The Intensity of the Tertiary Geomagnetic Field

Summary Although many paleomagnetic directional data are now available, very little is known of the ancient intensity of the Earth's magnetic field. This paper describes the determination of the Tertiary geomagnetic field intensity using baked contacts (red sandstones, conglomerates and dykes) and dykes from Scotland and lavas and baked laterites from Iceland. The field intensity results obtained correspond to a mean Tertiary dipole moment of 4.94 × 1025 gauss. cm3 in Scotland and a mean Tertiary dipole moment of 5.34 × 1025 gauss. cm3 in Iceland. These values contrast with the present geomagnetic dipole moment which is 8.0 × 1025 gauss. cm3.