Plate tectonics: Difference between revisions
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'''Plate tectonics''' in geology is | '''Plate tectonics''' in geology is a [[scientific theory]] based on movements of distinct "plates" of the crustal layer of the [[earth]], which can explain surface and undersea features such as mountain ranges and deep-sea trenches. As such it is a theory broad in scope, accounting for many geological features previously understood piecemeal. | ||
Conventionally the earth has 3 major layers: [[crust]] - the outermost layer, [[mantle]] and [[core]]. Until the early 1960s, with the exception of a very few people such as Alfred Wegener and [[Arthur Holmes]], most scientists believed the continents and seas to be largely unchanged, with the exception of such things as vertical crustal movements which formed mountain ranges and [[weather erosion]]. Formation of mountains was then understood by the [http://www.uwgb.edu/DutchS/platetec/geosync.htm geosyncline concept] which had been elaborated in the latter 19th century. | |||
The theory was | Arguments for an early "super-continent" which split apart over eons were put forward by [[Alfred Wegener]], a German physicist born in 1880, in his book [http://caliban.mpiz-koeln.mpg.de/~stueber/wegener/text/IMG_4853.html ''Die Entstehung der Kontinente und Ozeane''] (''The Origin of Continents and Oceans'' - first edition 1915). His theory was based on several significant coincidences which, taken together, convinced him that the continents had split apart from an enormous land mass he called [[Pangaea]] (translated: whole earth), which he believed existed millions of years in the past. Among the coincidences he was trying to explain was the way the shapes of continents seemed to fit together, for example [[Africa]] to [[South America]]. | ||
Wegener elaborated the theory of [[continental drift]], which assumed that the continents 'plowed' through the oceans, and can be considered a precursor to modern plate tectonics. .. | |||
==Refs== | ==Refs== | ||
Revision as of 03:29, 21 November 2007
Plate tectonics in geology is a scientific theory based on movements of distinct "plates" of the crustal layer of the earth, which can explain surface and undersea features such as mountain ranges and deep-sea trenches. As such it is a theory broad in scope, accounting for many geological features previously understood piecemeal.
Conventionally the earth has 3 major layers: crust - the outermost layer, mantle and core. Until the early 1960s, with the exception of a very few people such as Alfred Wegener and Arthur Holmes, most scientists believed the continents and seas to be largely unchanged, with the exception of such things as vertical crustal movements which formed mountain ranges and weather erosion. Formation of mountains was then understood by the geosyncline concept which had been elaborated in the latter 19th century.
Arguments for an early "super-continent" which split apart over eons were put forward by Alfred Wegener, a German physicist born in 1880, in his book Die Entstehung der Kontinente und Ozeane (The Origin of Continents and Oceans - first edition 1915). His theory was based on several significant coincidences which, taken together, convinced him that the continents had split apart from an enormous land mass he called Pangaea (translated: whole earth), which he believed existed millions of years in the past. Among the coincidences he was trying to explain was the way the shapes of continents seemed to fit together, for example Africa to South America.
Wegener elaborated the theory of continental drift, which assumed that the continents 'plowed' through the oceans, and can be considered a precursor to modern plate tectonics. ..