Plate Tectonics
The earliest hint of plate tectonics was made around 1800 by one of Abraham G. Werner's most famous student, the German naturalist and explorer Alexander von Humboldt (1769–1859). Humboldt first suggested that the South American and African continents had once been joined, as apparent in their complimentary coastlines, but this proposal was largely ignored by the scientific community of that time. It would not be until the early 20th Century, in 1912, when the German astronomer, meteorologist and geophysicist Alfred Wegener (1880–1930) published his first works (Die Entstehung der Kontiente, Petermanns Mitteilungen, 1912, pp. 185–195, 253–256, and 305–309; and a somewhat different version with the same title in Geologische Rundschau, Vol. 3, No. 4, 1912, pp. 276–292) outlining his theory of "continental drift". After 1912, Wegener's work was interrupted first by an expedition to Greenland and then by the First World War. In 1915 Wegener published the first edition of Die Entstehund der Kontinente und Ozeane (The Origin of Continents and Oceans). In this book Wegener claimed that the continents had once been connected and formed a single supercontinent mass called Pangaea (from the Greek for "all the Earth"), about 300 million years ago,which had since split into pieces that have drifted to their present positions. As supporting evidence for the proposed theory Wegener noted the often matched large-scale geological features on separated continents, such as the close similarity of strata and fossils between Africa and South America and the close fit between their coastlines,and that fossils found in certain places often indicated past climates utterly different from today’s. Wegener’s revolutionary theory of continental drift took decades to win general acceptance among scientists, remaining controversial until the 1960's. For most of that lapse of time stratigraphy was to stand still, with no significant progress. In 1959 and 1962, Harry Hammond Hess proposed the sea-floor spreading or plate tectonics theory, subsequentely confirmed by Vine and Matthews (1963), which complemented Wegener's continental drift theory, and gave a much needed renewed impetus into the science of stratigraphy. Nevertheless, Wegener's basic insights remain sound nowadays and the same lines of supporting evidence are being continuously complemented and expanded by ongoing research.
