Palaeomagnetic Investigation of an Old Red Sandstone Formation of Southern Norway

Abstract

PALAEOMAGNETIC measurements of Devonian rocks of Europe have posed an intricate problem, because the red sandstones from this period, which spread from Wales across Central Europe to Siberia, exhibit palaeomagnetic poles significantly different from that deduced from the Lower Devonian lavas in the Midland Valley of Scotland¹. Recent thermal demagnetization studies on some Old Red sandstones of the Anglo-Welsh cuvette², however, have revealed a weak component of high thermal stability with a direction of magnetization which is in good agreement with that found in these Lower Devonian lavas. Furthermore, application of the fold test has shown that the magnetism of this high temperature direction is PreHercynian. This result, together with the apparently high magnetic stability of the Scottish lavas, led Chamalaun and Creer² to suggest that the lavas give the best estimate of the direction of the Devonian field for Great Britain.