Geology Reference
In-Depth Information
Table 9.6.
Summary data on rates of cliff recession under periglacial and non-periglacial
conditions.
Location
Lithology
Recession
Source
(mm/year)
(i) Periglacial - high latitude:
Mt Templet, Spitsbergen
Limestone and sandstone
0.34-0.50
Rapp (1960b)
Mt Langtunafjell,
Limestone and sandstone
0.05-0.50
Rapp (1960b)
Spitsbergen
Longyeardalen, Spitsbergen
0.3
Jahn (1976)
Spitsbergen, Kongsfjord
Massive gneiss
0.007
André (1993)
Fractured mica-schist
0.08
Spitsbergen, Wijdefjord
Amphibolite
0.03-0.11
André (1993)
Spitsbergen, Ossian
Quartzite
0.1-1.5
André (1993)
Sarsfjellet
Northern Lapland,
Schists
0.04-0.15
Rapp (1960a)
Karkevagge
Ellesmere Island, NWT,
Dolomitic limestone
0.30-1.30
P. Souchez; personal
Canada
communication (1971)
Yukon, Canada
Syenite, diabase
0.003-0.019
Gray (1973)
(ii) Periglacial - alpine:
Austrian Alps
Gneiss, schist
0.7-1.0
Poser, in Rapp (1960a)
Swiss Alps
2.5
Barsch (1977)
Canadian Rockies
Limestone
0.06-0.26
Luckman (1972)
(iii) Non-periglacial:
Mt St Hiliaire, PQ, Canada
Gabbro, breccia
0.02-0.04
Pearce and Elson (1973)
Brazil
Granite
2.0
Quoted in Young (1972)
South Africa
Granite
1.5
Quoted in Young (1972)
Southwest USA
Shale
2-13
Quoted in Young (1972)
effects of snowmelt are complicated by the presence of impermeable frozen sediments at
the base of the active layer.
Slopewash in periglacial environments has often been linked to the concept of nivation
(Matthes, 1900). The latter is a vague term associated with the frost shattering, gelifl uc-
tion, and slopewash processes thought related to late-lying seasonal snow. In its simplest
form, nivation was seen as a suite of snow-bank-induced erosional processes that are
thought to erode hollows, cirque-like basins, or benches (Cook and Raiche, 1962; Kariya,
2002; Nyberg, 1991; St-Onge, 1969). This causal relationship between snow banks and
landforms does not always stand up to rigorous analysis because many fi eld measurements
now demonstrate the lack of effective freeze-thaw cycles beneath snow banks (Thorn,
1976, 1979a, b; Thorn and Hall, 1980). As a result, modern usage of the term is not gener-
ally recommended (Thorn, 1988; Thorn and Hall, 2002). Having stated this, it remains
true that an understanding of snow-bank hydrology is an essential requirement if one
wishes to assess the signifi cance of slopewash processes.
9.6.1. Snow-Bank Hydrology
The distribution of snow in any one area is largely controlled by prevailing winds and
topography. It is also a major control over the ground-thermal regime (see Chapter 5) and
 
Search WWH ::




Custom Search