Terrace crossing
A terrace crossing is a change in the positional relationship of two or more river terraces when the river flows from an uplift area into a subsidence area.
In an uplift area, due to the increased erosion of the river into the uplifting area, the oldest terraces are in a higher position on the slope than the younger ones. In a subsidence area, relief is compensated by increased accumulation of river sediments. Older sediments are sunk underground and covered by younger terrace sediments. At the transition between uplift and active subsidence areas, terraces of different ages intersect. These processes illustrate why, with the help of the altitude of river terraces (morphostratigraphy) in tectonically active areas, it is fundamentally impossible to make any reliable statements about the age of the terraces. Stratigraphic correlations are usually only possible by comparing the heavy mineral spectra .
A typical example of a terrace crossing can be found on the Rhine , at the transition from the currently rising Rhenish Slate Mountains to the active subsidence area of the Lower Rhine Bay . Several terrace crossings can be observed here on the section of the Rhine from Düsseldorf to Arnhem .
Individual evidence
- ^ Karl N. Thomé: Introduction to the Quaternary: the age of the glaciers. Springer, Berlin 1998, ISBN 3-642-58744-5 , p. 198.
- ↑ Josef Klostermann: The climate in the ice age . E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 1999, ISBN 3-510-65189-8 , pp. 74ff., 144f.
- ↑ Josef Klostermann: The climate in the ice age . E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 1999, ISBN 3-510-65189-8 , p. 76.