Low-field susceptibility anisotropy of some biotite crystals
| Autor: | Karel Zapletal |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Analytical chemistry Astronomy and Astrophysics engineering.material Magnetic susceptibility Paramagnetism Geophysics Nuclear magnetic resonance Ferromagnetism Space and Planetary Science Remanence Mössbauer spectroscopy engineering Curie temperature Anisotropy Biotite |
| Zdroj: | Physics of the Earth and Planetary Interiors. 63:85-97 |
| ISSN: | 0031-9201 |
| DOI: | 10.1016/0031-9201(90)90063-4 |
| Popis: | The low-field magnetic susceptibility anisotropy (LMA) of weakly magnetic rocks is dominated by paramagnetic minerals among which micas, and mainly biotite, is important. For this reason, the LMA of biotite crystals was investigated in detail. Natural biotite crystals (from ten localities) having a wide range of iron concentration were also studied by other methods, including optical microscopy, X-ray microanalysis, Mossbauer spectroscopy and induced isothermal remanent magnetization. Ferromagnetic inclusions disturbing the magnetic properties of biotite were revealed in some crystals. The measured mean bulk susceptibility of pure crystals (four localities) ranges from 1.0 × 10 −3 to 1.8 × 10 −3 SI and agrees with the susceptibility calculated from the iron concentration (ranging from 12 to 20 wt.%) determined for each specimen. The susceptibility ellipsoid of pure biotite crystals is rotational about the minimum susceptibility direction parallel to the crystallographic c ′-axis, and the anisotropy degree ranges from 1.34 to 1.36. |
| Databáze: | OpenAIRE |
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