Plate Tectonics and Landscape Essay

1667 Words Mar 21st, 2013 7 Pages
Chapter One
The theory of plate tectonics explains how forces within the planet create landforms. This theory views Earth’s crust as divided into more than a dozen, rigid, slow-moving plates. Some plates are as large as a quarter of the planet, but others are only a few hundred miles across. The plates slowly move across the upper mantle, usually less than an inch per year.
Scientists use the theory of plate tectonics to explain the long history of Earth’s surface. They believe that about a few million years ago, all the continents that we have now today were part of one super continental called Pangaea. Pangaea then broke into two smaller supercontinents called Gandwana and Laurasia. These two then broke into the modern continents we
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The current continental and oceanic plates include: the Eurasian plate, Australian-Indian plate, Philippine plate, Pacific plate, Juan de Fuca plate, Nazca plate, Cocos plate, North American plate, Caribbean plate, South American plate, African plate, Arabian plate, the Antarctic plate, and the Scotia plate. These plates then consist of smaller sub-plates.
There are three different types of plate movements: Divergence, Convergence, and Lateral Slipping.
At the boundaries of the plates, various deformations occur as the plates interact; they separate from one another (seafloor spreading), collide (forming mountain ranges), slip past one another (subduction zones, in which plates undergo destruction and remelting), and slip laterally.
Divergent Plate Movement: Seafloor Spreading
Seafloor spreading is the movement of two oceanic plates away from each other (at a divergent plate boundary), which results in the formation of new oceanic crust (from magma that comes from within the Earth's mantle) along a a mid-ocean ridge. Where the oceanic plates are moving away from each other is called a zone of divergence. Ocean floor spreading was first suggested by Harry Hess and Robert Dietz in the 1960's.
Convergent Plate Movement:
When two plates collide (at a convergent plate boundary), some crust is destroyed in the impact and the plates become smaller. The results differ, depending upon what types of plates are involved.

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