Paleomagnetism

The study of paleomagnetism started in the 1940s when the British physicist Patrick M. S. Blackett invented a device for measuring the very small amount of magnetic fields associated with magnetic minerals. The astatic magnetometer consisted of a number of tiny magnets suspended on a thin fiber. The magnetometer was rotated around a sample and the amount of magnetism measured by changes in the fiber.

Today, two other devices are more commonly used to study paleomagnetic materials: the spinner magnetometer and the cryogenic magnetometer. Each of these devices represents a significant improvement in the ability of a researcher to detect and measure the magnetic field associated with a mineral.