Continental drift is the movement of the
Earth's
continents relative to each other. The hypothesis that continents 'drift' was first put forward by
Abraham Ortelius in 1596 and was fully developed by
Alfred Wegener in 1912. However, it was not until the development of the theory of
plate tectonics in the 1960s, that a sufficient
geological explanation of that movement was understood. (This article gives an overview about the development of the continental drift hypothesis before 1950. For the contemporary theory, see the article
plate tectonics.)
Abraham Ortelius in his work Thesaurus Geographicus ... suggested that the Americas were "torn away from Europe and Africa ... by earthquakes and floods" and went on to say "The vestiges of the rupture reveal themselves, if someone brings forward a map of the world and considers carefully the coasts of the three [continents].
The hypothesis that the continents once formed a single landmass, broke up, and drifted to their present locations was fully elaborated by Alfred Wegener in 1912. [2] Although Wegener's theory was formed independently and was more complete than those of his predecessors, Wegener would later credit a number of past authors with similar ideas [3] [4] Franklin Coxworthy (between 1848 and 1890), [5] Roberto Mantovani (between 1889 and 1909), William Henry Pickering (1907) [6] and Frank Bursley Taylor (1908).
For example The similarity of southern continent geological formations had led Roberto Mantovani to conjecture in 1889 and 1909 that all the continents had once been joined into a supercontinent (now known as Pangaea). (Regarding the former positions of the southern continents, Wegener himself also noted the similarity of Mantovani's and his own maps). Through volcanic activity because of thermal expansion this continent broke, whereby the new continents were drifting away from each other because of further expansion of the rip-zones, where now the oceans lie. However, this led Mantovani to propose an Expanding Earth theory, which is now considered to be superseded. [7] [8] [9] Some sort of continental drift at constant earth radius was proposed by Frank Bursley Taylor, who suggested in 1908 (published in 1910) that the continents were dragged towards the equator by increased lunar gravity during the Cretaceous, thus forming the Himalaya and Alps on the southern faces. Wegener said that from all those theories, Taylor's theory (although not fully developed) had the most similarities to his own theory. [10]
