COntinental drift
...oticing the distinctive resemblance in coastline structure and how one can ponder that the continents were once connected. Evidence of fossils of ancient plants and animals along the coasts and the geological strata of the continents showed some conformity with the continents. There were many skeptics that said there were large gaps and some areas of overlapping land. But in 1965 Sir Edward Bullard answered the question on whether or not it was possible that the continents could fit together. He used an electronic computer programmed to find the best and any possible arrangements for the two continents. The contour line at a depth of 1000 meters fit the best. Even though overlapping and gaps did exist they were relatively small and could be disregarded. It was until this experiment that they had conclusive evidence of the possibility of the continents fitting together. Bullard later concluded that the continents were once one supercontinent. In 1968 P. Hurley created his own method. Hurley and his colleagues knew that there were numerous geological features on both coastlines. They were able to fit the two continents together by gathering rocks and other geological features and figuring out their ages by the radio metric method. Hurley and his crew studied all kinds of rocks from the coastlines along Africa and South America. These rocks were dated in two different time periods. Some were around 600 million years old and others were around two billion years old! The rocks match according to their age across the coasts where they would have met if they were connected. After all this evidence was gathered people started taking the continental drift theory more seriously. Fitting the continents together was understood, but how or what could have separated the supercontinent? The whole point behind the theory of continental drift is meaningless if they can’t find the cause. Wegener knew this so he had to come up with something. He speculated that the continents moved away from the poles, which they were at and drifted towards the equatorial region. Wegener believe the Earth’s rotation on it’s axis creates a centrifugal force is what creates the continents to drift towards the equator. He called this the pole-fleeing force. Other scientist argued that this force wasn’t capable of moving the continents. Even thought this force was several million times smaller than gravity, Wegener still believe that over a great amount of time this force is capable of moving a continent. Wegener also had another theory that scientist criticized. This theory was based on the tidal attraction of the sun and the moon. Even though Wegener had all these theories he never was able to prove it. In the early 1960s the theory of sea-floor spreading was introduced. Robert Dietz and Harry Hess were the first two people who came up with this theory. Till this day there is controversy on who came up with the theory first. Dietz’s theory was published first but around the same time, even though his book was not yet published, Hess’s hypothesis was well known. The idea behind sea-floor spreading is that where is mountain range approximately 64,000 km long and 1000 km wide. They called these underwater mountain ranges mid-ocean ridges. Mid-ocean ridges resulted from the upwelling flows of rising magma from the mantle. When the magma rises up to the crust, the crust breaks up releasing the hot magma then cooling into the ocean to form new oceanic crust. Thus the seafloor then spreads laterally from these mid-ocean ridges. While the seafloor is spreading, it releases magnetic particles, which allows scientist to determine how old the seafloor is. This magnetic measurement method helped scientist figure out that the youngest crust on Earth is in the center of the spreading mid-ocean ridges. This baffled geologists for centuries. They never understood why the seafloor was only around 150 million years old, verses the 4.6 billion year old Earth. It would seem logical that the ocean had the oldest crust; evidently this is not the case. The farther away from the middle of the mid-ocean ridges the older the seafloor got. The ocean floor is continuously renewing itself, creating new crust and continuously changing. The older crust farther from the spreading mid-ocean ridges is being buried by the newer, ...