Greinar (Vísindafélag Íslendinga) - 01.01.1935, Page 77

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eyri seems to have been about 170 metr.es thick, and the
thickness of the ice-cap would of course be much more
at the centre of the glaciers. Very shortly before the
Akureyri-stage the relative positions of land and sea
were very much the same as they are now, and
according to the theory of isostasy the glaciers in Ice-
land ought at that time, or a little before, to have had
a very similar extension to what they have now. I was
unable to find anything at Akureyri which eould give
information about the temperature conditions at that
period, either in the sea or in the air. On the other
hand, G. G. Bárðarson inferred from his observations
at Saurbær that the sea was arctic cold at that time (i. e.
previous to the Akureyri-stage), and that the glaciers
covered the land right down to the sea. It is not possible
to reconcile this view with the theory of isostasy. Either
some of the cold-loving species of shells which Bárðar-
son found there belong to another period than he as-
sumed, or else some other factors than isostasy have at
this time had most effect on the relative positions of
land and sea in Iceland.
Shortly after the glaciers of the Akureyri-stage began
to retreat the re-elevation of the land began, and this
upheaval of the land seems to follow rather closely the
diminishing of the glaciers, at least the shore-line seems
to have reached to about the same position as at present
by nine thousand years ago. After the disappearance of
the glaciers the effect of their weight lasted therefore
only for a period of about one thousand years at the out-
most. The present raising of the land in Northern Sweden
is usually regarded as an after effect of the last glaciers
there, and the effects of the pressure of the glacier seem
therefore to have been felt much longer there than in Ice-
land. This may be explained, at least partly, by the fact that
Iceland is a volcanic country, and for this reason is in closer
connection with the magma than the Scandinavian pen-
insula which is built up of granites and gneisses. Ice-
land is also by far less extensive and the disturbance of