Characteristics of magnetite in submarine basaltic glass

Abstract

We have compared the rock‐magnetic characteristics of Cretaceous submarine basaltic glass (SBG) from DSDP/ODP Holes 417D, 418A, 807C and 543A to data from Holocene glasses from the East Pacific Rise. Both groups are very similar in that they contain single‐domain, low‐Ti magnetite as the carrier of a strong and stable remanent magnetization. the behaviour of magnetic hysteresis in SBG is, however, dominated by superparamagnetic grain‐size populations. Transmission electron microscopy revealed spherically shaped grains of 10‐20 nm diameter with crystal lattice properties consistent with magnetite. These grains could be responsible for the magnetic behaviour of SBG. Copyright © 1994, Wiley Blackwell. All rights reserved