The idea of continental drift has since been subsumed by the theory of plate tectonics, which explains that the continents move by riding on plates of the Earth's lithosphere. == History == === Early history === Abraham Ortelius , Theodor Christoph Lilienthal (1756), Alexander von Humboldt (1801 and 1845), Antonio Snider-Pellegrini , and others had noted earlier that the shapes of continents on opposite sides of the Atlantic Ocean (most notably, Africa and South America) seem to fit together.
Dana was enormously influential in America—his Manual of Mineralogy is still in print in revised form—and the theory became known as the Permanence theory. This appeared to be confirmed by the exploration of the deep sea beds conducted by the Challenger expedition, 1872–1876, which showed that contrary to expectation, land debris brought down by rivers to the ocean is deposited comparatively close to the shore on what is now known as the continental shelf.
This led Mantovani to propose a now-discredited Expanding Earth theory. Continental drift without expansion was proposed by Frank Bursley Taylor, who suggested in 1908 (published in 1910) that the continents were moved into their present positions by a process of "continental creep", later proposing a mechanism of increased tidal forces during the Cretaceous dragging the crust towards the equator.
This led Mantovani to propose a now-discredited Expanding Earth theory. Continental drift without expansion was proposed by Frank Bursley Taylor, who suggested in 1908 (published in 1910) that the continents were moved into their present positions by a process of "continental creep", later proposing a mechanism of increased tidal forces during the Cretaceous dragging the crust towards the equator.
The Polflucht hypothesis was also studied by Paul Sophus Epstein in 1920 and found to be implausible. === Rejection of Wegener's theory, 1910s–1950s === Although now accepted, the theory of continental drift was rejected for many years, with evidence in its favor considered insufficient.
The concept was independently and more fully developed by Alfred Wegener in 1912, but his hypothesis was rejected by many for lack of any motive mechanism.
For a time in the mid-20th century, the theory of continental drift was referred to as the "Taylor-Wegener hypothesis" Alfred Wegener first presented his hypothesis to the German Geological Society on 6 January 1912.
His hypothesis was that the continents had once formed a single landmass, called Pangaea, before breaking apart and drifting to their present locations. Wegener was the first to use the phrase "continental drift" (1912, 1915) (in German "die Verschiebung der Kontinente" – translated into English in 1922) and formally publish the hypothesis that the continents had somehow "drifted" apart.
The Polflucht hypothesis was also studied by Paul Sophus Epstein in 1920 and found to be implausible. === Rejection of Wegener's theory, 1910s–1950s === Although now accepted, the theory of continental drift was rejected for many years, with evidence in its favor considered insufficient.
In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force.
His hypothesis was that the continents had once formed a single landmass, called Pangaea, before breaking apart and drifting to their present locations. Wegener was the first to use the phrase "continental drift" (1912, 1915) (in German "die Verschiebung der Kontinente" – translated into English in 1922) and formally publish the hypothesis that the continents had somehow "drifted" apart.
In particular, the English geologist Arthur Holmes proposed in 1920 that plate junctions might lie beneath the sea, and in 1928 that convection currents within the mantle might be the driving force.
Various attempts to explain this foundered on other difficulties. == Road to acceptance == From the 1930s to the late 1950s, works by Vening-Meinesz, Holmes, Umbgrove, and numerous others outlined concepts that were close or nearly identical to modern plate tectonics theory.
He proposed in 1931 that the Earth's mantle contained convection cells which dissipated heat produced by radioactive decay and moved the crust at the surface.
In 1939 an international geological conference was held in Frankfurt.
Bernauer thought this extension had drifted the continents only 100–200 km apart, the approximate width of the volcanic zone in Iceland. David Attenborough, who attended university in the second half of the 1940s, recounted an incident illustrating its lack of acceptance then: "I once asked one of my lecturers why he was not talking to us about continental drift and I was told, sneeringly, that if I could prove there was a force that could move continents, then he might think about it.
Worse, the most viable forms of the theory predicted the existence of convection cell boundaries reaching deep into the earth that had yet to be observed. In 1947, a team of scientists led by Maurice Ewing confirmed the existence of a rise in the central Atlantic Ocean, and found that the floor of the seabed beneath the sediments was chemically and physically different from continental crust.
Various attempts to explain this foundered on other difficulties. == Road to acceptance == From the 1930s to the late 1950s, works by Vening-Meinesz, Holmes, Umbgrove, and numerous others outlined concepts that were close or nearly identical to modern plate tectonics theory.
The idea was moonshine, I was informed." As late as 1953—just five years before Carey introduced the theory of plate tectonics—the theory of continental drift was rejected by the physicist Scheidegger on the following grounds. First, it had been shown that floating masses on a rotating geoid would collect at the equator, and stay there.
In a series of papers in 1959–1963, Heezen, Dietz, Hess, Mason, Vine, Matthews, and Morley collectively realized that the magnetization of the ocean floor formed extensive, zebra-like patterns: one stripe would exhibit normal polarity and the adjoining stripes reversed polarity.
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