Glacial erosion
87
northwest of Scotland and of the Canadian and Baltic Sea shield areas (Sugden, 1978;
Gordon, 1981; Rea and Evans, 1996). Glacial sedimentation is characterized by small
discontinuous and thin till sheets. Another form developed in these circumstances,
although not exclusive of them, is the crag and tail form consisting of an extended "tail of
till" located down the icestream from the hill crag. The observations of Jahns (1943)
concerning this type of relief indicate that erosion of a hill is more important when
shielded from the ice flow. This author arrived at this conclusion by the erosion
experienced by sheeting structures previous to the passing of the glacier.
2.7. Fjords
Fjord is a Norwegian term used for a long and deep sea arm characterized by more or less
straight segments, steep walls and very great depths (Fairbridge, 1968a).The longest fjords
are Norvestfjord/Scores by Sund in Greenland (230 km), Sognefjord in Norway (220 km)
and Greely Fjord/Nansen Sound in the Canadian arctic (400 km) (Evans, 2004b). They are
located along high latitude coasts (Figs. 3.26 and 3.27), and are characterized by a
threshold at the outlet, totally or partially submerged, and by a deep fjord basin inside
(Syvitski et al., 1987). The threshold is generally rocky and basins can reach enormous
depths. The greatest depth measured is in a basin 1288 m deep in Messier Channel (Chile),
but it is possible that some of those existing in Antarctica reach 2000 m (Andrews, 1975).
As indicated by several authors, some fjord areas (Eastern Canadian Arctic, Greenland,
Norway and New Zeeland) present a clear structural control, a cause adduced by some
Figure 3.26. Geiranger Fjord, Norway.
87
northwest of Scotland and of the Canadian and Baltic Sea shield areas (Sugden, 1978;
Gordon, 1981; Rea and Evans, 1996). Glacial sedimentation is characterized by small
discontinuous and thin till sheets. Another form developed in these circumstances,
although not exclusive of them, is the crag and tail form consisting of an extended "tail of
till" located down the icestream from the hill crag. The observations of Jahns (1943)
concerning this type of relief indicate that erosion of a hill is more important when
shielded from the ice flow. This author arrived at this conclusion by the erosion
experienced by sheeting structures previous to the passing of the glacier.
2.7. Fjords
Fjord is a Norwegian term used for a long and deep sea arm characterized by more or less
straight segments, steep walls and very great depths (Fairbridge, 1968a).The longest fjords
are Norvestfjord/Scores by Sund in Greenland (230 km), Sognefjord in Norway (220 km)
and Greely Fjord/Nansen Sound in the Canadian arctic (400 km) (Evans, 2004b). They are
located along high latitude coasts (Figs. 3.26 and 3.27), and are characterized by a
threshold at the outlet, totally or partially submerged, and by a deep fjord basin inside
(Syvitski et al., 1987). The threshold is generally rocky and basins can reach enormous
depths. The greatest depth measured is in a basin 1288 m deep in Messier Channel (Chile),
but it is possible that some of those existing in Antarctica reach 2000 m (Andrews, 1975).
As indicated by several authors, some fjord areas (Eastern Canadian Arctic, Greenland,
Norway and New Zeeland) present a clear structural control, a cause adduced by some
Figure 3.26. Geiranger Fjord, Norway.