A palaeomagnetic and rockmagnetic study of sediment cores from the Zaire submarine fan

Abstract

The characteristic directions of the Natural Remanent Magnetization (NRM) and some rockmagnetic parameters have been determined as a function of stratigraphic position in 10 cores from the Zaire submarine fan.

Most of the sediments have a weak and partly unstable NRM. The top 50 to 150 cm of many cores show a higher NRM intensity. The prevailing low NRM intensities are likely to be a consequence of pyritisation of a major part of the magnetic mineral fraction. Low negative values for the mean characteristic inclination are in accordance with near equatorial sediments of not more than a few hundred thousand years. A correlation of relatively high mean values for the remanent hysteresis parameters H'cr and IRM>200 with cold climatic periods suggests that the magnetic relict which has escaped pyritisation may still reflect original variations in magnetomineralogy.