Greinar (Vísindafélag Íslendinga) - 01.01.1976, Page 117

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Iceland stable zone with the aquatories lying to the north, and especi-
ally, to the south of it, where very large horizontal displacements of
the lithosphere are supposed to he (48)? The problem stays open,
since these territories were outside the research program of the Soviet
Geodynamic Expedition. It should be hoped that the structure and
history of the Norwegian and Greenland basins, on the one side,
and the Reykjanes Ridge, on the other, were analysed anew in the
light of the facts observed on land in Iceland and on the immedia-
tely aquatories. Too often lately attempts were made to understand
the structui'e of land areas by the interpretation of oceanic struc-
ture. We think that the reverse regard from land into the ocean can
prove, at any rate, no less productive. The discrepancy between
the supposed age of the magnetic anomalies on the submarine
Reykjanes ridge with the age of volcanic rocks on the continuation
of these anomalies on land in Iceland has been emphasised previ-
ously (13). These facts should be given due attention.
Everything considered, a conclusion might be drawn that Ice-
land is not just bottom lifted above sea level. Walking in Iceland
with a geological hammer in hand, we tread not on the basalts that
were once covering ocean bottom. The rifts of Iceland, no doubt,
continue the rifts of the Mid-Atlantic Ridge, but in the form in
which they penetrated through the thick crust of continental origin.
The relationship between the mid-ocean ridge and the land struc-
tures here is somewhat similar to that observed at the transition of
the rift of the Mid-Indian Ridge onto the land in East Africa.
There is a difference between these cases, however, i.e. the crust of
Iceland already is not typical continental crust, it acquired certain
new features, which brought it somewhat closer to the oceanic type.
Consequently, the region described above is hardly suited for
serving as the basis for demonstrating continental drift. But it seems
extremely favomable for the study of the mechanism causing the
subsidence of blocks of the continental crust below sea level, their
basification and oceanisation. In Northern Atlantic and in the sur-
rounding regions of the Arctic Ocean different stages of this process
could be observed and studied. That is the reason why this area
should be considered with attention by researches in future as well.