History of Geophysical Research in The Netherlands ... - DWC - KNAW

1. Other studies. The palaeomagnetic research in the Mediterranean region
gave rise to some special doctor 's theses. A. A. Dijksman investigated changes
in the geomagnetic polarity in a column of Miocene sediments in Spain (1977) .
He was able to describe the behaviour of the geomagnetic field during some reversals
. The investigation of sediments in Southern France by C. van den Ende
(1977) gave information on the secular variation of the earth's magnetic field
during the Permian. He also studied the magnetic susceptibility of rocks in order
to find a possible relation between the anisotropy of susceptibility and natural
remanent magnetization. FinaIly, the thesis written by P. H. M. Dankers
(1978) must be mentioned; it deals with the relation between the magnetic properties
and the grain size of magnetic minerals and the influence of temperature
on this relationship .
1.9.2. Palaeomagnetism at the Municipal University of Amsterdam
Under the leadership of J. Hospers , professor in Amsterdam from 1965 to
1975, various palaeomagnetic studies were initiated at the Municipal University.
J. Hospers and S.l. van Andel (1967 and 1968) tried to calculate from palaeomagnetic
data the value of the earth's radius in several geological periods. These
data showed that a constant radius could be supposed as weIl as a slow expansion
of the earth or a small contraction . At any rate the break-up of the Pangaea
continents cannot be explained by an expanding earth. This research led to
the thesis of Van Andel (1968). H.M. van Montfrans (1971), who was also at the
Municipal University of Amsterdam, investigated Quaternary sediments from
the North Sea basin to look for a correlation bet ween the stratigraphic levels
and the time scale of the reversals in the earth 's field. It turned out to be
possible to date a number of levels by means of reversals of geomagnetic polarity.
The palaeomagnetic research of Hospers and his co-workers at Amsterdam
ended when in 1975 geophysics in the Netherlands was concentrated at the
State University of Utrecht.
It is expected that the magnetic properties of rocks and especially the study
of palaeomagnetism under the leadership of Zijderveld , who was appointed professor
at Utrecht in 1981, will yield important information about the processes
and movements in the crust of the earth.
REFERENCES TO CHAPTER I
Andel, S.1. van (1968) - A test of earth expansion hypotheses by means of
paleomagnetic data. Proefschrift, Amsterdam.
Anonymous (1967) - NAVADO 111. Bathymetric, magnetic and gravity investigations,
1964-1965. Hydrographic Newsletter, Spec. Publ. Nr. 3, parts 1,
2 and 3, 1967.
As, J.A. and J.D.A . Zijderveld (1958) - Magnetic cleaning in paleomagnetic
research . Geophys. Journ. Roy. Astr. Soc., 1,308-319.
As, J. A. (1960) - Instruments and measuring methods in paleomagnetic research.
Meded. en Verh. K.N.M.I., Nr. 78.
As, J.A. (1967a) - Past, present and future changes in the earth's magnetic
field. Magnetism and the Cosmos , 29-44, 1967, Oliver and Boyd, Edinburgh.
As, J.A. (1967b) - Measurement of the anisotropy of the susceptibility. In:
Methods in Paleomagnetic Research, 362-367, Elsevier, Amsterdam.
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