Palaeosecular Variation at the Society Islands, French Polynesia

The Society Islands are the peaks of volcanic cones which rise from oceanic depths in excess of 4 km and lie along a NW to SE lineament in the central Pacific basin. Oriented samples were collected from 53 sites on 5 of the younger islands of the chain. Geochronology indicates that all sites are younger than 3.4 My. Palaeomagnetic directions yield an angular standard deviation of 13.8° of the site VGP's about the geographic axis (which is indistinguishable from the mean VGP at the 95 per cent confidence level). This magnitude of palaeosecular variation is in accord with values predicted by secular variation models and suggests that the anomalous non-dipole field behaviour described at Hawaii has not extended to the region of French Polynesia.