Hydrothermal alteration of magnetic fabrics of rocks in the Xiaoban gold-bearing shear belt, Fujian Province, China
Magnetic fabrics indicate that the Xiaoban shear zone underwent low-grade hydrothermal alteration in the Mesozoic (~180Ma). Samples studied come from altered and unaltered units from three mine levels. (1) Susceptibility is mainly due toparamagnetic minerals such as biotite and pyrite. The reduction...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2003 |
| País: | México |
| Institución: | Universidad Nacional Autónoma de México |
| Repositorio: | Redalyc-UNAM |
| OAI Identifier: | oai:redalyc.org:56842107 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=56842107 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra China anisotropy susceptibility Magnetic fabric hydrothermal alteration |
| Sumario: | Magnetic fabrics indicate that the Xiaoban shear zone underwent low-grade hydrothermal alteration in the Mesozoic (~180Ma). Samples studied come from altered and unaltered units from three mine levels. (1) Susceptibility is mainly due toparamagnetic minerals such as biotite and pyrite. The reduction of mean susceptibility is due to decrease in Fe content and changeof magnetic mineral size, as well as increase of diamagnetic minerals. (2) Anisotropy (P) decreases after hydrothermal alteration.Its tendency to change is the same as that of the mean susceptibility. (3) The AMS ellipsoid does not substantially change its shapeafter hydrothermal alteration. An oblate sphere is maintained. The minimum principal susceptibility axis (K3) falls close to theplane which is perpendicular to the schistosity for all samples. However, the maximum principal susceptibility axis is subject tolarge changes. The results indicate that new magnetic minerals are distributed on the existing schistosity plane, without a preferredorientation. |
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