Jökull - 01.12.1984, Blaðsíða 128

and concluded that the moist south-westerly
winds and the short distance from the sea enabled
glacier growth below 1000 m altitude in
Skardsheidi. Keilhack (1886) described large
snowfields at the locality described by Ólafsson
(1772), and found it interesting that a cirque-gla-
cier should begin to grow prior to any visible
signs of glacier growth at the higher elevated
plateaux. He suggested that the Skardsheidi
plateau was large enough to sustain its own ice-
cap, given favourable circumstances. Thoroddsen
(1891, 1958) described two small glaciers in
Skardsheidi above Skorradalur and discussed
their sensitivity to climatic variations. According
to Thoroddsen (1958) the glaciers were very small
during the warm and dry summer of 1888, but
grew considerably during the wet summer of
1890, at which time the glaciers reached down
below 300 m altitude. During the first decade of
the 20th century the Skardsheidi glaciers seem to
have melted rapidly. According to Bárdarson
(1934) the Skardsheidi glaciers had retreated to
above 800 m altitude by 1910. Eythorsson (1931)
only found traces of these glaciers. Bárdarson
(1934) and Thorarinsson (1943) surveyed the
literature concerning the glaciers and commented
on their oscillations.
DISCUSSION
When reviewing the geological literature on
the Late Weichselian of the Borgarfjördur
region, it is evident that many problems have
remained unsolved or controversial. The lithos-
tratigraphy of the area is not well known, and
formal lithostratigraphical division of the sedi-
ments has not been proposed for any part of the
sequence. The work of Bárdarson (1923) does
not meet modern requirements for quantitative
methods or precision. The sections described by
Ashwell (1967, 1975) and Ingólfsson (1981) need
to be reexamined with the aim of lithostra-
tigraphical correlation between different parts of
the region. Most workers have only visited the
region briefly, and their observations are often
casual and difficult to correlate in order to form a
concise picture of the Late Weichselian glacia-
tion. The chronostratigraphy of the region can
only be considered preliminary as the radiocar-
bon dates on which it is based (Table 1) only date
a small part of the sequence. A detailed chronos-
tratigraphical scheme for the sequence is there-
fore lacking. The sea level changes in the region
are not well known and only a few careful levell-
ings of ancient shore lines have been carried out.
Bárdarson’s evidence for two transgressions in
the region has not been reexamined, and correla-
tions of sea levels with sections of the strata are
fragmentary and often controversial. Reconstruc-
tions of palaeoenvironments are contradictory
and have not been integrated with any facies
analysis of the sediments. The existence of tills or
other glacial deposits is a matter of dispute. A
detailed geological map of the region has not
been compiled, and the surface extent of the
various sediments is not well known.
CONCLUSIONS
The literature reviewed in this paper gives
clear indication of the vast sedimentary deposits
in the Borgarfjördur region, and some insight
into the many aspects involved concerning the
interpretation of their formation and environ-
ments of deposition. The lack of detailed know-
ledge of the stratigraphy allows for various
interpretations of the Late Weichselian processes
in the region.
Further research has potential significance in
two interconnected fields of research: Firstly it
can contribute to a more solid model of the Late
Weichselian glaciation than presently exists for
Western Iceland, and can as such have implica-
tions for the general picture of glacial geology in
Iceland. Secondly it can contribute to the intense
scientific debate on the Weichselian glacier varia-
tions in the North Atlantic region (for discussion
see e.g. Andrews and Barry 1978, Boulton 1979,
Hughes et al. 1981, Hjort 1981, Andersen 1981,
Ruddiman and Mclntyre 1981, Funder 1982,
Boulton et al. 1982, Salvigsen and Österholm
1982). As Iceland lies geographically in the mid-
dle of the North Atlantic region, it could be
expected to contribute valuable evidence on the
topic of Late Weichselian glaciations in the
region. But the incomplete stratigraphical control
of the available data in Iceland renders the value
of the Icelandic contribution somewhat limited.
ACKNOWLEDGEMENTS
7 arn indebted to the following people for their
assistance: Professor Th. Einarsson, for initiating
the research project of which this paper is a part,
126 JÖKULL 34. ÁR