The Palaeomagnetism of the Stormberg Lavas of South Africa I: Evidence for a Genuine Reversal of the Earth's Field in Triassic-Jurassic Times

Abstract

The lowermost lavas of the Stormberg basalts are reversely magnetized and the uppermost lavas normally magnetized with a transition zone in between where the declination and inclination change progressively. Several different self-reversal mechanisms are reviewed in the light of a variety of field and experimental evidence, all of which support the hypothesis of a genuine reversal of the main geomagnetic field during Triassic-Jurassic times when the lavas were extruded.