Encyclopedia of Geomagnetism and Paleomagnetism

2007 Edition
| Editors: David Gubbins, Emilio Herrero-Bervera

Magnetic Susceptibility, Anisotropy, Effects Of Heating

  • Jaime Urrutia‐Fucugauchi
Reference work entry
DOI: https://doi.org/10.1007/978-1-4020-4423-6_186
Study of the anisotropic properties of magnetic susceptibility and remanent magnetizations is an active field of research in paleomagnetism. These studies have important applications in petrofabrics, structural geology, metamorphism, rock magnetism, volcanology, and tectonics. Here we concentrate on the anisotropy of magnetic susceptibility (AMS) of rocks measured at low magnetic fields, and in particular, on the effects of laboratory heating on the AMS of rocks. Mineralogical changes resulting from heating samples in the laboratory have long been recognized and studied (see Table M6). The potential use of temperature‐induced effects to investigate composite magnetic fabrics needs further development.
Table 6

Laboratory data on heating‐induced thermochemical reactions

From

To

°C

 

Igneous

     

Impure titanomagnetites

Magnetite

>300

 

Magnetite

Maghemite

150–250

 

Olivines

Magnetite

>300

 

Pyrite

Magnetite

350–500

 

Maghemite

Hematite

350–450

 

Magnetite

Hematite

>500

 

Pyroxenes

Magnetite...

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Notes

Acknowledgments

Partial support for the magnetic fabric studies has been provided by DGAPA projects IN‐116201. Thanks are due to Editor E. Herrero‐Bervera for the invitation to contribute, encouragement, and useful comments.

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  • Jaime Urrutia‐Fucugauchi

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