|
The evolution of tectonophysics is closely linked to the history of the continental drift and plate tectonics hypotheses. The continental drift/ Airy-Heiskanen isostasy hypothesis had many flaws and scarce data. The fixist/ Pratt-Hayford isostasy, the contracting Earth and the expanding Earth concepts had many flaws as well. The idea of continents with a permanent location, the geosyncline theory, the Pratt-Hayford isostasy, the extrapolation of the age of the Earth by Lord Kelvin as a black body cooling down, the contracting Earth, the Earth as a solid and crystalline body, is one school of thought. A lithosphere creeping over the asthenosphere is a logical consequence of an Earth with internal heat by radioactivity decay, the Airy-Heiskanen isostasy, thrust faults and Niskanen's mantle viscosity determinations. ==Introduction== First there was the Creationism (Martin Luther), and the age of the Earth was 6000 years. There were stacks of calcareous rocks of maritime origin above sea level, and up and down motions were allowed (geosyncline hypothesis, James Hall and James D. Dana). Later on, the thrust fault concept appeared, and a contracting Earth (Eduard Suess, James D. Dana, Albert Heim) was its driving force. In 1862, the physicist William Thomson (who later became Lord Kelvin) calculated the age of Earth (as a cooling black body) at between 20 million and 400 million years. In 1895, John Perry produced an age of Earth estimate of 2 to 3 billion years old using a model of a convective mantle and thin crust. Finally, Arthur Holmes published ''The Age of the Earth, an Introduction to Geological Ideas'' in 1927, in which he presented a range of 1.6 to 3.0 billion years. Wegener had data for assuming that the relative positions of the continents change over time. It was a mistake to state the continents "plowed" through the sea, although it isn't sure that this fixist quote is true in the original in German. He was an outsider with a doctorate in astronomy attacking an established theory between 'geophysicists'. The geophysicists were right to state that the Earth is solid, and the mantle is elastic (for seismic waves) and inhomogeneous, and the ocean floor would not allow the movement of the continents. But excluding one alternative, substantiates the opposite alternative: passive continents and an active seafloor spreading and subduction, with accretion belts on the edges of the continents. The velocity of the sliding continents, was allowed in the uncertainty of the fixed continent model and seafloor subduction and upwelling with phase change allows for inhomogeneity. The problem too, was the specialisation. Arthur Holmes and Alfred Rittmann saw it right . Only an outsider can have the overview, only an outsider sees the forest, not only the trees . But A. Wegener did not have the specialisation to correctly weight the quality of the geophysical data and the paleontologic data, and its conclusions. Wegener's main interest was meteorology, and he wanted to join the Denmark-Greenland expedition scheduled for mid 1912. So he hurried up to present his Continental Drift hypothesis.〔 Mainly Charles Lyell, Harold Jeffreys, James D. Dana, Charles Schuchert, Chester Longwell, and the conflict with the Axis powers slowed down the acceptance of continental drifting . * Abraham Ortelius (cited in ), Francis Bacon (cited in ), Theodor Christoph Lilienthal (1756) (cited in , and in Schmeling, 2004), Alexander von Humboldt (1801 and 1845) (cited in Schmeling, 2004〔), 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 (see also , and ). * *Note: Francis Bacon was thinking of western Africa and western South America and Theodor Lilienthal was thinking about the sunken island of Atlantis and changing sea levels. * * Catastrophism (e.g. Christian Fundamentalism, William Thomson) vs. Uniformitarianism (e.g. Charles Lyell, Thomas Henry Huxley) . * * Term coined by William Whewell. * * Uniformitarism is the prevailing view in the U.S. . * Charles Lyell assumed that land masses changed their location, but he assumed a mechanism of vertical movement . James Dwight Dana assumed a permanent location as well, influencing the American fixist school of thought . It wasn't known that the seafloor isn't mainly granite rock (sial) (as the continental cratons) but mainly basalt rock (sima). * * Quote, Lyell: "Continents therefore, although permanent for whole geological epochs, shift their positions entirely in the course of ages." ( cited in ) * * Quote, Wallace about Dana: "In 1856, in articles in the American Journal, he discussed the development of the American continent, and argued for its general permanence; and in his Manual of Geology in 1863 and later editions, the same views were more fully enforced and were latterly applied to all continents." ( cited in ) * Pratt's isostasy is the prevailing view : * * Airy-Heiskanen Model; where different topographic heights are accommodated by changes in crustal thickness. * * Pratt-Hayford Model; where different topographic heights are accommodated by lateral changes in rock density. * * Vening Meinesz, or Flexural Model; where the lithosphere acts as an elastic plate and its inherent rigidity distributes local topographic loads over a broad region by bending. * A cooling and contracting Earth is the prevailing view. * * H. Jeffreys was the most important contractionist , - * H. Wettstein , E. Suess, Bailey Willis and Benjamin Franklin allow horizontal move of the Earth's crust. * * . But Willis was a fixist, as he supported the permanent position of the oceans, although he didn't believe in land-bridges . * * * * Quote, Benjamin Franklin (1782): "The crust of the Earth must be a shell floating on a fluid interior.... Thus the surface of the globe would be capable of being broken and distorted by the violent movements of the fluids on which it rested".〔:s:en:Franklin to Abbé Jean-Louis Giraud Soulavie〕 *The vertical movement of Scandinavia after the ice age is accepted (recent average uplift c. 1 cm/year). This implies a certain plasticity under the crust . * *The alpine geology with its theory of thrusting (as geosyncline hypothesis; today's thrust tectonics) accepted horizontal movements. cited in *1848 Arnold Escher shows Roderick Murchison the Glarus thrust at the Pass dil Segnas. But Arnold Escher does not publish it as a thrust as it contradicts the geosyncline hypothesis. * Eduard Suess proposed Gondwanaland in 1861, as a result of the Glossopteris findings, but he believed that the oceans flooded the spaces currently between those lands. And he proposed the Tethys Sea in 1893. He came to the conclusion that the Alps to the North were once at the bottom of an ocean . *The idea of continental drifting shows up for the first time. John Henry Pepper merges Antonio Snider-Pellegrini's map, Evan Hopkins' proof of northward shifting of the continents of his neptunist book and his plutonism ( and cited in ). * 1884, Marcel Alexandre Bertrand interpretes the Glarus thrust as a thrust. * * *Hans Schardt demonstrates that the Prealps are allochthonous. * * * * * * * 1907, thrust faults get established: Lapworth, Peach and Horne working on parts of the Moine Thrust, Scotland. * * * * * *Director-Generals of the British Geological Survey: Roderick Murchison (1855–1872) and Archibald Geikie (1881–1901) * Although Wegener's theory was formed independently and was more complete than those of his predecessors, Wegener later credited a number of past authors with similar ideas:〔 , 〕 Franklin Coxworthy (between 1848 and 1890), Roberto Mantovani (between 1889 and 1909), William Henry Pickering (1907) and Frank Bursley Taylor (1908). * * 1912-1929: Alfred Wegener develops his continental drift hypothesis. (, ) *In the 1920s Earth scientists refer to themselves as drifters (or mobilists) or fixists . Terms introduced by the Swiss geologist Émile Argand in 1924 . *Moreover, most of the blistering attacks were aimed at Wegener himself, an outsider (PhD in Astronomy) who seemed to be attacking the very foundations of geology. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Timeline of the development of tectonophysics (before 1954)」の詳細全文を読む スポンサード リンク
|