Continental Drift and Plate Tectonics

2637 WordsFeb 14, 201311 Pages
Continental Drift and Plate Tectonics Theory (Part 1a) Introduction: The Beginning of the “Continental Drift Theory” In the middle of the eighteenth century, James Hutton proposed a theory, uniformitarianism; “the present is the key to the past”. It held that processes such as geologic forces- gradual and catastrophic-occurring in the present were the same that operated in the past. (Matt Rosenberg, 2004) This theory coincides with the theory of Continental Drift that was first proposed by Abraham Ortelius in December 1596, who suggested that North, South America, Africa and Eurasia were once connected but had been torn apart by earthquakes and floods. He also discovered that the coasts of the eastern part of South America and the…show more content…
Water from the south then flowed in over time, thus forming the evaporites now found along the coastlines there. (Lois Van Wagner, 2013)(Figure 5) However, Wegener believed that only the continents were moving and they plowed through the rocks of the ocean basins. (Colliers Encyclopedia, 1996) Harold Jeffreys then argued that it is impossible for continents to break through solid rock without breaking apart. (USGS, 2012) Wegener also claimed that the centrifugal force of the spinning planet had forced the continents sideways, parallel to the equator; tidal pull from the sun and moon had caused lateral movement. (Sant, Joseph, 2012) His orders of magnitude were too weak. Thus, his theory was dismissed. (Lois Van Wagner, 2013) Further development and support of the “Continental Drift Theory” in the 1960s After World War 2, the U.S. Office of Naval Research intensified efforts in ocean-floor mapping, leading to the discovery of the Mid-Atlantic Ridge to be part of a continous system of mid-oceanic ridges on all ocean floors, prompting Harry H. Hess to suggest the theory of sea-floor spreading. The oldest fossils found in ocean sediments were only 180 million years old and little sediment were accumulated on the ocean floor. Thus, he suggested that seafloors were no more than a few hundred million years old, significantly younger than continental land due to
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