Solifluction stage
The solifluction stage or periglacial elevation stage in high mountains refers to a geomorphological altitude level below the snow line that extends over several 100 meters in altitude and is free of snow in summer and in which, for climatic reasons, the processes of frost-related weathering and soil erosion predominate or determine the shape.
Transferred to the ecological vegetation levels, the solifluction level partly includes areas of the subalpine heights, the entire alpine and subnival heights. It therefore lies between the deeper collin montane vegetation levels - in which chemical and fluvial (caused by flowing water) shaping processes predominate - and the frost debris and glacier level - in which the glacial morphology is dominant.
A periglacial step occurs in all high mountains between the subarctic and the inner tropics , with the exception of the high mountains of the Earth's dry belt .
It is characterized by a periglacial climate and the slow "flow" of thawed soils ( solifluction ). In landscapes that were formerly shaped by the periglacial climate in the Quaternary, geological remnants may have been preserved, which, like the boulder seas and boulder streams, are also found in today's low mountain ranges.
Mark
geomorphology
The solifluction stage starts below the snow line and is characterized by frost-related weathering, permafrost and solifluction with the resulting debris and block heaps . It is mostly free of snow in summer (however, depending on the exposure and the small relief, firn and snow fields can occur all year round). The main geomorphological processes are frost weathering and soil flow due to thawing and freezing of water-saturated soil substrates. These are referred to as solifluction, which is referred to as unbound solifluction in ungrown frost debris and as bound solifluction in substrates overgrown with vegetation. The unbound solifluction is a noticeable landscape element, especially in mountains with sedimentary rocks, since limestones and especially dolomite in locations comparable to silicate mountains are characterized by the rubble character of the subsoil. Characteristics are long-lasting snow cover, noticeable meltwater influence and, in addition to the long-lasting water saturation of the soil, cryoturbation and solifluction. Soil formation processes are continually disrupted by water or wind, solifluction, rubble slides and rock falls. The soil development therefore usually does not go beyond the preliminary stages of mature soils, at least in limestone mountains with strong relief.
Individual evidence
- ^ Carl Rathjens 1982: Geography of the high mountains: 1. The natural space . Teubner Study Books of Geography, Teubner, Stuttgart. ISBN 3-519-03419-0 Here p. 97f.
- ↑ Spectrum Lexicon of Geography: Periglacial Height Limits Periglacial Height Limits .
- ↑ Spectrum Lexicon of Geography: Bolckmeer Blockmeer .
- ↑ Werner Bätzing : Small Alpine Lexicon. Environment - economy - culture. CH Beck, Munich 1997, ISBN 3-406-42005-2 , pp. 104-108.
- ↑ Spectrum Lexicon of Geography: Periglacial Periglacial .
- ↑ Thorsten English: Multivariate analyzes of the syn systematics and site ecology of the snow floor vegetation (Arabidetalia caerulea) in the Northern Limestone Alps. In: Stapfia. Volume 59, Linz 1999, ISSN 0252-192X, p. 56, PDF on ZOBODAT
- ↑ Thorsten English 1999: p. 45.