Magnetization of the oceanic crust

摘要

TheVine‐Matthews1963 model of the magnetic structure of the igneous oceanic crust, in which basement is considered to be made up of alternating normal and reverse magnetic polarity blocks with a one‐to‐one match with linear marine magnetic anomalies, has received wide acceptance in the geological and geophysical community. Comparison of the results from studies of samples obtained by dredging, submersible, and shallow drilling, with magnetic anomaly inversion and modeling are generally consistent with this model if the sections of magnetic crust are considered relatively thin—of the order of a kilometer in vertical thickness. However, work that has taken place in the last four years seems to indicate that the magnetic structure of the oceanic crust is a great deal more complicated than originally envisaged. Recent studies of the oceanic basement basalt recovered by the GLOMAR CHALLENGER, particularly from deep basement holes in the Atlantic, have indicated that the net magnetization of the upper 600 meters of igneous crust may, in some places, appear to be insufficient to contribute much to the overlying anomaly amp