How do plate tectonics work?

PLATE TECTONICS

Earth’s crust is the brittle shell of a deep layer of hot rock called the mantle. This is moving very slowly, driven by heat generated deep within the planet. The movement has made the crust crack into separate plates, which are being pulled apart in some places and pushed together in others. As they move, the plates make oceans larger or smaller, and carry continents around the globe.

PLATE BOUNDARIES

At some plate boundaries the plates are pulling apart, while at others they are pushing together. There are also places where one plate is sliding against another. All these movements cause earthquakes, and many boundaries are dotted with volcanoes.

Convergent boundaries

These are found where one plate grinds beneath another. Ocean floors always slide under continents, pushing up mountain ranges.

Divergent boundaries These occur where plates are pulling apart, usually on ocean floors. This allows hot mantle rock to erupt in the rift zone and solidify as new ocean floor.

KIT OF PARTS

There are 15 large tectonic plates, and almost 40 smaller ones. They form the ocean floors, and some of the largest carry continents. Continental plates are made of thicker, but lighter, rock than the ocean floors. The oceanic parts of the plates are always changing size and shape, but the continents, although moving, do not change so much.

FRACTURED GLOBE

The plates fit together to form the globe. Some plates are moving apart at divergent boundaries, but the world never gets bigger because the fringes of other plates are being destroyed at convergent boundaries. The relative movement of the Pacific, Cocos and Caribbean plates shows how the plate boundaries are formed.

Picture Credit : Google

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