Rit (Vísindafélag Íslendinga) - 01.06.1967, Side 30

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The second tectonic phase is the one mentioned earlier, in
which faulting created the present outlines of the country
and in which the main gravity anomaly was formed. The
movement was vertical but there was hardly any tilting.
The age of this phase is a few million years. Following the
tectonic phase, erosion began to mould the present valleys
and fjords. At the same time the land kept on rising in steps,
in all about 300 m, probably in isostatic response to unload-
ing (Trausti Einarsson 1962 og 1963 a).
The faultlines of this tectonic phase have the dominant
directions SW—NE and the complementary SE—NW, Fig. 12,
and thus show close relationship to the Reykjanes Ridge.
There is then most probably a genetic relationship between
this tectonic phase in Iceland and a major event in the his-
tory of the Mid-Atlantic Ridge.
It is possible that in the first and second tectonic phases
there was widespread subsidence in the Scandic area, but
the evidence is most uncertain.
Conclusions.
1. Up to the end of the Jurassic, or even longer, Greenland
seems to have been situated near northwestem Europe
and then to have drifted some 1200 km westwards. The
drift itself cannot be traced by available geologic data.
2. Some 100 million years separate the Jurassic and the
oldest, about 20 million years old rocks of Iceland, and
these seem not to reflect a continuation of drift. It is un-
certain whether a Mid-Atlantic Ridge existed or influenc-
ed the outpouring of the older basalts. But intensive dyke
Fig. 12. Some mcán faults formed during the second 'tectorúc phase,
in which the present country was cut off from the earlier peneplained
land. Vertical hatching: later additions, mainly volcanic. Circles:
boundaries of original drainage area in NW- and SE-Iceland.