Jökull - 01.12.1983, Page 91

Fig.3. Alpine landscape and coastal clifls in Iceland. 1. Cross hatched areas show the part of the country
where erosional forms of alpine glaciers predominate, or approximately 26,000 km2. 2. Marine eroded fjord
promontories and wave cut cliífs higher than 60 to 80 m are shown with broad, broken lines.
Mynd 3. Alpalandslag og sjávarhamrar á íslandi. Skástrikuðu svæðin syna þá hluta landslagsins, þar sem rofform
alpajökla eru ríkjandi, en það eru um 26.000 km2. Sjávarrofnir fjarðarmúlar og brimklif hterri en 60 til 80 m eru synd
með breiðum, hökuðum línum.
mountain landscape which existed before their
formation. Above the glaciation limit snow and ice
collect on top of the mountain peaks and on their
flanks, and collapse as avalanches and ice-falls to
the corries and valleys, where the ice and snow are
welded together as an homogeneous mass, which
creeps downslope. The valley glaciers flow along the
main valleys and are constantly added to by tribut-
ary glaciers and overfull corries in the valley sides
continuing until ablation equilibrium is reached. If
the ablation is insufficient to melt the ice before the
snout has emerged from the valleys (fjords), it ex-
tends in all directions forming a piedmont glacier,
such as Múlajökull in Hofsjökull does today, and
this rapidly increases the ablation area.
Thegeomorphology due to alpine glaciation (Fig.
1) is predominantly a sharpening and enlarging of
the ffuvially eroded landforms which preexisted at
each glaciation, rather than the creation of a new
landscape. It is characterised therefore by serrated
ridges, horns, corries, throughs or fjords which are
often excavated more deeply than the land in front
of them. The formation of a piedmont glacier has
only a minor eflect on this development, since the
erosional capability of a glacier decreases very rap-
idly as it spreads outwards.
Those areas in Iceland, where alpine landforms
are predominant, are shown in Fig. 3. Glacier form-
adon there has thus been theresultofthe pre-glacial
landscape. There is no reason to suppose that these
areas have at any time been covered by very thick
ice sheets, because they would be bound to have left
very distinct erosional traces, since the erosional
capability of glaciers increases very quickly with
increasing ice thickness. Many of the alpine areas
shown on Fig.3 have been located inbetween two
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