Jökull - 01.12.1999, Page 68

Figure 9. The steep snout of the southern part of
Höfðabrekkujökull. — Brattur sporður suðurhluta
Höfðabrekkujökuls.
Other glaciofluvial forms
Kames, eskers, kame terraces, proglacial river deltas
and bottoms of drained, ice-dammed lakes should also
be included among the forms of glaciofluvial accumu-
lation within the study area. These forms occur spo-
radically and fragments of kame terraces preserved
only in the northern and southern part of the forefield
deserve attention (Figure 11). The kame terrace lo-
cated about 4.5 km from the glacier snout, west of the
Sandvatn basin and beyond the oldest end moraines,
has a 10 m high exposure made up of a series of lay-
ered fine-grained sands and silts deposited in a stag-
nant or slow-flowing water. Favourable conditions
for the creation of proglacial ice-dammed lakes and
kame terraces also existed in the northern part of the
marginal zone.
Forms linked with erosive activity of meltwaters
This group includes erosional cuts at the glacier snout,
melt-water outflow channels, erosional meltwater
plains, dry channels, river gorges and canyons, wa-
terfall thresholds, lava thresholds on outwash plains,
slopes and ledges. Of these forms, erosive meltwa-
ter surfaces are most extensive. They mainly appear
in the form of sheets north of the Hafursey massif,
near the 1890-1900's end moraines, where they are
flat and covered with morainic pavement or gravelly-
stony formations, resulting from the washing away of

Figure 10. Preserved fragments of ground moraine
protruding beyond the surface of present-day progla-
cial cones. — Mœlistika við leifar af botnurð sem
stendur upp úr yngri sandi. Fjær sést í Hvol-, Rem-
undargils-, og Vatnsrásarhöfuð.
finer material. The remaining erosive forms generated
by meltwaters mainly occur in the northern part of the
glacier forefield.
Kettles generated by melting of iceblocks
Normal and rimmed kettles are observed exclusively
on outwash plains. They often occur in concentrations
forming a pitted surface. Rimmed kettles from the
1918 jökulhlaup are only found in the southem part
of the marginal zone, west of Hafursey (Olszewski
and Weckwerth, this issue). They are relatively shal-
low, up to a dozen metres in diameter, surrounded by
a 0.5-1.5 m high, sandy-gravelly-stony ridge. Some-
times rock blocks up to 2 m in diameter are embedded
in them.
Nival forms
These forms include niveofluvial valleys and under-
slope proluvial cones. Niveofluvial valleys are gen-
erated by the erosive activity of snowmelt, with the
participation of denudational processes, mainly creep
and flowage of the weathering cover. Consequently
they have a concave base with a gentle outline. They
principally develop on rocky massifs, in single or
branched forms, line on top of Hafursey, where they
reach a length of up to 2 km. Their course is often
dependent on the surface relief of the structure.
66 JÖKULL, No. 47