Palaeomagnetic results from Mounts Gambier and Schank, South Australia

Abstract

Abstract Palaeomagnetic results are presented for two young volcanoes in southeastern Australia. Directions for the basalt and lava spatter, erupted near the beginning and end of activity at Mt Gambier respectively, are identical and suggest there was no long break in activity. The direction for basalt at Mt Schank differs from that of Mt Gambier by several degrees, and indicates that the two volcanoes differ in age, probably by three centuries or more. Directions for both volcanoes are much shallower than the present‐day geomagnetic direction at the locality. Palaeomagnetic field strength estimates, from baked ash at Mt Gambier and baked sand at Mt Schank, are higher than the present‐day field strength. Comparisons with other late Pleistocene and Holocene results suggest that ages for Mts Gambier and Schank are either greater than 7000 years or between 5000 and 1000 years. These conclusions are consistent with published radiocarbon ages from charcoal in fossil soil horizons sealed beneath ash deposits.