Fróðskaparrit - 01.01.1968, Side 78

86
A Note on some Geo-Electrical Measurements
Combined with experiences from other electricai resistivity
measurements on the Faroe Islands and in parts of Den-
mark thi/s information forms the baekground of the geølogical
interpretation as mentioned in Fig. 5 B.
Stratigraphically the basalt belongs to the lower part of
the middle series of basalt (Noe-Nygaard, 1962). The resisti-
vity of the basalt of about 3,000-6,500 oihm-m is remarkably
high. Thus very deep electrical soundings in Saxundalur
(Streymoy) and at Sørvágsvatn (Vágar) indicate values in the
interval from 500 to about 1500 ohm-m for the middle basalt
series and values less than 100 ohm-im for the lower basalt
series.
Fig. 6 gives a completed presentation of the geological inter-
pretation of the geophysical data. It shows that generally the
thickness of the sedimentary cover increases towards the cen-
tral parts of the cultivated area. The maximum thickness is
about 7 m (Sounding No. 4). The average thickness is calculated
to about 4 m. The profile through soundings Nos. 1-7 shows
that tthe surface of the basalt probably must have a moderate
relief. Everywhere the surface of the basalt is above present
sea-level.
Acknowledgement
The electrical measurements at Tjørnuvík were carried out
at the suggestion of afdelingsgeolog, mag. scient. Jóannes Ras-
mussen, Tórshavn, and the author wishes to thank him for
co-operation in connection with planning of the measurements.
The facilities offered by Aarhus University Computing
Center are greatly appreciated.
This survey has been financially supported by Árhus Uni-
versitets Forskningsfond and Academica Faroensis.