Palaeomagnetic Evidence for the Ordovician Geomagnetic Pole Position

Abstract

I HAVE obtained evidence which supports a pole position in the region of 165° E., 13° N. (antipole 15° W., 13° S.) on the present latitude–longitude grid and relative to the British Isles. This agrees with the palaeoclimatological evidence reported by Spjeldnaes¹, whose studies, based chiefly on the global distribution of shallow water shell deposits, led him to suggest that the Ordovician climatic zones could be deduced from the faunal provinces and that polar ice caps existed during this period. Spjeldnaes¹ infers a rotational pole lying in or west of Africa which would correspond to the palaeomagnetic pole at 15° W., 13° S. These data are not in conflict with Wegener's hypothesis of continental drift, for the positions of the climatic zones on either side of the Atlantic are improved by moving the continental blocks together¹. There is little corresponding information for the 165° E., 13° N. pole because the data available for China are too few to say whether the palaeolatitude and palaeomagnetic latitude are in agreement. Spjeldnaes concluded from a consideration of Runcorn's² palaeomagnetic polar wandering curves that a magnetic pole at about 165° E., not far from the Equator, in the region of 0°–25° north of it, would correlate well with the available data.