Geology Reference
In-Depth Information
Sub-sea
permafrost
Alpine
permafrost
Continuous
permafrost
Discontinuous
permafrost
Figure 11.1
Distribution of permafrost in the Northern Hemisphere. Isolated areas of alpine permafrost, which are not
shown, are found in high mountains of Mexico, Hawaii, Japan, and Europe.
Source:
Adapted from Péwé (1991)
landform initiation and evolution (Thorn 1992). It
comes in a variety of forms (Table 11.1):
soil ice
(needle
ice, segregated ice, and ice filling pore spaces);
vein ice
(single veins and ice wedges);
intrusive ice
(pingo ice and
sheet ice);
extrusive ice
, which is formed subaerially, as
on floodplains;
ice fromsublimation
, which is formed in
cavities by crystallization from water vapour; and
buried
ice
(buried icebergs and buried glacier ice) (Embleton
and King 1975b, 34). Some ground ice lasts for a day,
forming under present climatic conditions, some of it
