Paleomagnetism of the Geulhemmerberg KIT boundary section, the Netherlands

Abstract

Paleomagnetic samples of six clay layers from an interval containing the Cretaceous/Tertiary (K/T) boundary in the Geulhemmerberg cave show only normal polarities, contrary to the expected reversed directions. The unique preservation of the sediment makes it unlikely that the normal polarities are an overprint through weathering or that the acquisition of the remanence has been delayed by post-depositional diagenetic formation of magnetite. Possibly, the normal polarities are the result of a relatively short relaxation time of the magnetic minerals which would cause the magnetic domains to realign with the present-day field, a process which would occur without affecting the preservation.