Rit (Vísindafélag Íslendinga) - 01.07.1962, Side 179

SUMMARY AND GENERAL CONSIDERATIONS.
1. Stratigrapliy antl Paleomagnetism.
Towards the top of the Tertiary Basalt Plateau in Iceland
a group of basalts can be discerned which in several respects
contrasts with the main, 5—6 km thick pile. It is e.g. typi-
cal for the latter that the sediments contained are nearly
exclusively fine-grained and may be considered as character-
izing a dry lava desert. The rocks are very often infilled with
zeolites, chalcedone or calcite and the basalts may be some-
what altered. Where the upper and lower basalts meet at a
discordance these differences often distinguish them clearly.
But the freshness and lack of infillings is no certain charac-
teristic of the younger rocks for it is a rule that the older
rocks are quite fresh at high elevations and here the zeolites
tend to be absent. This has sometimes led to misinterpreta-
tion.
The topmost group of the Plateau can be distinguished in
other ways. Sometimes it rests unconformably on the lower
basalts and often it shows slighter dip than these. Further,
it contains coarser fluviatile and eolian sediments and clear
signs of frost action. Cryoturhation has in some cases trans-
formed the gravels in such a way that they very much re-
semble moraines. In other cases a clearly striated floor makes
the assumption of a local glacier likely. But striated stones
are very scarse in these conglomerates and in the directions
of the striae on the floor, there does not appear to be any
such regularity as a regional glaciation would lead one to
expect.
This group is here called Young Plateau Basalts. This name
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