Sea Floor Spreading Forms the Best Evidence for Continental Drift

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Sea floor spreading forms the best evidence for continental drift. Critically discuss this statement. There is lots of evidence to support the theory of continental drift, including Harry Hess’s discovery of sea floor spreading theory. By using sonar, Hess found that oceans were shallower in the middle, allowing him to identify Mid Ocean Ridges. He suggested that at the centre of oceans, molten material would rise from the Earth’s mantle, causing new sea floor to be created, pushing the ocean floor. He also suggested that there were ocean trenches where old sea floor would then go back into the mantle, and molten. He found that these ocean trenches, the deepest parts of the ocean, were very near continental plates. Hess theorized that the action of the sea floor spreading caused continents to move apart and so this being evidence for continental drift, showing why it happened. The evidence of sea floor spreading was further supported by Vine and Drummond, who studied the magnetic pattern of the sea floor. They found that the Earth’s magnetic field changes over time, because as magma from the mantle rises to the crust it cools but the basalt will align to the field it cools to. It is also found that on either side of mid oceanic ridges there were symmetrical magnetic patterns, so suggesting that the ocean was created at the mid oceanic ridges and as new ocean floor cooled, it pushed the crust away. Both Hess and Vine and Drummond found evidence that is crucial to the explanation of how continental drift happened, and it is very important in the development of geologists understanding, however other people found evidence to support continental drift also. Dan McKenzie went on to further explain sea floor spreading, being able to explain why new crust was made at mid oceanic ridges. He used his knowledge of thermodynamics to come up with a model of the
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