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Harry Hess proposed the seafloor spreading hypothesis in 1960 (published in 1962 [1]); the term "spreading of the seafloor" was introduced by geophysicist Robert S. Dietz in 1961. [2] 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. [3]
Spreading rate is the rate at which an ocean basin widens due to seafloor spreading. (The rate at which new oceanic lithosphere is added to each tectonic plate on either side of a mid-ocean ridge is the spreading half-rate and is equal to half of the spreading rate). Spreading rates determine if the ridge is fast, intermediate, or slow.
It is now thought seafloor spreading at the Havre Trough started about 5.5 to 5.0 million years ago in response to the rollback of the subducting Pacific Plate and terminated abruptly about 3.0 to 2.5 million years ago [7] In the western Havre Trough the evidence for historic seafloor spreading is believed to have resulted from the initial ...
Prior to the deep sea drilling program, the ages of the oceanic basalt were estimated based on magnetic lineations generated at the spreading center as the sea floor pulled apart. Sediments immediately overlying the basalt should have ages similar to the age of magnetic stripes.
Evidence from paleomagnetism led to the revival of the continental drift hypothesis and its transformation into the modern theory of plate tectonics. Apparent polar wander paths provided the first clear geophysical evidence for continental drift, while marine magnetic anomalies did the same for seafloor spreading .
Frederick John Vine FRS (17 June 1939 – 21 June 2024) was an English marine geologist and geophysicist.He made key contributions to the theory of plate tectonics, helping to show that the seafloor spreads from mid-ocean ridges with a symmetrical pattern of magnetic reversals in the basalt rocks on either side.
Robert Sinclair Dietz (September 14, 1914 – May 19, 1995) was a scientist with the United States Coast and Geodetic Survey.Dietz, born in Westfield, New Jersey, [1] was a marine geologist, geophysicist and oceanographer who conducted pioneering research along with Harry Hammond Hess concerning seafloor spreading, published as early as 1960–1961.
In the late 1960s, geophysicists working with new technologies of marine magnetic surveying and earthquake seismology proved the operation of seafloor spreading, devised explanations with the new concepts of plate tectonics, and showed that ocean floors and mobile continents jointly formed tectonic plates. Hamilton was a pioneer in showing how ...