Plate Tectonic Theory

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Plate Tectonic Theory What is Plate Tectonics? Plate tectonics is the main force that shapes our planet’s surface over a long period of time the study of how the Earth's crust is shaped by geological forces. It relies on the understanding that the crust is divided into large pieces, or plates, that sit on the molten interior of the planet. Currents within the interior cause the plates to move, which causes many different geological events, including earthquakes and the forming of mountains and volcanoes. Understanding how plates move and interact is the main purpose of plate tectonics. This picture shows how the rigid outer layer of the Earth, called the crust also known as the lithosphere, is made of plates which fit together like a jigsaw puzzle. These plates are made of rock, but the rock is, in general, lightweight compared with the denser, fluid layer underneath. This allows the plates to "float" on top of the denser material. The crust is made up of two types, the oceanic crust and the continental crust. The oceanic is thinner as its thickness is around 5 – 10 km whereas the continental crust is around 35 to even 70km in mountain areas. The oceanic crust has a higher density than the continental as it is made up of basalt whereas the continental crust is made up of granite which is less dense compared to basalt rock. Due to this difference in densities in magma between the oceanic crust and the continental crust, the continents stay in their places, and both crusts are able to float on the magma. The continental crust floats much more freely on the magma. Movements deep within the Earth, which carry heat from the hot interior to the cooler surface, cause the plates to move very slowly on the surface, about 1 to 10 cm per year. Tectonic plates move because mantle rocks near the radioactive core are heated and the warmer rocks rise while the cooler
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