Rit (Vísindafélag Íslendinga) - 01.07.1962, Page 4

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for the laboratory measurements. My first concern was to
fill out gaps in the map of the Hvalfjörður-Borgarfjörður
area, with special attention to the possibility of gaps in the
record. Then the mapping was extended from Borgarfjörður
to the Steingrímsfjörður area, i.e. down to the best known
horizons of Lower Tertiary (Eocene) lignite. Thus a section
from Upper Pleistocene down to the Eocene had been ob-
tained, containing about 25 magnetic groups.
In many cases I had the impression that each magnetic
period could hardly he longer than a few hundred thousand
years with the implication that our record might comprise
no more than %, to Vo of the complete post-Eocene succes-
sion of geomagnetic periods. This prompted many questions.
Were Nx and Rj really of Pleistocene age, could there not
be still younger magnetic groups? How large was the gap
between Rx and N2? Were not the Plateau groups down to
R3, which had been subjected to peneplanation and successive
valley erosion, of rather high Tertiary age in spite of the
fact that they contain vestiges of frost action and even signs
of some glaciations? The only way to deal with these ques-
tions was to make a detailed stratigraphic study of the Upper
Tertiary to Pleistocene rocks of a much larger area.
Considerable work was done in Eastern and Middle South-
ern Iceland but the main emphasis was laid on the area from
Tjörnes across northem Central Iceland to the southwestern
part of the country. Parts of this area (Ingólfsfjall, Hreppar)
were studied in common with Th. Sigurgeirsson.
As a first step a survey of the area Tjörnes—Bárðardalur
was worked out (Einarsson 1958 a). This important area is
of very complicated structure and as a result it was not found
possible to correlate with certainty the important Upper
Plateau Basalts west of Bárðardalur with the Tjömes sedi-
ments.
One approach I used in that study was morphologic ana-
lysis. This led to further morphologic studies in Middle
Northern Iceland as a possible means of distinguishing various