Hydrothermal Processes and Mineral Systems

Pirajno, Franco

doi:10.1007/978-1-4020-8613-7

Cited by 542 publications

(485 citation statements)

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“…The δ 34 S values for the ore-forming fluids range from 4.98 to 13.17‰, which is significantly larger than that of magmatic sulfur (0±1‰) (Pirajno, 2009). The range of S-isotopic compositions is closer to that reported for sedimentary rocks (Leach et al, 2005;Gregory et al, 2015), which implies that there was a sedimentary source for the sulfur, possibly with a magmatic contribution.…”

Section: 1source Of Metals and Ore-forming Fluidsmentioning

confidence: 80%

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Geology, geochronology and isotopic geochemistry of the Xiaoliugou W–Mo ore field in the Qilian Orogen, NW China: Case study of a skarn system formed during continental collision

Zheng

Ding

Cawood

et al. 2017

Ore Geology Reviews

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Section: 1source Of Metals and Ore-forming Fluidsmentioning

confidence: 80%

“…D-O isotopes can be used to trace the source of the mineralization fluids (e.g., Pirajno, 2009). The δ 18 O andδD values for the ore-forming fluids at Xiaoliugouare plotted in the diagram of Taylor (1974) (Fig.…”

Section: 1source Of Metals and Ore-forming Fluidsmentioning

confidence: 99%

Geology, geochronology and isotopic geochemistry of the Xiaoliugou W–Mo ore field in the Qilian Orogen, NW China: Case study of a skarn system formed during continental collision

Zheng

Ding

Cawood

et al. 2017

Ore Geology Reviews

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“…To aid in this purpose, detailed studies of the lithology and mineralogy of mineral deposits are important, and a number of conventional models have been proposed based on petrological and mineralogical studies including the determination of rock types, alteration zones, and minerals using thin/polished sections [1][2][3][4][5][6][7][8]. Based on this geological dataset, geological 3D models are then generated, plotting rock types, ore minerals, alteration zones, and stratigraphy [9,10].…”

Section: Introductionmentioning

confidence: 99%

Identification of mineralized zones in the Zardu area, Kushk SEDEX deposit (Central Iran), based on geological and multifractal modeling

et al. 2016

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Abstract:The aim of this paper is to delineate the different lead-zinc mineralized zones in the Zardu area of the Kushk zinc-lead stratabound SEDEX deposit, Central Iran, through concentration-volume (C-V) modeling of geological and lithogeochemical drillcore data. The geological model demonstrated that the massive sulfide and pyrite+dolomite ore types as main rock types hosting mineralization. The C-V fractal modeling used lead, zinc and iron geochemical data to outline four types of mineralized zones, which were then compared to the mineralized rock types identified in the geological model. 'Enriched' mineralized zones contain lead and zinc values higher than 6.93% and 19.95%, respectively, with iron values lower than 12.02%. Areas where lead and zinc values were higher than 1.58% and 5.88%, respectively, and iron grades lower than 22% are labelled "high-grade" mineralized zones, and these zones are linked to massive sulfide and pyrite+dolomite lithologies of the geological model. Weakly mineralized zones, labelled 'low-grade' in the C-V model have 0-0.63% lead, 0-3.16% zinc and > 30.19% iron, and are correlated to those lithological units labeled as gangue in the geological model, including shales and dolomites, pyritized dolomites. Finally, a log-ratio matrix was employed to validate the results obtained and check correlations between the geological and fractal modeling. Using this method, a high overall accuracy (OA) was confirmed for the correlation between the enriched and highgrade mineralized zones and two lithological units -the massive sulfide and pyrite+dolomite ore types.

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“…Hydrothermal solutions/fluids containing solutes derived from magmatic water or from the wall rock migrate upward and the changes in equilibrium with space and time allow the deposition of these solutes (Pirajno, 2009). Hydrothermally altered rocks have been extensively studied 3 especially in the context of ore formation, metal enrichment, and mineralization (Aiuppa et al, 2006;Allen and Hahn, 1994;Franzson et al, 2008;Halbach et al, 1993;Horton et al, 2001;Huston et al, 1995;Marques et al, 2010;Martin-Crespo et al, 2004;Ostwald and England, 1977;Pokrovski et al, 2007), but very few have investigated the potential leaching of toxic elements from these rocks when exposed to the environment.…”

Section: Introductionmentioning

confidence: 99%

The roles of pyrite and calcite in the mobilization of arsenic and lead from hydrothermally altered rocks excavated in Hokkaido, Japan

Tabelin¹,

Igarashi²,

Tamoto³

et al. 2012

Journal of Geochemical Exploration

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This paper describes the enrichment of hydrothermally altered volcanic and sedimentary rocks with arsenic (As) and lead (Pb), and the effects of pyrite and calcite on the mobilities and release mechanisms of these toxic elements under oxic and anoxic conditions. Enrichment of the altered rock with As and Pb predominantly occurred in precipitated pyrite grains and not on the alumino-silicate minerals making up the matrix of the rock. Arsenic was incorporated in pyrite grains formed during alteration in both volcanic and sedimentary rocks, but Pb was only found in the pyrite grains of the volcanic rock samples. When in contact with water, altered volcanic rocks had acidic pH while altered sedimentary rocks had alkaline pH. The mobilities of both As and Pb from the altered rocks were enhanced at acidic and alkaline pH and a minimum was observed in the circumneutral pH under both oxic and anoxic conditions. The absence of O 2 retarded the oxidation of pyrite most notably in the alkaline region but not in the acidic and circumneutral pH. The absence of CO 2 increased the pH of samples with significant calcite content but did not affect those containing substantial amounts of pyrite. Increasing the CO 2 also had insignificant effect on the concentrations of As and Pb in the leachate. The mechanisms controlling the mobilization of As and Pb from these rocks like dissolution of soluble secondary minerals, pyrite oxidation and adsorption were all related to pyrite while the pH of the rock when in contact with water was controlled by pyrite and calcite. Thus, excavated waste rocks that have been altered can be grouped based on the relative abundance of pyrite and calcite and their pH when in contact with water.

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Hydrothermal Processes and Mineral Systems

Cited by 542 publications

References 1 publication

Geology, geochronology and isotopic geochemistry of the Xiaoliugou W–Mo ore field in the Qilian Orogen, NW China: Case study of a skarn system formed during continental collision

Geology, geochronology and isotopic geochemistry of the Xiaoliugou W–Mo ore field in the Qilian Orogen, NW China: Case study of a skarn system formed during continental collision

Identification of mineralized zones in the Zardu area, Kushk SEDEX deposit (Central Iran), based on geological and multifractal modeling

The roles of pyrite and calcite in the mobilization of arsenic and lead from hydrothermally altered rocks excavated in Hokkaido, Japan

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