Erdpyramiden (also called "Erdpfeiler") are steep, tower or conical erosion form of relatively easily erodable rock (z. B. weakly cemented sandstone , loess , boulder clay , volcanic tuff ), which complete by resting blocks of less erodible material before Removal has been preserved so far.
Preconditions for the formation of earth pyramids are certain properties of the material (relative fine-grainedness, low, but not too low consolidation ), the climate (regular precipitation), a location sheltered from the wind and the occurrence of larger stones or boulders made of erosion-resistant solid rock ( e.g. igneous rock or gneiss ) in the fine-grained material. In many cases, the parent rock is therefore Pleistocene boulder clay or boulder clay .
The formation takes place as follows:
- The starting point for the formation of earth pyramids is the exposure of a sediment body with corresponding properties on a relatively steep slope.
- Rainwater that runs off the surface cuts deep furrows (flushing grooves that widen into gullies ) in the slope or the sediment body. Individual blocks of solid rock, which occur naturally in the eroding sediment body, protect the underlying, fine-grained material. As a result, this erodes much more slowly than unprotected material. More or less high columns of fine-grained sediment remain below such a stone, among other things because the sheltered location ensures that rain can only attack directly from above.
- If a pillar loses its capstone, it then erodes relatively quickly. It takes on the shape of a sugar loaf and gets smaller and smaller until it finally disappears completely. Meanwhile, new earth cones are forming further up on the slope ( receding erosion ).
Examples of earth pyramids
Earth pyramids are found worldwide; Examples of earth pyramids are:
- Renon earth pyramids near Bozen ( South Tyrol )
- Earth pyramids of Steinegg , municipality of Karneid (South Tyrol)
- Earth pyramids in Percha near Bruneck (South Tyrol)
- Earth pyramids near Terenten , municipality of Terenten (South Tyrol)
- Earth pyramids of Segonzano ( Trentino )
- Earth pyramids in the Cilento Natural Park , southeast of the Italian coastal town of Marina di Camerota
- Earth pyramids of Zone (Lombardy)
- Ciciu del Villar , Villar San Costanzo (Piedmont)
- Earth pyramids near Serfaus am Arlberg
- Earth pyramids in Schönberg ( Tyrol )
- Earth pyramids near Arzl im Pitztal (Tyrol)
- Earth pyramids of Euseigne in Val d'Hérémence ( Canton of Valais )
- Earth pyramids in Schanfigg near Arosa ( Canton of Graubünden )
- Fairy chimneys in Turkey
- Hans Becker: About the emergence of earth pyramids (= news from the Academy of Sciences in Göttingen. Mathematical-physical class. 1963, No. 12, ). Vandenhoeck & Ruprecht, Göttingen 1963.
- Hans Becker: Comparative consideration of the formation of earth pyramids in different climatic areas of the earth (= Cologne geographical works. Vol. 17, ). Geographical Institute of the University of Cologne, Cologne 1962 (At the same time: Cologne, University, dissertation, from June 23, 1962).