Self-reversal of chemical remanent magnetization during multiphase oxidation of synthetic titanomagnetites

Borok Geophysical Observatory, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Borok, Yaroslavl oblast, Russia

Abstract

[1]  The possibility of self-reversal of chemical remanent magnetization (CRM) is studied on synthetic samples of titanomagnetites (Fe_3-xTi_xO₄, where x = 0.2, 0.4, and 0.6) that experienced multiphase oxidation in air at 500^oC in the presence of the constant magnetic field H = 0.1 mT. The self-reversal was fixed in accordance with anomalous behavior of CRM curves of cooling (in H = 0) and heating (in H = 0). Complete self-reversal of CRM is discovered experimentally in samples of oxidized titanomagnetites with initial x = 0.6, while partial self-reversal is revealed in other titanomagnetite compositions. Superposition of a partial thermoremanent magnetization (pTRM) on CRM showed that heating curves of CRM+pTRM are also anomalous, but negative values of the total magnetization are not observed.

Received 19 July 2008; accepted 22 August 2008; published 12 September 2008.

Keywords: titanomagnetite, oxidation, magnetization, self-reversal.

Index Terms: 1500 Geomagnetism and Paleomagnetism; 1518 Geomagnetism and Paleomagnetism: Magnetic fabrics and anisotropy; 1519 Geomagnetism and Paleomagnetism: Magnetic mineralogy and petrology; 1533 Geomagnetism and Paleomagnetism: Remagnetization; 1540 Geomagnetism and Paleomagnetism: Rock and mineral magnetism; 3630 Mineralogy and Petrology: Experimental mineralogy and petrology.

Citation: Gapeev, A. K., and S. K. Gribov (2008), Self-reversal of chemical remanent magnetization during multiphase oxidation of synthetic titanomagnetites, Russ. J. Earth Sci., 10, ES6003, doi:10.2205/2008ES000305.