The Iberian Pyrite Belt (IPB) is recognized as having one of the major concentrations of volcanogenic massive sulfide (VMS) deposits on Earth. Original resources of about 2000 Mt of massive sulfides have been reported in the province. Recent classifications have considered the IPB deposits as the bimodal siliciclastic subtype, although major differences can be recognized among them. The main ones concern the hosting rocks. To the north, volcanic and volcaniclastic depositional environments predominate, whereas to the south, black shale-hosted VMS prevail. The mineral composition is quite simple, with pyrite as the main mineral phase, and sphalerite, galena, and chalcopyrite as major components. A suite of minor minerals is also present, including arsenopyrite, tetrahedrite-tennantite, cobaltite, Sb-As-Bi sulfosalts, gold, and electrum. Common oxidized phases include magnetite, hematite, cassiterite, and barite. The spatial relationship between all these minerals provides a very rich textural framework. A careful textural analysis reported here leads to a general model for the genetic evolution of the IPB massive sulfides, including four main stages: (1) Sedimentary/diagenetic replacement process on hosting rocks; (2) sulfides recrystallization at rising temperature; (3) metal distillation and sulfides maturation related to late Sb-bearing hydrothermal fluids; and (4) metal remobilization associated with the Variscan tectonism. The proposed model can provide new tools for mineral exploration as well as for mining and metallurgy.Minerals 2019, 9, 653 2 of 20 structural and tectonic settings; genetic models; the origin of mineralizing fluids; and economic aspects related to resources, reserves, tonnages, and ore grades.In spite of the enormous amount of published research, the generation of massive sulfide deposits in the IPB remains controversial. At least a part of this issue is due to a generalized tendency to assimilate the ore genesis in the IPB to classic genetic models for VMS deposits which are based on present comparables (i.e., black smokers, brine pool). A general review of published proposals for the generation of VMS in the IPB is detailed below. Geodynamic interpretations suggest that during the Late Devonian-Mississippian the IPB was affected by a period of regional extension with the breakdown and compartmentation of Late Devonian homogeneous basin and the beginning of the volcanic activity [26,27]. This paleogeographic environment favored the generation of hydrothermal systems, and the formation of the massive sulfide deposits [10]. According to Barriga [28] and Barriga and Fyfe [29], mineralizing fluids derived from seawater were equilibrated with underlying volcanic, volcanoclastic, and sedimentary rocks. These fluids were expelled on the seafloor where massive sulfide formed below a sealing chert layer that promoted ore precipitation but inhibited oxidation and dispersion. Based on Pb isotope analyses, Marcoux et al. [30] showed a homogenized metal source. Sáez et al. [11,23,31] and Almodóvar et...
