Geology Reference
In-Depth Information
Table 9. 5.
Tentative rates of denudation due to avalanche activity in glacial cirques on Svalbard. From André (1993).
Avalanche Activity
Annual mean 1983-85
Surface (m 2 )
Volume (m 3 )
Number (%)
Weight (kg)
(a) Steep cirque wall in massive gneisses. Area: 145 000 m 2
Debris-free avalanches
21 (65%)
5800
0
0
Slightly dirty avalanches
9 (26%)
1300
390
0.12
Moderately dirty avalanches
2 (6%)
310
1 530
0.5
Highly dirty avalanches
1 (3%)
50
1 030
0.4
Total
33 (100%)
7460
2 950
1.0
(b) Cirque wall in densely fractured mica-schist. Area: 135 000 m²
Debris-free avalanches
8 (14%)
1400
0
0
Slightly dirty avalanches
26 (48%)
4200
1 250
0.4
Moderately dirty avalanches
16 (29%)
2600
13 000
4.8
Highly dirty avalanches
5 (9%)
760
15 200
5.6
Total
55 (100%)
8960
29 450
10.8
Rate of denudation in massive gneiss: 0.007 mm/year
Rate of denudation in fractured mica-schist: 0.08 mm/year
 
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