A Sensitive Astatic Magnetometer and Some Measurements of the Palaeomagnetism of Some Cretaceous Sediments

Abstract

An astatic magnetometer has been constructed with a maximum sensitivity of 10⁻⁸ oersted. The instrument is primarily designed for measurements of rock magnetism and is suited for measurement of magnetization intensities of more than 5 x 10⁻⁷ gauss. It may also be used for measurements of susceptibilities down to 10⁻⁷ gauss/oersted. Test measurements have been made to prove its performance. Some Upper Cretaceous sandstones have been collected as a preliminary to palaeomagnetic research in New Zealand. Their magnetization proved too low for measurement.