Why are there Ocean Basins, Continents, and Mountains?
Over millions of years, ocean basins open and close, continents move and change shape, and mountains are pushed up and eroded away. Such dynamic processes continually reshape the surface of the Earth. The movement of rigid plates on the Earth’s surface, known as plate tectonics, is the cause of these changes. Volcanic eruptions and earthquakes are dramatic hints of the great movements that take place over the vastness of geological time.
Topic: Earth Science
Subtopic: Earth Formation/Evolution
Keywords: Earth (Planet)--Surface, Plate tectonics, Landforms, Geological time, Geology, Structural
The globe before you is a model of the solid Earth.
Most explosive eruptions occur in volcanoes above subduction zones, where one tectonic plate dives beneath the other.
People associate volcanoes with spectacular explosive eruptions, yet most volcanoes erupt basalt, a fluid lava from the mantle that erupts effusively and forms flows.
No other natural force compares in sheer power with earthquakes.
The mountain ranges that span the globe mark boundaries where the Earth’s plates converge.
Plate tectonics has emerged as one of the grand unifying theories of geology.