Explain the evidence for sea-floor spreading (6)

Sea-floor spreading is the lateral movement of new oceanic crust away from the mid-ocean ridge and this process links to Wegener’s (1912) Theory of Continental Drift since it determines the movement of the tectonic plates. Therefore explaining how Pangea was broken up and how the continents have reached their current formation. This process of sea-floor spreading is evidenced through Paleomagnetism and glacial deposits. Paleomagnetism is the record of changes in the earth’s polarity and it gave rise to this idea of sea-floor spreading since this technology of seafloor mapping highlighted the earth’s bathymetry and the small variations in the Earth’s magnetic field which showed a striped pattern across the ocean floor. It is this symmetrical pattern of geometric reversal on either side of the mid-ocean ridge which supports this concept of sea-floor spreading. This is because, as the lava erupts, it cools and the magnetic orientation of the iron within the lava is ‘locked’ in the rock depending on the earth’s polarity at the time whilst simultaneously the older rock is ‘pushed’ away from the mid-ocean ridge. Therefore, Paleomagnetism showed the changes in magnetic polarity that sea-floor spreading results in. Furthermore, there is evidence of sea-floor spreading through glacial deposits since deposits formed during the Permo-Carboniferous glaciation are found in Australia, Africa, Antarctica, India and South America. Therefore, if the continents were to not have moved it would suggest that an ice sheet extended from the South Pole to the Equator. This being highly unlikely as the UK at this time was also close to the equator and contrastingly has extensive coal and limestone deposits. Whereas, if the continents of the Southern Hemisphere are reassembled near the South Pole then the Permo-Carboniferous ice sheet is a much more realistic size. Showing therefore that this sea-floor spreading has led to continental drift and this dispersion of glacial deposits. In conclusion, sea-floor spreading can be evidenced through Paleomagnetism and glacial deposits since they explain the mechanics of this process and how it explains continental drift.