Role of rheological heterogeneities in vein-ore localization
| Autor: | M. Moisy, Y. Gros, C. Castaing, J. C. Chabod, D. Cassard |
|---|---|
| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Canadian Journal of Earth Sciences. 30:113-123 |
| ISSN: | 1480-3313 0008-4077 |
| DOI: | 10.1139/e93-011 |
| Popis: | Structural studies of the Saint-Salvy zinc deposit and other Hercynian, veinhosted ore deposits in the French Massif Central and Pyrénées reveal a fourstage evolution of mineralized structures under rheological control: (i) localization of potential mineralized areas, guided by the presence of first-order lithological or structural heterogeneities that caused stress and strain perturbations; (ii) creation of second-order heterogeneities, corresponding to indurated shear zones that acted as rheological discontinuities; (iii) tectonic activation of these second-order heterogeneities, opening voids that allowed circulation of hydrothermal fluids and periodic trapping of ore minerals; (iv) reworking and partial destruction of the mineralized structures, caused by the reactivation of anisotropic surfaces acting as zones of weakness. The interaction between preexisting, first-order heterogeneities and regional shear strain caused instability, which in turn produced second-order and then lower-order heterogeneities. Such progressively smaller heterogeneities induced an increasingly focused, centripetal localization of structural disturbances that enabled hydrothermal fluid channelling. This is the reason that lower-order and late structures preferentially bear economic mineralization. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|