"" (U.S. Dept. Geology www) Wegener's first ideas for his theory, "Continental Drift- (Schwarzbach p.81), came from his observations between the similarities of various fossils in South America and Africa and the similarities of South America's east coastline with Africa's west coastline. He hypothesized the continents at some time where one landmass. "Pangaea- (U.S. Geological Survey www), is the name for the landmass, before the Dinosaur era, before all the Continents hypothetically split to their current dimensions. In Wegener's hypothesis he likened-- the continents moved like the icebergs floated on water. Wegener found the Continents are made of lighter rock, granite and the crust, beneath the Continents, when pressurized, the heat makes that rock fluid-like and the Continents move on that material. For years, after Wegener went public with the idea of Continental Drift, his theory was scrutinized throughout the science world, but ironically Wegener's theories for "Continental Drift- would become the basis for the science of Tectonics. .
The idea of Plate Tectonics' from Alfred Wegener's continental drift theory developed further from Robert S. Dietz and Harry Hess "the idea of sea-floor spreading'. Drummond Matthews and Frederick Vines tied together the earth's magnetic forces with continental movement. Grahame J.H. Oliver and B. Isacks postulated the idea of subduction'. They changed the terminology from continental drift to, "Global Tectonics "continents moving.""(Schwarzbach p.122).
In the Atlantic Ocean there exists a mid-Atlantic ridge, an area between two plates where magma is forcing continents to drift apart. The result is the development of new ocean floor. This concept is sea-floor spreading', first postulated in the 1950's by Harry H. Hess, a Geologist and Naval Reserve Admiral and Robert S. Dietz, a Scientist with U.S. Coast Geodetic Survey. There are several ridges running through the ocean floors, they act as outlets for lava from the earth's mantle.
