Evaluate how plate tectonic theory helps our understanding of the distribution of seismic and volcanic events (40 marks)

Outline the theories
Supporting evidence

Notes: * Alfred Wegner – suggested that continents were once all joined together in an ancient super continent called Pangaea. Land masses had drifted apart until they got to a certain position. Used 4 different pieces of evidence to help support his theory: 1. Continental Fit – If you placed certain continents together they look like they should/could have been joined together at some point. For example western seaboard of Africa and Eastern sea board of South America. 2. Geological Evidence – Rocks of similar type and age sharing the same formation can be found in South East Brazil and South Africa, which were believed to be joined. Also similar glacial deposits found in the Antarctica, South America and India. 3. Climatological Evidence – Similar coal deposits have been found in places such as Antarctica, North America and UK, all of similar age and all formed in tropical conditions. Neither of these places is still tropical therefore the coal must have drifted apart. 4. Biological Evidence – Fossil formations can be found on either side of the Atlantic. An example of this is the Mesosaurus, this reptile could not fly, however its fossils were found only in South America and South Africa. Therefore they must have been joined; otherwise the fossils would not be in the same place. * Paleomagnestism - The first piece of evidence to support Wegener’s Theory came from the discovery of a ridge of mountains running along the middle of the Atlantic Ocean known as the Mid Atlantic Ridge. 2 British Geologists, Vine and Matthews, discovered magnetic stripes or banding running parallel to the ridge in the 1960s. These stripes corresponded to times when the Earth’s magnetic field