Native Metals and Alloys in Trachytes and Shoshonite from the Continental United States and High-K Dacite from the Bolivian Andes: Magmatic Origins of Ore Metals in Convergent and Within-Plate Tectonic Settings

Kepezhinskas, Pavel; Бердников, Н. В.; Konovalova, N. S.; Kepezhinskas, Nikita; Krutikova, V. O.; Kirichenko, E.

doi:10.1134/s1819714022050025

Cited by 9 publications

(12 citation statements)

References 76 publications

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“…Paleozoic lavas, sills and pyroclastics from the Priorat DOQ region display low (typically < 2) Nb/Th ratios characteristic of subduction-related magmas [47,59,61,65,80,81]. On the other hand, low Zr/Nb ratios (< 10) in some volcanic samples from the Priorat region are comparable with OIB-like values [41,44,60,61]. This chemical characteristic may be reflective of mantlemelt metasomatic reactions in post-orogenic, shoshonite-producing mantle, or indicate a growing influence of mantle plume components interacting with subduction-modified post-collisional lithosphere [41,61,68,76,78].…”

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 88%

“…Platinum-group elements (Ru, Rh, Ir, Pd, Pt) and Au were determined by ICP-MS after separation and pre-concentration by Na 2 O 2 fire-assay and tellurium co-precipitation following the method described in [40]. Additional details of the analytical procedures used in the current study can be found in [39,41].…”

Section: Methodsmentioning

confidence: 99%

“…Geochemical data have been traditionally successfully used to determine the possible sources and provenance of various (including strongly hydrothermally altered or metamorphosed) sedimentary formations as well as paleotectonic setting and geodynamic significance of volcanic sequences of different age [41,43,46,[50][51][52][53][54][55][56][57][58][59][60][61][62]. Major (K 2 O-Na 2 O-SiO 2 ) variations in black shale and volcaniclastic sediments from the Priorat DOQ region suggest their accumulation within a classic active continental margin setting, with three black shale samples plotting into the field of passive margin sediments (Figure 9A).…”

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

“…All compositional fields are derived from [60]. Average values for depleted mid-ocean ridge mantle source (DMM), enriched mid-ocean ridge basalt (E-MORB) and various enriched mantle components (EM1, EM2, HIMU, FOZO) follow the nomenclature of [41] and references therein. OIB-oceanic island basalts, OP MORB-oceanic plateau mid-ocean ridge basalt.…”

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

“…The presence of sills within the Paleozoic sedimentary sequence and general structural pattern of the Paleozoic basement of the Catalan Coastal Ranges (CCR) in the Priorat region is comparable with the sill-sediment complexes previously described in such classic extensional environments as the Gulf of California (essentially a young spreading center; [82]), the Faroe-Shetland Basin [83] and the sedimented slow-spreading Andaman Sea [84]. Extensional processes responsible for the generation of shoshonite melts within Andean-type active continental margins can occur in the frontal arc, intra-arc or back-arc geodynamic environment over a broad width of well-developed subduction-related arc-basin systems [41,58,[72][73][74]76,78,85,86]. Based on specific structural features, stratigraphy and regional tectonic evolution of the Paleozoic basement of the CCR [35][36][37][38]87,88], as well as our new geologic, mineralogical and geochemical data from the Priorat DOQ region, we suggest that Paleozoic sequences (at least in the southern and central portion of the CCR) were formed in moderate to deep (in terms of water depth) back-arc or intra-arc, partially anoxic (ubiquitous presence of black shale with framboidal pyrite and Fe-oxides; Figure 3) basins within a rifted Andean-type active continental margin.…”

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

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Nature of Paleozoic Basement of the Catalan Coastal Ranges (Spain) and Tectonic Setting of the Priorat DOQ Wine Terroir: Evidence from Volcanic and Sedimentary Rocks

et al. 2023

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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.

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Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

Section: Geochemical Constraints On the Nature Of The Paleozoic Basem...mentioning

confidence: 99%

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Nature of Paleozoic Basement of the Catalan Coastal Ranges (Spain) and Tectonic Setting of the Priorat DOQ Wine Terroir: Evidence from Volcanic and Sedimentary Rocks

et al. 2023

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Silver Mineralization in Deep Magmatogenic Systems of Ancient Island Arcs: The Ildeus Ultrabasic Massif, Stanovoy Mobile Belt (Russian Far East)

Kepezhinskas

Бердников

Krutikova

et al. 2023

Russ. J. of Pac. Geol.

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Magmatic Native Gold: Composition, Texture, Genesis, and Evolution in the Earth’s Crust

Berdnikov,

Kepezhinskas,

Nevstruyev

et al. 2024

Russian Geology and Geophysics

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––Here we report results of microforms’ studies of native gold and its alloys in igneous rocks, modified to varying degrees by secondary processes. We discuss the composition and occurrence of both the deep-seated magmatic gold-bearing alloys and the products of their transformation under conditions of the upper Earth’s crust. Gold-bearing Kamchatka adakites and ankaramites, Ildeus massif mafic-ultramafic intrusions and adakites from the Stanovoy fold system as well as dacites from the Bolivian Andes were formed during melting of either the suprasubduction mantle wedge or the subducted oceanic crust. In depleted peridotites from the Avachinsky Volcano in Kamchatka as well as suprasubduction ophiolites from Polar Urals, Eastern Sayan and the Western Mediterranean Betic–Rifean belt, the gold-bearing mantle was hybridized by subduction-related melts and high-temperature fluids. Volcanic rocks associated with the Lesser Khingan Fe–Mn deposits and Zolotaya Gora Au deposit in Southern Urals as well as Taragai ultramafic rocks in the South Khingan Range display subduction-related geochemical characteristics. Gold-bearing trachytes in the Virginian Appalachians (USA) represent felsic differentiates of mafic intraplate magmas. We propose that one of the principal forms of gold transport into the upper crustal environments is represented by Cu–Ag–Au alloys, which precipitated from mantle-derived silicate melt enriched in chalcophile and siderophile elements. Such Cu–Ag–Au alloy-rich magmatic rocks can either constitute primary sources of precious metals in the mantle-crust system or serve as geochemical precursors to the formation of native gold assemblages in epithermal and mesothermal ore deposits. Presence of magmatic gold particles in subduction-related igneous rocks and mantle restites hybridized by subduction-derived melts and high-temperature fluids suggest the existence of gold-rich horizons in the Earth’s mantle at depths comparable to typical depths of generation of primary convergent zone and some within-plate magmas.

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Native Metals and Alloys in Trachytes and Shoshonite from the Continental United States and High-K Dacite from the Bolivian Andes: Magmatic Origins of Ore Metals in Convergent and Within-Plate Tectonic Settings

Cited by 9 publications

References 76 publications

Nature of Paleozoic Basement of the Catalan Coastal Ranges (Spain) and Tectonic Setting of the Priorat DOQ Wine Terroir: Evidence from Volcanic and Sedimentary Rocks

Nature of Paleozoic Basement of the Catalan Coastal Ranges (Spain) and Tectonic Setting of the Priorat DOQ Wine Terroir: Evidence from Volcanic and Sedimentary Rocks

Silver Mineralization in Deep Magmatogenic Systems of Ancient Island Arcs: The Ildeus Ultrabasic Massif, Stanovoy Mobile Belt (Russian Far East)

Magmatic Native Gold: Composition, Texture, Genesis, and Evolution in the Earth’s Crust

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