Relief reversal
Relief reversal (also: inversion ) is the morphological transformation of tectonic forms through the removal of differently resistant rocks. Saddles and clumps become morphological depressions, hollows and ditches become elevations.
Requirements for the relief reversal
The following illustrations make the principle clear.
Deposition and development of rock layers of different hardness
Until the Mesozoic , large areas of today's mainland were covered with sea. The rivers of the mainland transported different materials into the sea in the coastal areas in different epochs. In the lower layers mostly soft sandstones , clays and marls were deposited . Harder clay layers and ferrous rock followed. The tropical climate at that time promoted limestone formation in the shallow sea regions and very hard reef rocks formed as the top layer .
The presence of a tectonic hollow
Earth movements and stretching forces could create tectonic hollows at weak points in the earth's crust. Relief reversal is not possible without such a depression.
Relief inversion process
Removal of the rock layers outside the hollow
As the sea slowly retreated, the tectonic hollows initially formed a natural protection against erosion by wind and flowing water. As a result, the rock layers outside the hollow were slowly eroded over millions of years, while the hard rock inside the hollow could hardly be attacked. After the hard rock outside the basin had been removed, the erosion in the softer rock there proceeded even faster, so that the former basin slowly reversed to the hill.
Faster erosion through soft rock layers
With the complete siltation, wind and weather now also attacked the rock layers within the former hollow. However, this very hard rock was able to offer much greater resistance to erosion than the soft rock strata in the wide area. This made the surrounding area lower and lower. A topographical elevation has thus arisen from the geological hollow.
Well-known examples
- Leuchtenburg (Seitenroda) near Kahla
- Ratberg and Ratberggraben near Magstadt
- Ulrichsberg near Klagenfurt
- Scheibenberg , Pöhlberg and Bärenstein in the Ore Mountains
- Montagne de la Serre and Gergovia Plateau near Saint-Saturnin (Puy-de-Dôme) , France
- Lots of elevations in the central Great Valley of the Appalachians
Web links
Individual evidence
- ↑ Herbert Louis: General Geomorphology: Text part and separate picture part. Walter de Gruyter, 2013, p. 339.
- ↑ H. Bluhm et al. a .: Monuments in the neighborhood - seen and visited in the Böblingen district. Sindelfingen 1990.
- ↑ Friedhelm Thiedig, Gudrun Frohnert: The Ulrichsberg - a relief reversal: Geological structure and geological development of the "mons carantanus" on the outskirts of Klagenfurt. In: Carinthia II . 198/118 Year, Klagenfurt 2008, pp. 47–82 ( PDF on ZOBODAT ).
- ↑ Local website