Jan Hosper's Key Contributions to Geomagnetism



Although Bernard Brunhes in 1904 presented the first evidence that the geomagnetic field had once reversed in polarity [Laj et al., 2002], modern studies of reversals only began in the late 1940s with the work of Jan Hospers and Alexandre Roche [Opdyke and Channel, 1996]. Hospers also initiated modern studies of the time-averaged form of the geomagnetic field [Frankel, 1987]. His empirically based notion—that over several thousand years the geomagnetic field averaged to a geocentric axial dipole (GAD) that, as he and others showed, had recurrently reversed its polarity—allowed Creer et al. [1954] to trace the movement of the geographic pole (apparent polar wander path) relative to Britain and by geological extension, to Europe as well. This was the first such path based on paleomagnetic evidence, and it led in turn to the first successful physical test of continental drift [Irving, 1988].