Cycle theory

The theory of cycles is the assumption that the development of the earth took place in cycles in geological time periods. Between 1910 and 1926, Hans Stille dealt with the alternation between calm evolution and increased events ( revolution ).

At the beginning of a geotectonic cycle there is epirogenesis , usually as a lowering of a geosyncline . In the active part of the cycle, the geosyncline is unfolded into a mountain range ( orogenesis ), then it subsides again with subsequent uplift and later erosion . A geomagnetic cycle can run parallel to this ( synorogenic ) .

In the 1930s it was found that six such cycles of vigorous orogeny had occurred since the Cambrian . They show (according to Bubnoff 1954) common processes: transgression (s) - inundation (flooding of land areas) - strong facies - formation - regression and emersion (land uplift). However, it is difficult to prove whether such cycles also existed in the Precambrian .

literature

• H.Murawski and W.Meyer, Geological Dictionary . 11th edition, Spektrum Akademischer Verlag 2004
• H.Hölder, Brief History of Geology , Springer-Verlag 1989.