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land the picture is yery similar. There is an anticline in
Fjördum and Eyjafjördur and a syncline in the Jökulsá á
Fjöllum area.
The boundaries between the TPB areas and the Quater-
nary rock series seem everywhere to be on the flanks of
anticlines. The dips are steeper there than nearer the axis
of the anticlines, very often 10—30°, so in many places they
form a flexure. Also near the boundaries the older rock se-
quences have higher dips than the younger ones, so these
structures have also been formed during a long time and not
only in Quaternary times.
The neovolcanic zone of Iceland, which has been active
since late Quaternary time, seems mainly to be confined to
synclinal structures. It is very doubtful if there is any “cen-
tral graben” existing at all in Iceland and the present gra-
bens such as the Thingvellir graben are rather small fea-
tures with downthrows of the order of 200—300 m.
The folding cannot be explained by sagging beneath thick
piles of younger volcanics as there are e.g. no young volca-
nics in the Breidafjördur-syncline.
The structural pattern of Iceland seems to indicate that
Iceland has suffered crustal compression and that no dilata-
tion or “drift” has taken place.
REFERENCES
Áskelsson, Jóhannes, 1960: Fossiliferous xenoliths in the móberg-forma-
tion of S-Iceland. Acta Nat. Isl. II, 3.
Cox, A., R. R. Doell and G. B. Dalrymple, 1964: Reversals of the earth’s
magnetic field. Science 144, 1537—1543.
Cox, A., D. M. Hopkins and G. B. Dalrymple, 1966: Geomagnetic polarity
epochs: Pribilof Islands, Alaska. Geol. Soc. Am. Bull. 77, 883—910.
Einarsson, Thorleifur, D. M. Hopkins and R. R. Doell, 1967: The strati-
graphy of Tjömes, N-Iceland, and its significance for the history of
the Bering Land Bridge. In: A symposium on the Bering Land Bridge
Stanford Univ. Press. 312—325.
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