Aconcagua

This research has shown that the oceanic crust is under a process of constant destruction and renewal, a process called Seafloor Spreading.

A number of researchers suggested that the earth crust was not just a uniform layer wrapping the whole planet, but, rather, one divided into several different parts, which they called Lithospheric Plates.

A lithospheric plate can include either oceanic crust alone or both continental and oceanic crusts(hybrid plate.)

These plates usually move on an elastic, viscous surface, known as asthenosphere. The speed at which they “float” is different for each plate, and it may even have varied in time. The average speed, however, is estimated between 5 and 10 cm. per year.

Continental Drift, Seafloor Spreading and Plate Tectonic were, therefore, essential theories that led to conclusions concerning the formation of mountain ranges, which redefined earlier and rather rigid conceptions on such orogeny.

It has been proved that movements of the lithospheric plates are responsible for constant changes on the earth’s surface. Such changes take a long (geological) time to become evident. Thus, if the average speed for plate collision and subduction (and eventual generation and destruction) is 5 cm. per year, they would slide 50 km in a million years and 5,000 km in a hundred million years.

There are three different ways in which plates may move relative to each other: a) they slide (grind) past each other, b) they slide apart from each other, and c) they slide toward each other. These movements are usually associated with geological events, such as earthquakes and volcanic activity.