Magnetic properties of basalt samples from Deep Sea Drilling Project holes 417D and 418A.

Abstract

This paper presents the results of magnetic studies on basalt samples recovered from Holes 417D and 418A on Deep Sea Drilling Project Legs 51, 52, and 53. These holes are located on 100-m.y.- old magnetic anomaly MO and penetrated, respectively, 365.5m and 548.0m into oceanic Layer 2. Studies of the Layer 2 basalts provide useful information on the thickness and the mean intensity of the magnetized layer responsible for the lineated magnetic anomalies. Because of good recovery in these holes, the present samples well represent the upper 500m of Layer 2 at the sites. The magnetic properties reported here are the intensity and inclination of natural remanent magnetization (NRM), the intensity of anhysteretic remanent magnetization (ARM), the median demagnetizing field (MDF) for NRM and ARM, the saturation magnetization, the saturation remanent magnetization, the initial susceptibility, and the thermomagnetic properties and lattice comstants of magnetic minerals contained in the basalt samples. In addition to the information carried by individual properties, relations between these parameters provide useful information concerning the mechanisms controlling the magnetic characteristics of the basement layers.-Authors