Plate Tectonics Summary For Children
The Earth is a living and constantly changing entity. Some changes take place over hundreds of years that, if we think of the 4.543 billion years of its estimated age, represent only a few seconds for it. Mountains, plains, volcanic eruptions… All these movements can be explained through Plate Tectonics for Children.
What is Plate Tectonics? explanation for children
Plate Tectonics is a theory that explains how the Earth is changing and how its surface, the lithosphere, is reorganized through an ongoing process of creation and destruction.
Dan Mackenzie was one of the main people responsible for finding the answer to the formation of mountains and underwater abysses. Since then, more than 50 years have passed and we have had to wait for modern technology to show us how the Earth is formed.
The Earth is composed of 4 layers, liquid and solid, and surrounded by a dome of gases: the geosphere, the biosphere, the hydrosphere and the atmosphere. However, in this article, we will focus on the sublayers of the geosphere to understand plate tectonics for children:
- Earth Nucleus: also called the endosphere. It consists of a solid interior and a liquid outer layer.
- Asthenosphere: sublayer formed by solid rocks subjected to high temperatures and pressures, which gives it a high ductile character. The lithosphere plates are floating on it.
- Earth’s Mantle: represents most of the planet. It is located between the earth’s crust and the outer layer of the core. It is divided into: upper mantle, transition zone and lower mantle.
- Lithosphere: is the solid sublayer of the earth preceded by the earth’s mantle and anterior to the crust, although it is possible to say that the upper part, the mantle and the earth’s crust are part of the lithosphere.
- Oceanic and continental crusts: it is the outermost layer of the geosphere and the thinnest comparatively.
Where are the tectonic plates? Plate tectonics for children
The lithosphere consists of at least 57 rigid plates of different sizes: 15 major or major and 42 minor. The shocks that occurred as a result of their movement are responsible for the remodeling of the Earth’s crust based on interactions at the edges of the plates.
The most important are: African, Antarctic, Indo-Australian, Eurasian, North American, Pacific and South American.
How does the lithosphere move?
Tectonic plates move due to convection currents and gravity. As we’ve already mentioned, the asthenosphere is a plastic layer on which the lithosphere rests. When heated, part of the rocks dissolve, which favors the movement of the plates and the rise of these materials, which are now less dense and which, when cooled, sink again. This is what we call “convection currents”.
Plates are, therefore, rigid pieces of earth, which flow independently over the liquid layer of the asthenosphere and within whose limits earthquakes and volcanic eruptions occur.
These limits can be of three types, according to the relative motion of the lithospheric plates: divergent or constructive (of separation), convergent or destructive (of approximation), and sliding or transforming (parallel).
Remodeling of the crust on the edges of tectonic plates
John Tuzo, Canadian geologist and geophysicist, was another great author of the current theory of plate tectonics. Thanks to his pioneering research on transform faults, he was able to justify the perpendicular and parallel displacements at the edges, thus clarifying what happened at the limits of the plates.
Convergent limits
They occur when the movement of tectonic plates causes them to collide head-on, causing an elevation. For example, this is how the Himalayas formed 55 million years ago, due to a clash between the Asian and Indian plates.
They can also occur when an oceanic plate enters beneath a continental one. In these cases, the crust is destroyed in a process called ‘subduction’.
Then, the continental plate is elevated, forming mountain ranges along the sea, like the Andes, while the oceanic one melts when it reaches the asthenosphere, rising in the form of lava through the volcanoes.
Divergent Limits in Plate Tectonics
If the separating plates are oceanic, a hole appears in the earth, as if it were a crack. This place is used by magmatic rocks to outcrop to the surface of the crust, thus creating a new oceanic crust. In this way, the oceanic ridges (underwater elevations) that connect the oceans are formed.
If, on the contrary, it is two terrestrial plates that are separating, they will create a deep depression, like the great Rift Valley that, over time, within millions of years, will cause the eastern part of the African continent. separate.
transforming limits
In these areas, the plates do not collide but have a parallel and opposite movement. This causes seismic movements, some imperceptible and others impressive, such as earthquakes, such as the one in Chile in 1960, of 9.6 on the Richter scale, or tsunamis, like the 9.3 degree in Indonesia in 2004. One of the transforming faults most important on the planet is San Andrés.
We hope that this simple summary of the theory of plate tectonics for children will be useful to help them understand the phenomena that cause transformations on the Earth’s surface.
