Jökull - 01.12.1970, Page 35

glacial streams carried water directly from the
ice front into channel 43 and this system acted
as the principal drainage route between Jökuls-
árlón and Breidárlón until at least 1961.
Between 1937 and 1945 several channels (51)
which had been established parallel to the front
of Fjallsjökull were abandoned and the pro-
glacial lake Fjallsárlón became the focus of the
drainage system carrying water from the west-
ern margin of Breidamerkurjökull and the east-
ern margin of Fjallsjökull.
1945-51 (Fig. 6)
There were no really significant develop-
ments in the drainage system during this
period. The proglacial lakes continued to grow
in size as the ice front retreated and all the
meltwaters were carried out to the coast by
means of the five main rivers: Fjallsá, channel
49, channel 43, the Jökulsá and the Stemma.
The Jökulsá at this time occupied only one
channel instead of the two occupied in 1945.
1951-1960/1 (Fig. 7)
East of the Jökulsárlón this period represents
the termination of the general south-eastward
movement of meltwaters so typical of 1945—51
and the development of drainage either par-
allel to the ice front or back into the icp
These developments were the result of the er:
posure by ice wastage of topography with a
dominant slope towards the ice front. A series
of channels (25, 26, 27, 28 and 29) draining
towards the Jökulsárlón were formed between
1954 and 1960. Channel 27 is only one metre
wide and its position on a surface sloping to-
wards the glacier indicates that it was probablv
formed submarginally. The main channel in
this area (25) was produced between 1959 and
1961 (Fig. 8). Channel 26, which in parts is
12 m wide and 6 m deep, had been abandoned
in 1959 but water flowed through channel 25
in both 1960 and 1961, although it took slight-
ly different courses in the two years flowing
marginally and submarginally to the glacier.
East of the Stemma river channel 3, which
is approximately 20 m wide, carried meltwaters
at least until 1954. Channel 2 carried melt-
waters directly away from the glacier but ceas-
ed to function when drainage moved parallel
to the ice front along channel 1. Between
1955 and 1961 drainage from the eastern ice
front became increasingly concentrated towards
the Stemma system and by 1961 the upper
Stemmulón had begun to develop.
West of the Jökulsárlón, both channels 49
Fig. 5.
JÖKULL 20. ÁR 33