Stable isotope composition of F-Pb-Zn mineralization in the Valle de Tena (Spanish Central Pyrenees)

This study, dealing with the stable isotope (C, O, and S) geochemistry of F-Pb-Zn deposits, is part of an integrated metallogenetic study of the Valle de Tena (Central Pyrenees). The objective of this work is to place constraints on the origin of the mineralizing solutions and sources of sulphur and metals. Two types of mineralization have been identified: (1) stratabound ores linked to an emersion episode that occurred during the Namurian to Westfalian transition (Portalet mines), and (2) low-temperature hydrothermal veins related to post-Hercynian extensional tectonics (Yenefrito and Lanuza mines, and Tebarray occurrences). Stable isotopic study indicates that the source of mineralizing components was the local Upper Palaeozoic country rocks in the case of the stratabound Portalet deposit (biogenic sulphides and connate waters, modified by some meteoric input through a karst surface). In the case of vein deposits, stable isotopes point toward either modified connate water or marine water as the mineralizing fluid, with sulphur and metals derived from a mixture, in different proportions, of regional igneous and (meta)sedimentary country rocks. Received: 6 November 1995 / Accepted: 6 September 1996