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AGU: Journal of Geophysical Research, Solid Earth

 

Keywords

  • magnetic minerals
  • magnetite
  • magneto-optical imaging

Index Terms

  • Geomagnetism and Paleomagnetism: Magnetic mineralogy and petrology
  • Geomagnetism and Paleomagnetism: Rock and mineral magnetism
  • Mineralogy and Petrology: Petrography, microstructures, and textures
  • Physical Properties of Rocks: Magnetic and electrical properties
  • Physical Properties of Rocks: Instruments and techniques
Abstract
Cited By (2)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, B04105, 10 PP., 2007
doi:10.1029/2006JB004305

Magnetic field visualization of magnetic minerals and grain boundary regions using magneto-optical imaging

Alexander V. Bobyl

A. F. Ioffe Physico-Technical Institute, St. Petersburg, Russia

Yuri Y. Podladchikov

Physics of Geological Processes, University of Oslo, Oslo, Norway

Håkon Austrheim

Physics of Geological Processes, University of Oslo, Oslo, Norway

Bjørn Jamtveit

Physics of Geological Processes, University of Oslo, Oslo, Norway

Tom H. Johansen

Department of Physics, University of Oslo, Oslo, Norway

Daniel V. Shantsev

Department of Physics, University of Oslo, Oslo, Norway

Magneto-optical imaging based on the Faraday effect has been used to characterize magnetic minerals embedded in a nonmagnetic matrix. We have studied magnetite grains and magnetite-magnetite grain boundary regions in samples of skarns and serpentinites. Distributions of the remanent magnetic field were measured across at the surface of polished thin sections kept at room temperature. The magneto-optical images resolve directly magnetic structures on length scales ranging from millimeter down to micrometer, thereby revealing the shape and arrangement of the magnetite grains and allow determination of the grain magnetization. We find that (1) for the skarns the intergrain interactions do not affect the magnetic properties of magnetite grains within 0.6–60 μm of each other, while the saturation remanence decreases weakly with increasing grain size from 40 μm to 0.6 mm, and (2) for the serpentinites the magnetic properties of the stripes are size-dependent due to variations in chemical composition.

Received 21 January 2006; accepted 21 November 2006; published 11 April 2007.

Citation: Bobyl, A. V., Y. Y. Podladchikov, H. Austrheim, B. Jamtveit, T. H. Johansen, and D. V. Shantsev (2007), Magnetic field visualization of magnetic minerals and grain boundary regions using magneto-optical imaging, J. Geophys. Res., 112, B04105, doi:10.1029/2006JB004305.

Cited By

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