(Table 1) Anisotropy of magnetic susceptibility of basalts at DSDP Hole 89-462A

Measurements of the anisotropy of magnetic susceptibility (AMS) in basalts cored from 1070 to 1209 m sub-bottom depth in Hole 462A reveal that samples with a high ratio of maximum (K1) to minimum (K3) principal susceptibility show a prolate type of anisotropy in which K1 axes are nearly vertical. For other prolate types, K1 axes vary widely. Although the oblate type of AMS is less common among these basalts, K3 axes are nearly vertical in the upper units and horizontal in the lower units. The anisotropy of compressional wave velocities measured for the same specimen shows no correlation with the degree and type of AMS. This finding indicates that AMS could have been caused by variations in flows but not by compressive stress. Processes of emplacement of basaltic sills and flows must have been complex, because directions of principal axes of AMS vary from unit to unit.