when was the theory of seafloor spreading proposed
1960s
title: Seafloor spreading text: Seafloor spreading Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Earlier theories (e.g. by Alfred Wegener and Alexander du Toit) of continental drift postulated that continents "ploughed" through the sea. The idea that the seafloor itself moves (and also carries the continents with it) as it expands from a central axis was proposed by Harry Hess from Princeton University in the 1960s. The theory is well accepted now, and the phenomenon is known to be caused by convection currents in the title: Vine–Matthews–Morley hypothesis text: Vine–Matthews–Morley hypothesis The Vine–Matthews–Morley hypothesis, also known as the Morley–Vine–Matthews hypothesis, was the first key scientific test of the seafloor spreading theory of continental drift and plate tectonics. Harry Hess proposed the sea-floor spreading hypothesis in 1960 (published in 1962 ); the term "spreading of the seafloor" was introduced by geophysicist Robert S. Dietz in 1961 . According to Hess, seafloor was created at mid-oceanic ridges by the convection of the earth's mantle, pushing and spreading the older crust away from the ridge. Geophysicist Frederick John Vine and the Canadian geologist Lawrence W. Morley independently realized that if Hess’s seafloor title: Seafloor spreading text: ~ Tx/L, where L is the distance between the ridge to the continental shelf (roughly half the ocean width), and T is the ocean age. Seafloor spreading Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. Earlier theories (e.g. by Alfred Wegener and Alexander du Toit) of continental drift postulated that continents "ploughed" through the sea. The idea that the seafloor itself moves (and also carries the continents with it) as it expands from a central axis was proposed by Harry Hess title: Vine–Matthews–Morley hypothesis text: latitudes, north-south trending ridges at all latitudes, and east-west trending ridges at the magnetic equator. Vine–Matthews–Morley hypothesis The Vine–Matthews–Morley hypothesis, also known as the Morley–Vine–Matthews hypothesis, was the first key scientific test of the seafloor spreading theory of continental drift and plate tectonics. Harry Hess proposed the sea-floor spreading hypothesis in 1960 (published in 1962 ); the term "spreading of the seafloor" was introduced by geophysicist Robert S. Dietz in 1961 . According to Hess, seafloor was created at mid-oceanic ridges by the convection of the earth's mantle, pushing and spreading the older crust away from the ridge. Geophysicist Frederick title: Plate tectonics text: Admiral, and Robert S. Dietz, a scientist with the U.S. Coast and Geodetic Survey who first coined the term "seafloor spreading". Dietz and Hess (the former published the same idea one year earlier in "Nature", but priority belongs to Hess who had already distributed an unpublished manuscript of his 1962 article by 1960) were among the small handful who really understood the broad implications of sea floor spreading and how it would eventually agree with the, at that time, unconventional and unaccepted ideas of continental drift and the elegant and mobilistic models proposed by previous workers like Holmes. In the