Tectonic Plate Theories
- Created by: RobynAllday
- Created on: 04-03-14 16:17
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- Plate Tectonic Theorys
- Alfred Wegener
- super continent 'Pangaea' split into two continents of Laurasia and Gondwanaland. theses continents where further split into the land masses we know today as continents.
- geological evidence that supports the theory
- south america and african shapes of continents fit together
- glaciation of the late carboniferous period, where deposits form which were found in South America, Antarctica and India. they must have been formed together and then moved appart
- rock sequences in northern Scotland closely agree with those found in eastern Canada - same conditions in one location
- biological evidence
- fossil brachiopods found in Indian Limestones are comparable with similar fossils in Australia
- fossil remains of the Mesosaurus are found in both South America and South Africa - it is unlikely that the same reptile could have developed in both areas or that it could have migrated across the Atlantic
- the fossilised remains of a plant which existed when coal was being formed have been located only in India and Antarctica
- Sea floor spreading
- the Mid-Atlantic Ridge is a constructive plate boundary, where the two plates are moving away from one another
- As Crust is being created here, somewhere else it mustbe being destroyed, evidence of this is ocean trenches where large areas of ocean floor are being pulled downwards
- when the Earth's magnetic field changes the alignment of the iron particles erupting from the ocean floor also changed, to face the new magnetic 'North'.
- Palaeomagnetism
- the ocean crust gets older with distance from the mid-oceanic ridge.
- the Mid-Atlantic Ridge is a constructive plate boundary, where the two plates are moving away from one another
- Alfred Wegener
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