Jökull - 01.12.1985, Blaðsíða 17

Fig. 6. Suggested glacial terminal zon-
es in Adalvík. Zones A and B are
inferred from shallow banks, zone C
from lateral terraces at the northern
and southern parts of Adalvík, and
zone D from terminal moraines on
land. Map base: Icelandic Hydro-
graphic Survey, pilot chart 46 (ísa-
fjardardjúp). 6. mynd. Áœtluð lega
jökuljaðars í Aðalvík á mismunandi
tíma. Belti A og B eru áætluð út frá
grynningum á hafsbotni, belti C út frá
jaðarhjöllum og belti D út frá jökul-
görðum á landi.
level at section 3, which supports the kettlehole
concept.
Most of the lower part of the valley inside Haelavík,
above the 26—27 m limit, is characterized by a well
developed hummocky topography. It can be followed
along the valley up towards the outer limits of the area
covered by ice during the Little Ice Age, in the Fannar-
lág cirque at the head of the valley.
In summary, the geological data from Haelavík indi-
cate: (1) That at the time when the lateral deposits on
the eastern side of Haelavík were deposited the Haela-
yík glacier was at least 150 m thick near the present
coastline. According to the low marine limit its terminus
was probably grounded. The lower till in section 1 was
most probably deposited by this glacier. (2) The retreat
of the glacier to inside the present coastline took place
when sea level stood at least above the present 5—8 m
level, as indicated by the silt covered waterlain part of
the lower till. (3) Then the glacier readvanced, deposit-
ed the upper till in section 1 and contorted the under-
lying silt. This glacier was about 55 m thick at the
present coastline, judged by the altitude of the lateral
terrace on the eastern side of Haelavík, which repre-
sents the youngest ice advance there. The supraglacial
till in sections 2 and 3 must represent this last glacier
advance. (4) There was then a regression of the sea
from the 26—27 m marine limit to below the 1 m level,
as evidenced by deposition of lacustrine/fluvial sedi-
ments on top of the till in section 3.
Hlöduvík: Along the coast of eastern Hlöduvík there
is an about 10 m high cliff, partly overgrown but well
exposed along some stretches. Two separate units are
exposed in this section. The lower one is a till and the
upper one a predominantly coarse-grained beach sedi-
ment. The till is boulder rich, compact and silty, similar
to the tills exposed in section 1 at Haelavík. There is a
concentration of very large boulders (SH m diameter) at
the western part of the section; these may derive from a
medial moraine. Only one till bed is found, and the
surface of it has been abraded by a sea standing 10—15
JÖKULL35. ÁR 15