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Walking would not be possible if there was no substrate to support our steps. In the same way that vegetation could not grow without a support to sustain it and animals could not move in search of water and food. In other words, the development of life as we know it today would not be possible without the existence of the earth's crust. Do you know what the earth's crust is? Do you know its characteristics? In Green Ecologist we explain what is the earth's crust: definition for children.
What is the earth's crust
First of all, we must know the structure of our planet. This is formed by four concentric layers:
- Inner core.
- External nucleus.
- Mantle.
- Cortex.
These layers are different from each other due to their composition, characteristics and properties. In this way, the inner core corresponds to the center of the earth and on it, the rest of the layers are arranged, until reaching the Earth crust, what is the outermost layer.
Definition of earth's crust
Therefore, Earth's crust, it's a kind of rcoating that covers the entire surface of the planet, providing a solid foundation on which we ourselves walk and on which they stand, deserts, forests, fields and oceans.
It is mainly made up of rocks of different natures (igneous, metamorphic and sedimentary) and its thickness varies from 5 km at sea level, to 70 km deep in relief areas and mountains.
Besides the crust not a uniform layer, but is divided into parts called plates, which are in a permanent floating stateIn other words, they “float” on the innermost layers of the earth, moving very slowly and almost imperceptibly to humans. However, on some occasions, more abrupt movements occur, which give rise to earthquakes or volcanic eruptions, due to the heat and energy given off in the center of the earth, which causes the plates to move or collide with each other.
Thus, the earth's crust is not something unique, but there are two types of earth's crust:
- The oceanic crust, which covers the part of the planet on which the oceans are deposited, giving rise to the seabed.
- The continental crust that covers the rest of the earth's surface.
Below we explain the characteristics of each of them.
Oceanic crust: definition and characteristics
The oceanic crust occupies approximately the 60% of the Earth's surface and it is composed, for the most part, by rocks of volcanic origin and dark color, such as basalts and gabbros, ranging in thickness between 5 and 10 km.
Contrary to what was formerly believed, the oceanic crust, like the continental crust, may have landforms and landformsTherefore, there are plains, mountains, cracks and submarine volcanoes. In fact, the oceanic crust does not begin on the coast, but several kilometers from it, marked by a steep slope or slope.
In addition, ocean plates they are much younger than continental ones due to the renovation process they are undergoing. This process consists in that, due to the movement of the plates, these can be separated by causing the molten material of the earth's interior to rise and deposit on the oldest layers, or, instead of separating, the plates are superimposed on each other. causing the subsidence of older materials.
Continental crust: definition and characteristics
The continental crust occupies 40% of the earth's surface and it is composed of rocks of different origins, although the majority is made up of metamorphic rocks such as granite and covered by sedimentary rocks such as limestone, sandstone or clay. Its thickness varies between 30 km in the plains and 70 km in the highest mountains.
In it are a variety of reliefs and geographical features, originated by the plate movement. There are areas that, on the contrary, have not suffered any kind of fragmentation or deformation in a long time, called cratons. The cratons, are usually found in the interior of the continents, constituting the oldest and most stable part of the earth's crust and are divided into:
- Shields: when the craton emerges on the surface.
- Platform: when the craton is buried under sediment.
The continental crust is usually much older than the oceanic crust, because it is not subjected to any recycling or renewal process, some of the sections being practically as old as the origin of the Earth.
If you want to read more articles similar to What is the Earth's Crust: Definition for Kids, we recommend that you enter our category of Curiosities of the Earth and the universe.
