EXAMPLE OF MAGNETIC-PROPERTIES AS INDICATORS OF ALTERATION IN ANCIENT OCEANIC LITHOSPHERE - OTHRIS OPHIOLITE

Detailed paleomagnetic and rock magnetic studies of samples from five distinct rock units of the ophiolite complex from the Othris Mountains, central Greece, were combined with limited petrologic investigations in an attempt to obtain valuable information regarding the alteration processes affecting ancient oceanic crusts. The diversity and character of the magnetic properties within several lithologies of the Othris ophiolite testify to the localized and distinctive character of each alteration event, and suggest that Othris did not undergo a pervasive regional alteration similar to that hypothesized for the Smartville, California ophiolite. The inherent value of the laboratory viscous remanent magnetization (VRM) studies, both acquisition and response to alternating field (AF) demagnetization, is especially apparent as these studies enabled the recognition of a hard stable VRM component in the natural remanent magnetization. © 1979.