The Stokes Magnetic Anomaly

Abstract

SummaryThe Stokes Anomaly is traced for over 3000 km, from 700 km S of New Caldedonia almost to the eastern edge of the Campbell Plateau. For most of its length the anomaly is a double feature with positive peaks from 30 km to 50 km apart. From outcrops on the western side of the Southland Syncline it is inferred that the northeastern peak is caused by Permian volcanics, and the south-western peak by the associated Permian intrusives. The anomaly is displaced dextrally by a total of 1000 km where it crosses the New Zealand land mass. About 500 km of the displacement is caused by displacement on the Alpine Fault Zone, and the remainder by distributed dextral shear and by displacement on other sub-parallel faults.