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Physical Environment > Paleomagnetism |
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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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The Earths magnetic field reverses roughly every half million years. When iron containing rocks are formed (in sediment or in solidified volcanic larva) they may become magnetised, so creating a record of which way the field was pointing.
The reversal of the earths field is unpredictable and forms a recognisable pattern over time. By comparing these patterns in rocks from different continents we can work out which rocks were formed at the same time. This old magnetism is called paleomagnetism. Study of it was vital in establishing the theory of continental drift. |
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Physical Environment > Paleomagnetism |
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Basic Information |
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