Greinar (Vísindafélag Íslendinga) - 01.01.1977, Side 16

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termed the Hólkot Stage (2), and on vague ground claimed to
correspond to the northern margin of the Younger Dryas „main
glacier“ covering Iceland.
As we have already stated, there is undoubted correspon-
dence in time between the main climatic periods in Iceland,
and Scandinavia, periods of the order of 1000 years duration.
But it is too much to expect every short-periodic fluctuation
of the Scandinavian retreating glacier to have a correspond-
ing glacier fluctuation in Iceland — but just on that assump-
tion, Þórarinsson bases his claim that the Hólkot Stage cor-
responds to Younger Dryas. However, it is well known that
short-periodic weather fluctuations are often opposite in the
two places.
Þórarinsson’s dating is, moreover, doubtful in two respects.
First, the Hólkot Stage could rather be of Older Dryas age,
and correspond to the southern rand of a local glacier on the
cluster of mountains on high ground north and northeast
of Mývatn. This alternative becomes attractive when the con-
clusions are based on such basic factors of climatology as
climate, the height of the terrain, and the origin of the pre-
cipitation. This local glacier would correspond to that of Blá-
f jallajökull, Fig. 4.
On the other hand, the assumption of the Younger Dryas rand
in the Mývatn area, makes the extension of the glacier from
the glacier divide between Vatnajökull and Mýrdalsjökull, twice
as broad in the precipitation shadow as on the precipitation
side, an inconsistency that cannot be explained away by point-
ing out the great asymmetry of the Scandinavian continental
glacier, as we shall point out below.
And now we come to another fundamental factor which makes
Pleistocene glaciations of Iceland incomparable with those of
Scandinavia. In Scandinavia, there is only one chain of mountains
on which a glaciation will begin and end, whereas in Iceland there
are many such mountain chains and clusters of mountains on
which a glaciation can and must begin, more or less simult-
aneously, and end similarly as a number of separate glaciers.