The aeromagnetic anomalies and the bathymetry of the central part of the Hawaiian Ridge

Abstract

An interpretation is given of a total force aeromagnetic survey of an oceanic area limited by lat. 22° N and lat. 25° N and by long. 162° Wand long. 167° 30′ W. The bathymetry is described and is used to infer the geological history. Magnetic anomalies trend east over the Hawaiian Ridge and trend north-east over the surrounding sea floor. The larger anomalies are caused by normal, or more rarely by reverse, magnetisation of the bathymetric features, the smaller anomalies by magnetically anomalous bodies in the earth's crust. Anomalous bodies in the Hawaiian Ridge are probably serpentinised ultrabasic rocks that lie beneath the volcanic vents, and those away from the Hawaiian Ridge are probably north-east trending intrusions.