The Ildeus mafic–ultramafic complex represents plutonic roots of a Triassic magmatic arc tectonically emplaced into the thickened uppermost crust beneath the Mesozoic Stanovoy collided margin. The mafic–ultramafic complex cumulates host Ni-Co-Cu-Pt-Ag-Au sulfide-native metal-alloy mineralization produced through magmatic differentiation of subduction-related primary mafic melt. This melt was sourced in the metal-rich sub-arc mantle wedge hybridized by reduced high-temperature H-S-Cl fluids and slab/sediment-derived siliceous melts carrying significant amounts of Pt, W, Au, Ag, Cu and Zn. Plutonic rocks experienced a pervasive later-stage metasomatic upgrade of the primary sulfide–native metal–alloy assemblage in the presence of oxidized hydrothermal fluid enriched in sulfate and chlorine. The new metasomatic assemblage formed in a shallow epithermal environment in the collided crust includes native gold, Ag-Au, Cu-Ag and Cu-Ag-Au alloys, heazlewoodite, digenite, chalcocite, cassiterite, galena, sphalerite, acanthite, composite Cu-Zn-Pb-Fe sulfides, Sb-As-Se sulfosalts and Pb-Ag tellurides. A two-stage model for magmatic–hydrothermal transport of some siderophile (W, Pt, Au) and chalcophile (Cu, Zn, Ag) metals in subduction–collision environments is proposed.
The Paleozoic volcano-sedimentary rocks within the structural basement of the horst-and-graben system of the Catalan Coastal Ranges (CCR) are composed of black shale, volcaniclastic sediments, lava flows, sills and lithocrystalloclastic tuffs. Paleozoic sediments are depleted in high-field strength elements (HFSE) such as Nb, Ta, Zr, Hf and Ti, suggesting their accumulation within the Andean-type active continental margin environment. Volcanic rocks within the Paleozoic CCR sequence belong to shoshonitic and high-K volcanic series and are enriched in Cs, Rb and Ba and depleted in HFSE, which is consistent with their derivation from metasomatized (possibly through deep recycling of pelagic sediments) subduction-related mantle source. The presence of sills (sill-sediment complex) suggests that Paleozoic basement of the CCR was formed within the rifted active continental margin or an arc-back-arc basin system akin to the modern Western Pacific subduction configuration. This complex volcanic terroir hosts world-class wines of the Priorat DOQ region. The presence of framboidal pyrite and magnetite, siderite, sphalerite xenotime, (La–Ce–Nd)-monazite, zircon and baddeleyite, as well as cuprite, tenorite and cupriferous and native silver in volcanic-derived black shale (and consequently in the world-famous “llicorella” soil overlying it) may have had dramatic effects on wine quality and sensory characteristics. These mineral features, together with strong enrichment of Priorat shale in Au, Ag and, to a lesser extent, Pt could have pronounced effects on (1) rates and specific types of chemical reactions; (2) plant metabolism; (3) response to nutrient components and (4) determination of grape flavor. Volcanic wine terroirs, such as the Priorat DOQ region, are special geologic environments for wine growth, capable of producing unique wine aromatic and gustatory characteristics.
Quaternary lavas (ankaramite, basalt, basaltic andesite, andesite, dacite) from the Kamchatka, Kurile, Ecuador and Cascade volcanic arcs contain Cl-bearing mineral microinclusions in rock-forming minerals and groundmass volcanic glass. They are represented by chlorargyrite (with a variable amount of native Ag), Cu, Ag, Sn, and Zn compounds with Cl and S, Sn- and Pb-Sb oxychlorides compositionally similar to abhurite and nadorite, as well as bismoclite and Cl-F-apatite. The Cl-bearing compounds with chalcophile metals are best approximated by mixtures of chlorargyrite with Cu sulfides, malachite, or azurite. Some Cl-bearing solid microinclusions in magmatic rock-forming minerals could have formed from Cl-rich melts exsolved from arc magmas during differentiation. Alternatively, specific magmatic microinclusions may record the decomposition of primary sulfides in the presence of Cl-bearing magmatic volatiles. Post-magmatic Cl microminerals found in fractures, pores, grain contacts, and groundmass glass are most probably precipitated from hydrothermal fluids accompanying their emplacement at the surface and post-eruption transformations in active fumarole fields. Assemblages of Cl-bearing microminerals with native metal, alloy, sulfide, oxide, and sulfate microinclusions in arc lavas potentially record late-magmatic to post-magmatic stages of formation of the epithermal and possibly porphyry mineralization beneath arc volcanoes.