Search results
Results from the WOW.Com Content Network
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.
Open ocean convection is a process in which the mesoscale ocean circulation and large, strong winds mix layers of water at different depths. Fresher water lying over the saltier or warmer over the colder leads to the stratification of water, or its separation into layers. Strong winds cause evaporation, so the ocean surface cools, weakening the ...
In 1953, the cartographer Marie Tharp generated the first three-dimensional relief map of the ocean floor which proved there was an underwater mountain range in the middle of the Atlantic, along with the Mid-Atlantic Ridge. [7] The survey data was large step towards many more discoveries about the geology of the sea. [6]
Magnetic anomalies off west coast of North America. Dashed lines are spreading centers on mid-ocean ridges. The Vine–Matthews-Morley hypothesis correlates the symmetric magnetic patterns seen on the seafloor with geomagnetic field reversals. At mid-ocean ridges, new crust is created by the injection, extrusion, and solidification of magma.
In physical oceanography, Langmuir circulation consists of a series of shallow, slow, counter-rotating vortices at the ocean's surface aligned with the wind. These circulations are developed when wind blows steadily over the sea surface. Irving Langmuir discovered this phenomenon after observing windrows of seaweed in the Sargasso Sea in 1927. [1]
Arthur Holmes proposed the more plausible mechanism of mantle convection, [16] which, together with evidence provided by the mapping of the ocean floor following the Second World War, led to the development and acceptance of the theory of plate tectonics. This theory provides the widely-accepted explanation for the existence and breakup of Pangaea.
Of the 71 percent of the Earth’s surface that is ocean floor, only 26 percent of it has been mapped with the level of resolution used on this expedition by the institute.
Despite this, changes in the global sea level over the past 3–4 billion years have only been a few hundred metres, much smaller than the average ocean depth of 4 kilometres. Thus, the fluxes of water into and out of the mantle are expected to be roughly balanced, and the water content of the mantle steady.