Environmental Engineering Reference
In-Depth Information
CRYONIVAL (SNOW AND ICE) BELT
The alpine zone is a glacial-cryonival-slope landsystem experiencing high energy and
sediment transfers (Figure 25.16). It is best developed in areas of intense Pleistocene
alpine glaciation which excavated deep glacial troughs, tributary
cirques
and
oversteepened rockwalls. Considerable volumes of debris were plastered indiscriminately
or as retreat moraines on lower slopes during deglaciation. Rock wall and moraine-
covered slopes are fully integrated into the alpine landsystem, which reworks this glacial
'inheritance' (Plate 25.6). The continuing role of modern alpine glaciers and mountain ice
caps is covered in Chapter 15. Glaciers promote active denudation but their meltwater
and sediment transfers may partially bypass the alpine slope system where glaciers
terminate below the regional timberline. Their presence 'insulates' subglacial surfaces
from other alpine processes but actively promotes them at their perimeter (especially in
supraglacial rock walls) by influencing radiation, moisture and wind aspects of the
topoclimate.
Figure 25.16
A mountain landsystem, identifying (1)
cryonival zone of snow, ice and permafrost, (2) rock walls
and rockwall processes, (3) degraded slopes and former
high-level valley floors and benches, (4) active lower slopes
and (5) valley floor system. Source: Fookes (1997).
