Tectonic Plates

The tectonic plates are rigid blocks of lithosphere which drift over the surface of the Earth. They move in different directions, separating from one plate to collide against another. The planet Earth’s crust is not one indivisible layer of rocks but it is broken up into large pieces, which are called plates. The movement of each one of these plates causes what is known as the continental drift. Their existence is based on the theory of plate tectonics, which dates back to the 1920s, when the German geophysicist, Alfred Wegener, first explained how a large original supercontinent broke up into smaller ones that drifted apart to take today’s present positions. If you take a look at the diagram/map below this article, you will have a clear picture of them.

Cause

The breaking up of the lithosphere into several drifting plates is caused by the immense inner pressure exerted by the mantle’s molten rocks that are squeezed upwards by convection currents. It means that the molten rocks flows in streams between the lower mantle and the upper mantle in a circulatory pattern. This, in turn, caused the formation of the different continents from a primeval continental mass. The molten rocks are ejected up in the form of lava onto the planet’s surface through what is known as subduction zone, which is the place where two tectonic plates meet, with one pushing against the other. This gives birth to mountain ranges and volcanoes.

Number of plates

Although the tectonic plates are separated from one another, they are held together by the upper mantle. When they move, each plate carries land mass and the ocean floor. The planet Earth has more than twelve different plates, with the exact number of them depends on where the geologists establish the plate boundaries. Most of the scientists agree that there are the following tectonic blocks: South American, Nazca, Cocos, Caribbean, North American, Pacific (the largest plate), Juan de Fuca, Australian, Eurosian, African, Somali, Anatolian, Aegean, Indian, Philippine, and Antarctic Plate. The Nazca Plate moves and pushes against the South American Plate, with a long subduction zone being the boundary, as this geological collision caused the folding and elevation of rocks and geological materials that shaped the Andes Mountain Range. African Plate collides against the Eurasian, the Aegean, and the Anatolian Plate.

Below, you can see a map of the Earth that show the different tectonic plates