Fróðskaparrit - 01.01.1977, Síða 87

A marine geophysical project
Magnetic measurements
By P. Hedebol Nielsen
This is a preliminary note on a marine geophysical project
the aim of which is to obtain some geophysical information
about the economic zone of the Faeroe Islands. The project is
organized by Jóannes Rasmussen (Geological Survey of Den-
mark and Føroya Jarðfrøðisavn), but ships have been made
available by the Faeroese government and the collection and
processing of the data is conducted by the author in collabora-
tion with the laboratory of geophysics at Geological Institute,
University of Aarhus. Only magnetic measurements have been
made until now but to decrease the ambiguity of the interpre-
tation other methods will, hopefully, be included later.
In the summer 1976 marine magnetic measurements were
carried out on board M/V Dagstjørnan and the approximate
positions of the lines are shown on fig. 1. The total length of
the lines is about 7000 km and along these lines the following
measurements were made: the water depth was measured by
echo sounding, the position was found from Decca and Loran-
C observations and the total magnetic field was measured by
a marine proton magnetometer (kindly lent by the Geological
Survey of Greenland).
Most of the lines are along green Decca lines (North Scottish
chain) and fixes were made when crossing a red line or with
time intervals of 5—15 minutes. The difference between Loran-
C and Decca fixes (and the absolute error (?), may reach nearly