Rock Magnetism and Polar Wandering

Abstract

IT is now generally accepted that lava flows become permanently magnetized in the direction of the local geomagnetic field when they cool down through their Curie point1. Similarly, most sediments, on deposition, acquire a weak magnetic polarization2. This magnetization is thought to be due to lining-up of the minute permanently magnetized particles of the ferromagnetic minerals as they sink to the bottom. If used with caution, studies of rock magnetism may therefore yield valuable data concerning the direction of the geomagnetic field in the past.