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M.d. Hannington - One of the best experts on this subject based on the ideXlab platform.
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13.18 – Volcanogenic Massive Sulfide Deposits
Treatise on Geochemistry, 2020Co-Authors: M.d. HanningtonAbstract:Volcanogenic Massive Sulfide (VMS) deposits, together with their close analogs, sedimentary-exhalative Massive Sulfide deposits, have accounted for more than half of global production of Zn and Pb, 7% of Cu, and a significant amount of silver, gold, and other by-product metals. This article examines the essential elements of the VMS genetic model as it pertains to the geochemistry of the deposits and the physical and chemical controls on ore deposition. The distribution, abundance, and classification of the deposits, the origins of the hydrothermal fluids, and the mineralogical, chemical, and isotopic characteristics of the ore and alteration are reviewed and discussed in the context of new knowledge from the modern seafloor.
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The minor element endowment of modern sea-floor Massive Sulfide deposits and comparison with deposits hosted in ancient volcanic successions
2020Co-Authors: Thomas Monecke, M.d. Hannington, Sven Petersen, Hannah Grant, I. SamsonAbstract:Sea-floor Massive Sulfide deposits represent a new type of base and precious metal resources that may be exploited by future deep-sea mining operations. These deposits occur in diverse tectonic environments and are mostly located along the global mid-ocean ridge system within international waters and arc-related settings within the exclusive economic zones of the world’s oceans. Much controversy is currently centered on the question whether sea-floor Massive Sulfide deposits represent a significant resource of metals that could be exploited to meet the metal demand of modern technology-based society. Chemical analysis of Sulfide samples from sea-floor hydrothermal vent sites worldwide shows that sea-floor Massive Sulfides can be enriched in the minor elements Bi, Cd, Ga, Ge, Hg, In, Mo, Sb, Se, Te, and Tl, with concentrations ranging up to several tens or hundreds of parts per million. The minor element content of seafloor Sulfides broadly varies with volcanic and tectonic setting. Massive Sulfides on mid-ocean ridges commonly show high concentrations of Se, Mo, and Te, whereas arc-related Sulfide deposits can be enriched in Cd, Hg, Sb, and Tl. Superposed on the volcanic and tectonic controls, the minor element content of sea-floor Sulfides is strongly influenced by the temperature-dependent solubility of these elements. The high- to intermediatetemperature suite of minor elements, Bi, In, Mo, Se, and Te, is typically enriched in Massive Sulfides composed of chalcopyrite, while the low-temperature suite of minor elements, Cd, Ga, Ge, Hg, Sb, and Tl, is more typically associated with sphalerite-rich Massive Sulfides. Temperature-related minor element enrichment trends observed in modern sea-floor hydrothermal systems are broadly comparable to those encountered in fossil Massive Sulfide deposits. Although knowledge on the mineralogical sequestration of the minor elements in sea-floor Massive Sulfide deposits is limited, a significant proportion of the total amount of minor elements contained in Massive Sulfides appears to be incorporated into the crystal structure of the main Sulfide minerals, including pyrite, pyrrhotite, chalcopyrite, sphalerite, wurtzite, and galena. In addition, the over 80 trace minerals recognized represent important hosts of minor elements in Massive Sulfides. As modern sea-floor Sulfides have not been affected by metamorphic recrystallization and remobilization, the minor element distribution and geometallurgical properties of the Massive Sulfides may differ from those of ancient Massive Sulfide deposits. The compilation of geochemical data from samples collected from hydrothermal vent sites worldwide now permits a first-order evaluation of the global minor element endowment of sea-floor Sulfide deposits. Based on an estimated 600 million metric tons (Mt) of Massive Sulfides in the neovolcanic zones of the world’s oceans, the amount of minor elements contained in sea-floor deposits is fairly small when compared to land-based mineral resources. Although some of the minor elements are potentially valuable commodities and could be recovered as co- or by-products from Sulfide concentrates, sea-floor Massive Sulfide deposits clearly do not represent a significant or strategic future resource for these elements.
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Seafloor Massive Sulfide deposits: Continuing efforts toward a global estimate of seafloor Massive Sulfides
OCEANS 2015 - Genova, 2015Co-Authors: M.d. Hannington, John Jamieson, Sven PetersenAbstract:In response to growing commercial interest in mining of seafloor Massive Sulfide (SMS) deposits, there has been ongoing debate about the possible global abundance of SMS [1,2,3,4]. The need for such assessments is now more urgent, as a number of countries, mining and exploration companies, and international consortia have begun to invest in intensive exploration campaigns for SMS. This paper examines the current inventory of SMS and considers the “next steps” in establishing the geological resources of Sulfide deposits that will be needed to sustain a new seafloor mining industry.
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constraints on water depth of Massive Sulfide formation evidence from modern seafloor hydrothermal systems in arc related settings
Economic Geology, 2014Co-Authors: Thomas Monecke, Sven Petersen, M.d. HanningtonAbstract:The results of three decades of seafloor research provide the most reliable information on the importance of water depth in Massive Sulfide formation. Available data from over 130 occurrences show that water depths of seafloor vent sites vary with plate tectonic setting and the regional magmatic and volcanic environment. The shallowest hydrothermal systems in subduction-related settings are hosted by arc volcanoes. These shallow vent sites have a number of features in common with subaerial epithermal systems. Massive Sulfide occurrences in arc-related rifts, the most likely setting for many ancient analogs, are generally restricted to water depths from ~700 to 2,000 m, with rifts developing within old arc crust at the deeper end of this range. Back-arc spreading centers proximal to arcs host Massive Sulfide deposits at depths of ~1,500 to 2,000 m. The deepest hydrothermal systems occur along mature back-arc spreading centers distal to volcanic arcs where water depths range from ~2,000 to 3,700 m. These deeper vent sites probably represent the best modern analogues of ophiolite-hosted Massive Sulfide deposits. Boiling of the hydrothermal fluids is common at volcanic arcs and in arc-related rifts. In these environments, elevated magmatic gas contents of the hydrothermal fluids can contribute to the widespread occurrence of phase separation and associated gas loss. By contrast, the high ambient pressures in deep marine hydrothermal systems along mature back-arc spreading centers prevent fluids from boiling during their ascent to the seafloor. Boiling controls the maximum temperature at which hydrothermal fluids discharge at the seafloor and, therefore, influences the metal content of seafloor Sulfide deposits. Copper-rich Massive Sulfides typically occur at water depths exceeding ~1,000 m, whereas Zn- and Pb-rich occurrences may form at any water depth. Boiling can be an important control on Ag and Au grades but is not the only factor controlling precious metal enrichment in Massive Sulfides. Shallow marine hot spring deposits can be highly enriched in trace metals such as As, Hg, and Sb. Submarine volcanic arc and back-arc settings are geologically complex and significant variations in water depth can occur over short distances. Paleoenvironmental reconstruction of these environments in ancient volcanic terranes is hampered by the lack of unequivocal volcanological or sedimentological criteria that indicate water depth. The relationships established here using modern seafloor observations provide important constraints on the paleoenvironmental setting of ancient volcanic-hosted Massive Sulfide deposits.
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the abundance of seafloor Massive Sulfide deposits
Geology, 2011Co-Authors: M.d. Hannington, John Jamieson, Thomas Monecke, Sven Petersen, Stace E BeaulieuAbstract:The possibility of mining seafl oor Massive Sulfide deposits has stirred debate about the sustainable use of this new resource and whether commercial development is worth the risk. Among the outstanding questions is how many deposits might be accessible to deep-sea mining. More than 300 sites of high-temperature hydrothermal venting have been identifi ed since the discovery of black smokers, but signifi cant Massive Sulfide accumulation has been found at only 165 of these sites. Estimates of the total number of vent fields and associated mineral deposits, based on plume studies and deposit occurrence models, range from 500 to 5000. We have used new deposit occurrence data from 10,000 km of ridge, arc, and backarc spreading centers to estimate the amount of Massive Sulfide in the easily accessible neovolcanic zones of the global oceans. The total accumulation in these areas is estimated to be on the order of 6 × 108 tonnes, containing ~3 × 107 tonnes of copper and zinc. This is similar to the total discovered copper and zinc in Cenozoic Massive sulfi de deposits mined on land but is insuffi cient to satisfy a growing global demand for these metals.
R. R. Large - One of the best experts on this subject based on the ideXlab platform.
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mineralogical features of ore diagenites in the urals Massive Sulfide deposits russia
Minerals, 2019Co-Authors: Valeriy V Maslennikov, Nataliya P. Safina, N. R. Ayupova, R. R. Large, A S Tseluyko, Irina Yu Melekestseva, Richard J Herrington, Vasiliy A Kotlyarov, Ivan A Blinov, S. P. MaslennikovaAbstract:In weakly metamorphosed Massive Sulfide deposits of the Urals (Dergamysh, Yubileynoe, Yaman-Kasy, Molodezhnoe, Valentorskoe, Aleksandrinskoe, Saf’yanovskoe), banded Sulfides (ore diagenites) are recognized as the products of seafloor supergene alteration (halmyrolysis) of fine-clastic Sulfide sediments and further diagenesis leading to the formation of authigenic mineralization. The ore diagenites are subdivided into pyrrhotite-, chalcopyrite-, bornite-, sphalerite-, barite- and hematite-rich types. The relative contents of sphalerite-, bornite- and barite-rich facies increases in the progression from ultramafic (=Atlantic) to bimodal mafic (=Uralian) and bimodal felsic (=Baymak and Rudny Altay) types of Massive Sulfide deposits. The ore diagenites have lost primary features within the ore clasts and dominantly exhibit replacement and neo-formed nodular microtextures. The evolution of the mineralogy is dependent on the original primary composition, sizes and proportions of the hydrothermal ore clasts mixed with lithic serpentinite and hyaloclastic volcanic fragments together with carbonaceous and calcareous fragments. Each type of ore diagenite is characterized by specific rare mineral assemblages: Cu–Co–Ni Sulfides are common in pyrrhotite-rich diagenites; tellurides and selenides in chalcopyrite-rich diagenites; minerals of the germanite group and Cu–Ag and Cu–Sn Sulfides in bornite-rich diagenites; abundant galena and sulfosalts in barite- and sphalerite-rich diagenites and diverse tellurides characterize hematite-rich diagenites. Native gold in variable amounts is typical of all types of diagenites.
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Criteria for the detection of hydrothermal ecosystem faunas in ores of Massive Sulfide deposits in the Urals
Lithology and Mineral Resources, 2017Co-Authors: V. V. Maslennikov, N. R. Ayupova, S. P. Maslennikova, A. Yu. Lein, A. S. Tseluiko, L. V. Danyushevsky, R. R. Large, V. A. SimonovAbstract:The ore-formational, ore-facies, lithological, and mineralogical-geochemical criteria are defined for the detection of hydrothermal ecosystem fauna in ores of the volcanic-hosted Massive Sulfide deposits in the Urals. Abundant mineralized microfauna is found mainly in Massive Sulfide mounds formed in the jasperous basalt (Buribai, Priorsk, Yubileinoe, Sultanov), rhyolite–basalt (Yaman-Kasy, Blyava, Komosomol’sk, Sibai, Molodezhnoe, Valentorsk), and the less common serpentinite (Dergamysh) formations of the Urals (O–D2). In the ore-formational series of the Massive Sulfide deposits, probability of the detection of mineralized fauna correlates inversely with the relative abundance of felsic volcanic rocks underlying the ores. This series is also marked by a gradual disappearance of colloform pyrite, marcasite, isocubanite, pyrrhotite, and pyrite pseudomorphoses after pyrrhotite; increase of the amount of bornite, fahlores, and barite; decrease of contents of Se, Te, Co, and Sn in chalcopyrite and sphalerite; and decrease of Tl, As, Sb, and Pb in the colloform pyrite. Probability of the detection of mineralized fauna in the morphogenetic series of Massive Sulfide deposits decreases from the weakly degraded Sulfide mounds to the clastic stratiform deposits. The degradation degree of Sulfide mounds and fauna preservation correlates with the attenuation of volcanic intensity, which is reflected in the abundance of sedimentary and volcanosedimentary rocks and the depletion of effusive rocks in the geological sections.
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se and in minerals in the submarine oxidation zone of a Massive Sulfide orebody of the molodezhnoe copper zinc Massive Sulfide deposit southern urals
Doklady Earth Sciences, 2017Co-Authors: N. R. Ayupova, V. V. Maslennikov, S. P. Maslennikova, L. V. Danyushevsky, V A Kotlyarov, R. R. LargeAbstract:For the first time, extremely high Se and In contents were determined for the pinches of Massive Sulfide orebodies that are composed of small-clastic layered Sulfide sediments transformed during submarine supergenesis. Se (clausthalite and naumannite) and In (roquesite) minerals were found. Hydrothermal chalcopyrite, a significant amount of which is present in the clasts of paleohydrothermal black smoker chimneys, was the source of Se. Most of the amount of In was contributed during dissolution of clasts of hydrothermal sphalerite, which is unstable in the submarine oxidation zone in the presence of oxidized pyrite.
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numerical heat and fluid flow modeling of the panorama volcanic hosted Massive Sulfide district western australia
Economic Geology, 2005Co-Authors: Christian Schardt, Jianwen Yang, R. R. LargeAbstract:Exceptional exposure of the Archean Pilbara block in Western Australia reveals a cross section through an Archean Massive Sulfide-hosting volcanic succession with underlying subvolcanic intrusion in the Panorama district. A numerical model based on available detailed geologic information has been constructed to simulate heat and fluid flow in the Panorama district. The modeling provides insight into the evolution of the hydrothermal system and evaluates key geologic parameters and their influence on fluid-flow, hydrothermal circulation, and the genesis of Massive Sulfide orebodies. The model simulates important aspects of the Panorama Massive Sulfide district, such as temperature distribution, relative alteration zonation, and the size and distribution of orebodies. Predicted temperatures ranging from 150oC at the top of the volcanic pile to ~400oC at the andesite-diorite interface are comparable to temperature estimates based on previously published oxygen isotope mapping. Modeled fluid discharge temperatures are highest for the Sulphur Springs deposit (300o–400oC) and lower for the Kangaroo Caves and other deposits (250o–350oC). The most favorable conditions to reproduce the orebodies and their related alteration zonation occur at anisotropic rock permeabilities comparable to the upper oceanic crust (10–15–10–14 m2) and higher fault permeabilities (10–14–10–13 m2) with a specific fault arrangement similar to that mapped in the field. The 4.6 million metric tons (Mt) Sulphur Springs orebody is predicted to form in less than 5,000 yr, assuming a hydrothermal fluid with seawater salinity, 10 ppm base metal concentration, and a low deposition efficiency (≤10%); other deposits form above the faults under similar conditions. A large range of base metal concentrations in the fluids can account for the known orebodies, but high temperatures (≥250oC) and high-flow velocities (>10–7 m/s) are necessary to produce the observed alteration patterns and distribution of ore deposits. Results indicate that the establishment of a significant hydrothermal system capable of forming economic Massive Sulfide deposits is favored in fresh volcanic rock packages that have not been affected by earlier compaction or alteration. Under these conditions, economic Massive Sulfide orebodies (>5 Mt of 10% Zn + Cu) may form in a few thousand years, although the overall lifespan of the hydrothermal system may be between 30,000 and ~200,000 yr, depending on the variations in rock and fault permeability with time.
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the alteration box plot a simple approach to understanding the relationship between alteration mineralogy and lithogeochemistry associated with volcanic hosted Massive Sulfide deposits
Economic Geology, 2001Co-Authors: R. R. Large, Holger Paulick, Bruce J Gemmell, David L. HustonAbstract:Zonal alteration is a common feature in volcanic rocks surrounding sea-floor Massive Sulfide deposits. Alteration indexes, such as the Ishikawa alteration index (AI) and the chlorite-carbonate-pyrite index (CCPI), have been developed to measure the intensity of sericite, chlorite, carbonate, and pyrite replacement of sodic feldspars and glass associated with hydrothermal alteration proximal to the orebodies. In this paper a simple graphical representation of the Ishikawa AI plotted against the CCPI, termed the "alteration box plot," is used to characterize the different alteration trends related to Massive Sulfide ores and to assist in the distinction of volcanic-hosted Massive Sulfide (VHMS)-related hydrothermal alteration from regional diagenetic alteration. Although there are some limitations with the technique, a series of case studies are used to demonstrate that the alteration box plot is a powerful means of understanding the relationship between mineralogy, lithogeochemistry, and intensity of alteration in zoned alteration systems related to VHMS deposits and should assist the exploration geologist in determining vectors to the center of the ore system.
David L. Huston - One of the best experts on this subject based on the ideXlab platform.
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metal leaching and inorganic sulfate reduction in volcanic hosted Massive Sulfide mineral systems evidence from the paleo archean panorama district western australia
Geology, 2001Co-Authors: David L. Huston, Carl W Brauhart, Susan L Drieberg, G J Davidson, David I GrovesAbstract:Comprehensive studies of the well-preserved, paleo-Arehean (3.6-3.2 Ga) Panorama volcanic-hosted Massive Sulfide district of Western Australla provide compelling evidence that metals were leached from the hase of the volcanic pile and redeposited at its top in volcanic-hosted Massive Sulfide deposits. This leaching provided more than enough metal to form known deposits, implying that direct magmatic input of metal is not required. Sulfur depletion from the base of the volcanic pile was associated with an increase in Fe2O3/FeO and hematitic alteration. These data, combined with sulfur isotope data, indicate that seawater sulfate reduction was facilitated by the olddation of rock FeO to hematite at high temperature in the H2S stability field. This is the first time that seawater sulfate reduction has been demonstrated regionally in an ancient volcanic-hosted Massive Sulfide mineral system. The data presented here require pah-Archean seawater to be sufate bearing.
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the alteration box plot a simple approach to understanding the relationship between alteration mineralogy and lithogeochemistry associated with volcanic hosted Massive Sulfide deposits
Economic Geology, 2001Co-Authors: R. R. Large, Holger Paulick, Bruce J Gemmell, David L. HustonAbstract:Zonal alteration is a common feature in volcanic rocks surrounding sea-floor Massive Sulfide deposits. Alteration indexes, such as the Ishikawa alteration index (AI) and the chlorite-carbonate-pyrite index (CCPI), have been developed to measure the intensity of sericite, chlorite, carbonate, and pyrite replacement of sodic feldspars and glass associated with hydrothermal alteration proximal to the orebodies. In this paper a simple graphical representation of the Ishikawa AI plotted against the CCPI, termed the "alteration box plot," is used to characterize the different alteration trends related to Massive Sulfide ores and to assist in the distinction of volcanic-hosted Massive Sulfide (VHMS)-related hydrothermal alteration from regional diagenetic alteration. Although there are some limitations with the technique, a series of case studies are used to demonstrate that the alteration box plot is a powerful means of understanding the relationship between mineralogy, lithogeochemistry, and intensity of alteration in zoned alteration systems related to VHMS deposits and should assist the exploration geologist in determining vectors to the center of the ore system.
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Zincian staurolite in the Dry River South volcanic-hosted Massive Sulfide deposit, northern Queensland, Australia: an assessment of its usefulness in exploration
Applied Geochemistry, 1995Co-Authors: David L. Huston, David J. PattersonAbstract:Abstract Staurolite from the Dry River South volcanic-hosted Massive Sulfide deposit in northern Queensland, Australia is enriched in ZnO (2.5–6.8%) only within the Massive Sulfide lens or in highly pyritic biotite-chlorite schist just below the Massive Sulfide lens. In the footwall alteration zone, staurolite ZnO levels vary between 0.4 and 1.3%, whereas in hanging wall metagraywackes and metapelites, the ZnO content is mainly below 1.0%. As staurolite from metapelitec rocks contains up to 7.9% ZnO, high ZnO levels in staurolite do not necessarily indicate a relationship to Zn-rich Massive Sulfide. Staurolite grains from the Dry River South amd other Massive Sulfide lenses have low TiO2 concentrations (mainly 0.4%). The low concentration of TiO2 in staurolite from the Massive Sulfide lens results from the low initial Ti concentration in exhalative ores. High ZnO and low TiO2 values are indicative of staurolite associated with Zn-rich Massive Sulfide. Zincian staurolite is a potential exploration indicator at both prospect and reconnaissance scales. At the prospect scale, zinc levels have potential in distinguishing true from false gossans, distinguishing low grade portions of Massive Sulfide lenses from barren Massive pyrite bodies, and characterizing alteration zones. At the reconnaissance scale, staurolite can be collected in the heavy mineral fraction of stream sediments, and multiple grains can be analyzed rapidly using modern electron microprobes.
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The compositon of pyrite in volcanogenic Massive Sulfide deposits as determined with the proton microprobe
Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms, 1993Co-Authors: David L. Huston, G.f. Suter, Chris RyanAbstract:Abstract Pixeprobe analysis of pyrite from Australian volcanogenic Massive Sulfide (VMS) deposits indicate significant levels of Cu, Zn, Pb, Ba, Ag, Sb, Bi (from inclusions). As, Tl, Mo, Au, In, Cd (from nonstoichiometric substitution), Co, Ni, Se and Te (from stoichiometric substitution). Pyrite in Massive Sulfide lenses is enriched in trace elements compared to that in the stringer zone owing to hydrothermal recrystallization. Metamorphic recrystallization also “cleans” pyrite of trace elements. High Au values occur in pyrite with high As content. Pyrite in stringer zones is enriched in Se relative to the overlying Massive Sulfide lenses and the surrounding alteration zones.
N. I. Eremin - One of the best experts on this subject based on the ideXlab platform.
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Selenium in Volcanogenic Massive Sulfide Ores
Doklady Earth Sciences, 2019Co-Authors: I. V. Vikent’ev, V P Moloshag, E V Belogub, N. I. EreminAbstract:This paper describes the Se proper minerals first identified in the primary ores in Uralian volcanogenic Massive Sulfide (VMS) deposits. The investigation was carried out by instrumental neutron activation analysis of bulk ore samples and the mineral monofractions and also by local analysis methods: LA-ICP-MS, electron microprobe analysis, and analytical electron microscopy. СSe reaches 977 ppm in the Uralian VMS ores. A significant positive correlation is characteristic for Se with Te, S, Fe, Co, Mo, Hg, and Bi. Se is concentrated in major Sulfides, mainly in pyrite (73 ppm), chalcopyrite (49 ppm), and pyrrhotite (48 ppm). Sphalerite commonly contains
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selenium in volcanogenic Massive Sulfide ores
Doklady Earth Sciences, 2019Co-Authors: I V Vikentev, N. I. Eremin, E V Belogub, V P MoloshagAbstract:This paper describes the Se proper minerals first identified in the primary ores in Uralian volcanogenic Massive Sulfide (VMS) deposits. The investigation was carried out by instrumental neutron activation analysis of bulk ore samples and the mineral monofractions and also by local analysis methods: LA-ICP-MS, electron microprobe analysis, and analytical electron microscopy. СSe reaches 977 ppm in the Uralian VMS ores. A significant positive correlation is characteristic for Se with Te, S, Fe, Co, Mo, Hg, and Bi. Se is concentrated in major Sulfides, mainly in pyrite (73 ppm), chalcopyrite (49 ppm), and pyrrhotite (48 ppm). Sphalerite commonly contains <10 ppm Se. The Se content is high (up to 1–3 wt %) in secondary and rare minerals of the Massive Sulfide ores (mainly Pb, Te, and Bi compounds): tetradymite, galena, tellurobismuthite, altaite, and wittichenite. In the ores, the Se proper minerals occur as kawazulite, clausthalite, and galena–clausthalite Pb(Se,S), and also as micron inclusions with (Ag,Cu)2(Se,S); (Ag,Pb)3(Te,Se)S; and (Ag,Pb)2(S,Se) compositions.
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Volcanogenic Massive Sulfide Deposits Enriched in Gold
Moscow University Geology Bulletin, 2018Co-Authors: A. L. Dergachev, N. I. EreminAbstract:Volcanogenic Massive Sulfide deposits contain not only Cu, Zn, and Pb, but Sb, Bi, Te, Se Ag, Co, other metals, and variable amounts of Ag and Au. In some of these, gold reserves exceed 100 t, while the gold grade reaches several dozens ppm. An original database was used to establish statistically meaningful criteria for identification of deposits with large gold reserves and/or that are anomalously enriched in gold. Some peculiar features of deposits with high Au grades were investigated, including their distribution in geological history and among the principal metallogenic provinces, as well as association with volcanogenic formations and paleovolcanic structures, geochemical and mineralogical features, and factors that caused enrichment in gold.
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Vanadium mineralization in ore of the Vihanti Massive Sulfide base-metal deposit, Finland
Doklady Earth Sciences, 2011Co-Authors: N. E. Sergeeva, N. I. Eremin, A. L. DergachevAbstract:A series of vanadium oxides—shcherbinaite, karelianite, kyzylkumite, coulsonite, and berdesinskiite—was found in association with pyrrhotite in pyrite-pyrrhotite ore from the Paleoproterozoic Vihanti Massive Sulfide deposit of the Kuroko-type. It is suggested that enrichment in vanadium of Massive Sulfide ore from the Vihanti deposit is a result of their metamorphogenic regeneration and pyrrhotinization at the expense of rocks and ore enriched in vanadium. The list of rare minerals in Massive Sulfide ore has been extended.
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Volcanogenic Massive Sulfide deposits of ophiolite associations
Moscow University Geology Bulletin, 2010Co-Authors: A. L. Dergachev, N. I. Eremin, N. E. SergeevaAbstract:Volcanogenic Massive Sulfide deposits in ophiolite complexes are usually attributed to the Cyprus type. They associate with basaltic volcanics that are formed in mid-ocean or back-arc spreading centers and much less frequently in intra-plate settings. The deposits are characterized by copper or copper-zinc ores that are enriched in Ni, Co, and in places Mn and As, but are very poor in Pb and demonstrate a low to moderate content of Ag and Au. Typically, the deposits are low to very low in ore and metal reserves. Cyprus-type deposits were irregularly distributed during geological history. The most ancient of them were formed in the Neoproterozoic, while the bulk of the deposits are Ordovician or Cretaceous in age. Their possible Paleoproterozoic analogues can be found in the Svecofennian belt (Outokumpu ore district), while modern ones are confined to the Explorer and Endeavour Ridges and southern segment of the Juan de Fuca Ridge.
Rodney Allen - One of the best experts on this subject based on the ideXlab platform.
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A thematic issue on the geological setting and genesis of volcanogenic Massive Sulfide (VMS) deposits
Mineralium Deposita, 2011Co-Authors: Rodney Allen, Fernando Tornos, Jan M. PeterAbstract:A thematic issue on the geological setting and genesis of volcanogenic Massive Sulfide (VMS) deposits
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setting of zn cu au ag Massive Sulfide deposits in the evolution and facies architecture of a 1 9 ga marine volcanic arc skellefte district sweden
Economic Geology, 1996Co-Authors: Rodney Allen, Par Weihed, Svenake SvensonAbstract:The Skellefte mining district occurs in an Early Proterozoic, mainly 1.90-1.87 Ga (Svecofennian) magmatic province of low to medium metamorphic grade in the Baltic Shield in northern Sweden. The district contains over 85 pyritic Zn-Cu-Au-Ag Massive Sulfide deposits and a few vein Au deposits and subeconomic porphyry Cu-Au-Mo deposits. The Massive Sulfide deposits mainly occur within, and especially along the top of, a regional felsic-dominant volcanic unit attributed to a stage of intense, extensional, continental margin arc volcanism. From facies analysis we interpret the paleogeography of this stage to have comprised many scattered islands and shallow-water areas, surrounded by deeper seas. All the major Massive Sulfide ores occur in below-wave base facies associations; however, some ores occur close to stratigraphic intervals of above-wave base facies associations, and the summits of some volcanoes that host Massive Sulfides emerged above sea level. Intense marine volcanism was superceded at different times in different parts of the district by a stage of reduced volcanism, uplift resulting in subregional disconformities, and then differential uplift and subsidence resulting in a complex horst and graben paleogeography. Uplift of the arc is attributed to the relaxation of crustal extension and the emplacement of granitoids to shallow crustal levels. A few Massive Sulfide ores formed within the basal strata of this second stage. The horst and graben system was filled by prograding fluvial-deltaic sediments and mainly mafic lavas, and during this stage the Skellefte district was a transitional area between renewed arc volcanism of more continental character to the north, and subsidence and basinal mudstone-turbidite sedimentation to the south. This whole volcanotectonic cycle occurred within 10 to 15 m.y.We define 26 main volcanic, sedimentary, and intrusive facies in the Skellefte district. The most abundant facies are (1) normal-graded pumiceous breccias, which are interpreted as syneruptive subaqueous mass flow units of pyroclastic debris, (2) porphyritic intrusions, and (3) mudstone and sandstone turbidites. Facies associations define seven main volcano types, which range from basaltic shields to andesite cones and rhyolite calderas. Despite this diversity of volcano types, most Massive Sulfide ores are associated with one volcano type: subaqueous rhyolite cryptodome-tuff volcanoes. These rhyolite volcanoes are 2 to 10 km in diameter, 250 to 1,200 m thick at the center, and are characterized by a small to moderate volume rhyolitic pyroclastic unit, intruded by rhyolite cryptodomes, sills, and dikes. Massive Sulfide ores occur near the top of the proximal (near vent) facies association. The remarkable coincidence in space and time between the ores and this volcano type indicates an intimate, genetic relationship between the ores and the magmatic evolution of the volcanoes.Many of the Massive Sulfide ores occur within rapidly emplaced volcaniclastic facies and are interpreted to have formed by infiltration and replacement of these facies. Some of the ore deposits have characteristics of both marine Massive Sulfides and subaerial epithermal deposits. We suggest that Massive Sulfides in the Skellefte district span a range in ore deposit style from deep-water sea-floor ores, to subsea-floor replacements, to shallow-water and possibly subaerial synvolcanic replacements. Facies models are provided for the mineralized rhyolite volcanoes and volcanological guides are provided for exploration for blind ores within these volcanoes.