Plate Tectonic theories

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Alfred Wegener
Proposed the theory of continental drift. He suggested that all the plates were joined together in a super continent called Pangaea which drifted apart. Wegener based his theory on geological evidence and fossil records.But couldn't back it up with a mechanism that explained how the continents moved.But in the 1950s, palaeomagnetism provided evidence that supported continental drift. And in the 1960s the process of sea floor spreading was discovered-it provided the mechanism for continental drift. 

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Evidence for Continental drift
Geology -Areas of South America and Africa have rocks of the same age and composition- if you fit these continents together, the distribution of the rocks matches up.-You can also match up mountain ranges, eg Mountains in Scotland, Norway, Sweden and Finland are similar to the east coast of North America.-These rocks and mountains must have been formed under the smae conditions and the same place in order to match so well- this would only be possible if the continents were once joined.

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Fossil Records By fitting land masses you can match up the distribution of some fossils eg fossils of Lystrosaurus and Mesosaurus Living Species The same living organisms can be found on different continents.Climatology There's evidence that the past climates of some continents were similar, despite being thousands of miles apart now. This suggests that they were located together and in different places Poalaeomagnetism Study of earths magnetic fieldOnce every 200,000 years the Earth's magnetic field reverses polarityProvides evidence for sea floor spreading As magma erupts from the mid-ocean ridges, magnetic minerals in the molten rock align themselves with the direction of the earths magnetic field.

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