Mineral association and significance of the Pb-Cu-Zn +- Ni-Co-Sb late-hercynian vein deposits from the sierra de la demanda, Spain

摘要

Several Pb-Zn-Cu+-Ni-Co-Sb vein deposits occur in Cambrian sedimentary rocks in the southeastern portion from the Sierra de la Demanda (La Rioja, Spain). The Najerilla district is constituted by the Najerilla, Corrales and Riguelo mines, which mainly contain galena with subordinate Ni-Co sulphide and Cu-Pb-Ag-Sb sulphosalts, and with quartz and Fe-rich carbonates as principal gangue. They share a number of common characteristics, including: (1) strong structural control; (2) same wall rock (alternating quartzites and shales) and similar hydrothermal alteration; (3) equivalent mineral assemblages comprising minor concentrations of Ni-Co-g-Sb-bearing minerals; (4) deposition at low temperature and pressure. The available information suggests that the underlying sedimentary sequence is the potential source for mineralizing fluids and metals.