Theory of Plate Tectonics

By ACoyne
  • Continental Drift

    A man named Alfred Wegner hypothesised that around 500 million years ago all contenents where joined together in one super continent, which he named Pangaea. He said the continent came to their present locations from a process called Contenental drift. He could not prove how the contenents moved so his hypothesis was rejected.
  • Mantle Drives Continental Drift

    Arthur Holmes hypothesised that continental drift was driven by the mantle, at the time his idea was thought to be silly.
  • Magnetic Patterns, 1950s

    Magneotometers where used to detect magnetic variations on the ocean floor, going in stripes of polarity and reverse polarity
  • Discovery of Mid-Ocean Ridges

    Seismic and depth recorders developments in the 1950s led to the discovery of mid-ocean ridges
  • Sea-floor Spreading

    Henry Hess and Robert Dietz came up with the idea of sea-floor spreading. This is when magma comes up from mid-ocean ridges making new sea floor and the old sea floor sinks back into the mantle at ocean trenches.
  • Glomar Challenger

    This vessel explored the mid-ocean ridge between Africa and South America and obtained samples proving the youngest ocean floor is located near the ridges, and oldest is located around continents.
  • Theory of Plate Tectonics

    After all the evidence, we have finally reached this theory that the crust is broke into large sections called plates that move around and spread.