due to maritime movements and the erosion of the continents.
• Level II: made up of basaltic and volcanic rocks, which come from oceanic eruptions, which, when in contact with water, create this type of rock.
• Tier III: It is the layer attached to the earth's mantle and is made up of gabbros and plutonic rocks.

For the most part, it is found under the sea, at the bottom of the oceans, but there are exceptions such as the ridges mid-oceanic waters found in Iceland and the Republic of Dijibouti where they rise above the level of the sea.

It has a thickness of between 6-12 km depending on the place and it seems that the oldest rocks studied so far are 180 million years old.