Plate Tectonics.

Essay by maximiusJunior High, 9th gradeA+, November 2003

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Plate Tectonics

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Plate tectonics are a somewhat new method of analysis that has radically changed the way geologists think about the Earth. According to the new theory, Plate tectonics, the surface of the Earth is broken into several differently, and large, sized plates. The size and position of these plates change over time due to earthquakes, the plates colliding, etc, but we will explain this later. The hypothesis of continental drift was majorly developed by Alfred Wegener, a German man, the edges of these plates, and where they move against each other, are sites of intense geologic activity, such as earthquakes, volcanoes, and mountains being formed.

Plate tectonics is a combination of two earlier ideas, continental drift and sea-floor spreading. Continental drift is the movement of continents over the Earth's surface and in their change in position relative to each other. Sea-floor spreading is the creation of new oceanic crust at mid-ocean ridges and movement of the crust away from the mid-ocean ridges.

Plate Boundaries are located around the outside of a plate. That is where the plates will collide. There are several different types of boundaries, Divergent Boundaries, Transform Boundaries, Subduction boundaries, and Collisional Boundaries.

A divergent boundary occurs where two plates move apart, allowing magma, or molten rock, to rise from the Earth's interior to fill in the gap. The two plates move away from each other like two conveyor belts moving in opposite directions. Plate movement takes place laterally away from the plate boundary, which is normally marked by a rise or a ridge. The ridge or rise may be offset by a transform fault. Currently, most divergent boundaries occur along the central zone of the world's major oceans. What we call this process is sea floor spreading. The Mid-Atlantic Ridge and...