The present lesson will provide a brief outline of approaches used and attempts made to quantitatively model the chain of mass exchange processes. It will also give an overview of the main soil types in mountainous areas and the factors influencing the evolution of soils.

Mass transportation in cold mountain areas takes place at a rather steady rate in the form of small-scale rock falls, snow avalanches, glacier movement, permafrost creep, solifluction and river flow. Large-scale rock falls, landslides, floods and debris flows, however, reflect more rarely occurring extreme events (Figure 1). In the context of the present overview, the term "cold mountain area" is applied to the periglacial and glacial belts of regions with a rugged topography and considerable altitudinal extent. Within long time intervals such as the Holocene or the Quaternary, even low-frequency/high-magnitude events are part of a dynamic equilibrium and thereby represent a basic risk for life, settlements and installations in cold mountain areas. The main question is whether and, if yes, to what extent this historic situation has changed already and may chang further in the future.
During the past few decades, the most remarkable changes in cold mountain geomorphology have largely been caused by the increased human activities with respect to traffic, communication, hydropower production, tourism, military defense, hazard protection, etc. as well as by the fast icemelt due to rising atmospheric temperatures. The coming decades could see an acceleration of this tendency leading to the development of conditions without historic or holocene precedent. Such a scenario would affect all parts of the highly sensitive cold mountain ecosystem (e.g. hydrological cycle, cryosphere components, growth conditions, landscape appearance). It would also demand that developmental planning no longer be based on historical/empirical knowledge but rather on an improved understanding of the involved processes in combination with robust models applicable to practical cases.

Soils need hundreds or even thousands of years to reach their climax, especially in high mountain areas. They develop through percolation of water, mineral weathering, eluviation and accumulation of oxides and hydroxides, clay minerals, humic acids, etc. Whenever slope stability diminuishes and rocks and sediments start to move (caused by climatic or human impact), the time clock of soil evolution is generally set to zero and the corresponding processes must start over, as soon as the slopes are stabilized. Therefore, soil development and the distribution of different soil types are closely related to slope processes.

29 August 2011
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