Sea-floor Spreading It’s tearing me apart! The Idea Sea-floor spreading is the process in which the ocean floor is pulled outwards when two plates move apart. As the plates move apart, the rocks break and form a crack between the plates. Magma rises through the cracks and seeps out onto the ocean floor. The Man Born in 1906 Became a professor of geology at Princeton in 1932 He commanded a submarine base during World War II In 1960 he hypothesized that the sea-floor was spreading from vents (underwater holes) in a rift found in the Atlantic Ocean The Evidence During WWII, his mission was to study the deepest parts of the ocean floor • Until this time, scientists believed the sea-floor was completely flat! The Evidence Hundreds of flat topped mountains in the Pacific Ocean Great Global Rift in the Atlantic Ocean In his own words. It was possible that molten magma from beneath the earth's crust could ooze up between the plates in the Great Global Rift. As this hot magma cooled in the ocean water, it would expand and push the plates on either side of it -- North and South America to the west and Eurasia and Africa to the east. This way, the Atlantic Ocean would get wider but the coastlines of the landmasses would not change dramatically.