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Viðbót í prófórk:
Auk ofangreindra heimilda um mælingar P. Löwen-
öms við Island, er þeim lýst stuttlega í Gilberts, Ann.
der Physik, 29, 438-441, 1808.
SUMMARY
MAGNETIC DECLINATION MEASUREMENTS IN
AND AROUND ICELAND
This paper describes various properties of the
present geomagnetic field, including the magnetic
declination which has been used for navigation
purposes for many centuries. Measurements of the
declination were made by various expeditions to Ice-
land since about A.D. 1750 or possibly earlier, but
documentation on their results is scattered, and little
is known of the methods used or their accuracy. Such
measurements turn out to be much more useful when
made at sea than on shore in Iceland, because of the
large disturbing effects of magnetic remanence in local
basalt rock formations.
A list of declination measurements, based on
original compilations by Th. Sigurgeirsson and Th.
Sæmundsson, is provided in the paper. The most
valuable series of observations in the Iceland area
include those of P. Löwenörn in the 1780’s, as well
as French measurements from the period 1830-1900.
The only aeromagnetic survey of Iceland for which
declination values are available, is that of G.W. Haines
et al. in 1965.
It is found that the westerly declination may
have reached a maximum early in the 19th century.
This is also in agreement with global geomagnetic
reconstructions based on historical íield measurements
and archeomagnetism, and may be of use in dating
lavas or artifacts in Iceland. The magnetic inclination
appears to have been fairly constant at 75-77 .
58 JÖKULL,No. 43, 1993