• what are tectonic plates?
• Types of tectonic plates
• Main tectonic plates
• Plate tectonics map
• Plate tectonic movements
• Tectonic plate collision

We explain what tectonic plates are, their types and which are the main ones. Also, what happens when they move and collide.

The Earth's lithosphere is divided into segments called plate tectonics.

what are tectonic plates?

The tectonic plates or lithospheric plates are the different fragments into which the lithosphere terrestrial, that is, the most superficial layer of the planet, where the Cortex and the upper part of the earth's mantle. On its edges, seismic, volcanic and orogenic activity is concentrated.

The latter is due to the fact that the tectonic plates are in constant motion on the asthenosphere, a more or less viscous area of ​​the upper mantle, according to what is established in the theory of plate tectonics.

Not much is currently known about the nature of plate tectonics, other than that they are rigid and that their displacements produce geological phenomena whose impact we can measure and know, such as earthquakes and earthquakes, the volcanoes. They can even cause the genesis of mountain ranges and sedimentary basins. This is a phenomenon active only in the planet Earth. However, there is evidence that other planets they once had similar tectonic phenomena.

The theory of plate tectonics, which explains these phenomena, was formulated between 1960 and 1970, and is the result of more than two centuries of geophysical and geochemical observations, as well as the often indecipherable findings of the fossil and geological record. . It was formulated based on the theory of continental drift developed in 1912 by the German Alfred Wegener (1880-1930).

Types of tectonic plates

There are two types of tectonic plates in the world: oceanic and continental.

• Ocean plates. Those covered entirely by the oceanic crust, that is, the floor of the oceans, so that they are submerged to their full extent. They are thin, composed mainly of iron and magnesium.
• Continental plates. Those partially covered by the continental crust, that is, by the continents themselves, they are the most predominant type of tectonic plate and generally have a continental part and another submerged in the Water of the seas.

Main tectonic plates

In total, our planet has 56 tectonic plates, of which 14 would be the most important. These are:

• The African plate. It covers the entire African continent and extends towards the ocean around it, except in its northern part.
• The Antarctic Plate. It covers Antarctica in its entirety, then spreading out into the surrounding oceans along its nearly 17 million square kilometers.
• The Arabic plate. It is located under the Arabian peninsula and part of the so-called Middle East, it comes from a fracturing of the African plate and holds 43% of the reserves of gas and 48% of Petroleum of the world.
• The plate of Cocos. It underlies the Pacific Ocean in the western coast region of Central America, just off the Caribbean plate, under which it forms the volcanic arches of the Central American region.
• The Nazca plate. Located under the eastern Pacific Ocean, off the coasts of Peru, Ecuador and Colombia, as well as the central and northern regions of Chile, it is subducted to the South American plate, thus forming the Andes mountain range.
• The Juan de Fuca plaque. A small plate located on the western side of the North American plate, on the Pacific coasts of California, Oregon, Washington, and British Columbia. This, together with the Cocos plate and the Nazca plate, comes from the disintegration of the old Farallon plate around 28 million years ago.
• The Caribbean plate. As its name indicates, it is located in the Caribbean region, north of South America and to the east of Central America, extending for 3.2 million square kilometers. It covers a Central American continental portion (Guatemala, Belize, Honduras, Nicaragua, El Salvador, Costa Rica, Panama and the Mexican state of Chiapas), as well as all the islands of the Caribbean Sea.
• The Pacific Plate. One of the largest on the planet, it covers almost the entire ocean of the same name, and has numerous "hot spots" and seismic or volcanic zones, especially towards Hawaii.
• The Eurasian plate. Covering a territory of 67,800,000 square kilometers, this huge plate covers all of Eurasia (Europe Y Asia whole), with the exception of the Indian subcontinent, Arabia and part of Siberia. It also stretches for several kilometers over the eastern part of the North Atlantic Ocean.
• The Philippine plate. Located in the Pacific Ocean, east of the Philippines, it is a subducting plate right at the region from the Mariana Trench. It is quite small compared to its neighbors.
• The Indo-Australian plate. As its name suggests, this plate stretches from India's border with China and Nepal, across the entire Indian subcontinent, the Indian Ocean, and the entirety of Australia and Melanesia, culminating in New Zealand. It is the result of the merger of the ancient Indic and Australian plates about 50 million years ago.
• The North American plate. It is home to North America in its entirety, including Greenland, as well as the archipelagos of Cuba, The Bahamas, half of Iceland, and part of the North Atlantic oceans, the Arctic Glacier and the Siberian territory. It is the largest plate on the planet.
• The Scotia badge. Located at the junction of the Pacific, Atlantic and Antarctic Glacier oceans, in southern South America. It is a small and relatively recent plate, born in the Cenozoic. It has intense seismic and volcanic activity.
• The South American plate. Just like the continent with which it shares its name, this plate is located below the entirety of South America, also extending in a southeastern direction towards the South Atlantic Ocean.

Plate tectonics map

Plate tectonic movements

Tectonic plates move over the Asthenosphere, the fluid portion of the Earth's mantle. They move at different speeds, generally slow, but constant, in such a way that they are imperceptible, except when they collide with others and then we perceive the seismic waves of the impact.

Sayings movements They are due to factors that are not yet clear, but that could have to do with the Earth's rotation, with the displacement of warm magma upwards and cold towards the bottom, or even differences in the gravitational forces and of density of the planetary crust.

However, the movements occur as part of the dynamics of the earth's mantle, where there are convection and distribution currents of the heat, which allows the matter it remains in a semi-solid state and that the densest and heaviest elements descend, making room for the lighter ones.

Tectonic plate collision

When plates collide, earthquakes, volcanoes, or even mountains can occur.

Eventually, tectonic plates collide with each other at their limits, where so-called "tectonic faults" or other similar geological phenomena usually occur. For example:

• Tremors and earthquakes. They have to do with the waves generated by the friction of the plates and their transmission through different layers of materials.
• The mountainous formations. They are due to folds and distortions of the tectonic plates, when they exert resistance against each other in a frontal way, preventing their displacement and forcing a deformation.
• The volcanoes. They are due to the subduction of one tectonic plate below another, that is, to the fact that one is introduced below the other, penetrating the mantle and therefore coming into contact with the boiling magma, whose excess liquid rock is will then expel in the form of eruptions.