Greinar (Vísindafélag Íslendinga) - 01.01.1977, Page 43

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Now, at last, there is full harmony between morphology and
the age of the sediments.
We mentioned earlier the possibility of submergence of the
Active Zones in Iceland. We now see that the horizontal zonal
dolerites are of Upper Pliocene age, and the formation of the
zones may not be much earlier. Hence, we can probably not
expect any great thickness of marine sediments under the
zonal dolerites, nor any prolific marine life. The chances of oil
seem then not to be great.
But the outlook is quite different in connection with the
Tjörnes deposits. They were formed after the great Bárðar-
dalur faulting, i.e. on the subsided east side of the fault. The
displacement is greatest in the north but gradually declines
towards the south. The Tjörnes deposits eould at most reach
into the neighbourhood of Kálfborgará, where the underlying
basalts emerge. In the area Aðaldalur, we could expect to find
the marine deposits gradually thickening towards the shore of
Skjálfandi and farther northwards into the bay. Around Húsa-
vík they might also be thick. And the prolific marine life in
the warm Lower Pliocene or earlier sea, may certainly have
produced oil, not least the Cardium Groenlandicum division.
Moreover, there is a fracture zone from Húsavík to Flatey,
right through the sediments, in which oil reservoirs could be
expected. The basalts between Hallbjarnastaðakambur as well
as the Breiðavík Upper Pliocene deposits, could have formed
a roof over such reservoirs. The depth down to the Cardium
division in the Skjálfandi Bay could be estimated, as soon as
sparker measurements have located the basalt floor under the
Breiðavík deposits.
The Eocene regression and tillites in Iceland.
The most superficial knowledge of Icelandic geology suffices
to show that a Pliocene age of the Breiðavík deposits is a most
violent clash with the (unfounded) inference from the fact that
even the upper parts of the old plateau basalts abound unth