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Physical Environment > Continental Drift |
This site tells the story of the history of the universe. Click Earlier and Later to follow the story. Note: Many facts have been simplified to make them easier to understand. |
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At some stage in history a process called continental drift began. We do not know when because the rocks have been squashed and changed so much since then, but it is important because it is still happening today. Some people think that it is one cause of ice ages.
It is the heat generated by radioactive decay inside the Earth which drives this process. Today the theory of plate tectonics, which includes continental drift, forms a framework for the study of geology and the earth. For the evidence that continental drift is happening, click here. |
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 | Hot rock rises up from the mantle and spreads out on the surface to form the ocean floor. As the ocean floor spreads it pushes the continents around. They move one or two centimeters each year. | |
 | As the continents move around they sometimes hit each other, creating mountains. This is how the Alps and the Himalayas were created. Mountains like this are on the inside of continents. | |
 | Sometimes continents do not hit head on, but rub past each other. Since they do not have smooth edges, the rubbing is jerky and uneven. Pressure builds up and is then suddenly released. This creates earthquakes. The San Andreas fault in California is an example of this. | |
 | In some places the floor sinks back down into the mantle, usually at the edge of a continent. As it sinks it melts and hot rock rises up, creating volcanoes along the coast. The Andes are being created in this way. Sometimes the volcanoes lie in an arc just off the coast of a continent. The islands of Japan are being formed like this. | |
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Physical Environment > Continental Drift |
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Basic Information |
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