Gold concentrations in metamorphic fluids: A LA-ICPMS study of fluid inclusions from the Alpine orogenic belt

Rauchenstein-Martinek, K.; Wagner, Thomas; Wälle, Marküs; Heinrich, Christoph A.

doi:10.1016/j.chemgeo.2014.07.018

Cited by 53 publications

(41 citation statements)

References 113 publications

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“…() and Rauchenstein‐Martinek et al . (). The multi‐element fluid inclusion LA‐ICPMS data are summarized in Table and illustrated in Figs (the full dataset including all microthermometric and LA‐ICPMS results for the individual FI grouped by assemblages and fluid inclusion types are listed in the Data S1).…”

Section: Fluid Inclusion Resultsmentioning

confidence: 97%

“…Some inclusions were analyzed for a smaller subset of elements focused on ore metals and are included here, but were published separately in Rauchenstein‐Martinek et al . ().…”

Section: Methodsmentioning

confidence: 97%

“…For minor elements such as the ore metals, concentrations in the fluid may be limited by availability in the source rocks, or in host rocks with which the fluids have interacted. Limited availability has been shown for the case of gold, where measured concentrations are lower by one to three orders of magnitude compared to those predicted from solubility calculations (Rauchenstein-Martinek et al 2014). Neither the thermodynamic data for all aqueous species nor the solubility-controlling phases of many trace metals that were analyzed in the fluid inclusions (e.g., Li, Rb, Cs, Sr, Ba, As, and Sb) are accurately known.…”

Section: Controls On Minor Element Concentrations In Metamorphic Fluidsmentioning

confidence: 99%

“…The detection limit for each element varied as a function of the size of the fluid inclusions, and some elements could therefore only be quantified in larger inclusions. Some inclusions were analyzed for a smaller subset of elements focused on ore metals and are included here, but were published separately in Rauchenstein-Martinek et al (2014).…”

Section: La-icpms Microanalysis Of Fluid Inclusionsmentioning

confidence: 99%

“…The elemental composition of 1007 individual fluid inclusions was analyzed by LA-ICPMS (192 from Gauli, 92 from Gerstenegg, 178 from Tiefengletscher, 57 from Vals, 62 from Bedretto, 220 from Cavagnoli, and 206 from Faido). The data were combined with those from Miron et al (2013) and Rauchenstein-Martinek et al (2014). The multi-element fluid inclusion LA-ICPMS data are summarized in Table 4 and illustrated in Figs 8-11 (the full dataset including all microthermometric and LA-ICPMS results for the individual FI grouped by assemblages and fluid inclusion types are listed in the Data S1).…”

Section: Elemental Composition Of Fluid Inclusionsmentioning

confidence: 99%

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Chemical evolution of metamorphic fluids in the Central Alps, Switzerland: insight from LA‐ICPMS analysis of fluid inclusions

Rauchenstein-Martinek

Wagner

Wälle

et al. 2016

Geofluids

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The chemical evolution of fluids in Alpine fissure veins (open cavities with large free‐standing crystals) has been studied by combination of fluid inclusion petrography, microthermometry, LA‐ICPMS microanalysis, and thermodynamic modeling. The quartz vein systems cover a metamorphic cross section through the Central Alps (Switzerland), ranging from subgreenschist‐ to amphibolite‐facies conditions. Fluid compositions change from aqueous inclusions in subgreenschist‐ and greenschist‐facies rocks to aqueous–carbonic inclusions in amphibolite‐facies rocks. The fluid composition is constant for each vein, across several fluid inclusion generations that record the growth history of the quartz crystals. Chemical solute geothermometry, fluid inclusion isochores, and constraints from fluid–mineral equilibria modeling were used to reconstruct the pressure–temperature conditions of the Alpine fissure veins and to compare them with the metamorphic path of their host rocks. The data demonstrate that fluids in the Aar massif were trapped close to the metamorphic peak whereas the fluids in the Penninic nappes record early cooling, consistent with retrograde alteration. The good agreement between the fluid–mineral equilibria modeling and observed fluid compositions and host‐rock mineralogy suggests that the fluid inclusions were entrapped under rock‐buffered conditions. The molar Cl/Br ratios of the fluid inclusions are below the seawater value and would require unrealistically high degrees of evaporation and subsequent dilution if they were derived from seawater. The halogen data may thus be better explained by interaction between metamorphic fluids and organic matter or graphite in metasedimentary rocks. The volatile content (CO2, sulfur) in the fluid inclusions increases systematically as function of the metamorphic grade, suggesting that the fluids have been produced by prograde devolatilization reactions. Only the fluids in the highest grade rocks were partly modified by retrograde fluid–rock interactions, and all major element compositions reflect equilibration with the local host rocks during the earliest stages of postmetamorphic uplift.

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Section: Fluid Inclusion Resultsmentioning

confidence: 97%

“…Some inclusions were analyzed for a smaller subset of elements focused on ore metals and are included here, but were published separately in Rauchenstein‐Martinek et al . ().…”

Section: Methodsmentioning

confidence: 97%

Section: Controls On Minor Element Concentrations In Metamorphic Fluidsmentioning

confidence: 99%

Section: La-icpms Microanalysis Of Fluid Inclusionsmentioning

confidence: 99%

Section: Elemental Composition Of Fluid Inclusionsmentioning

confidence: 99%

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Chemical evolution of metamorphic fluids in the Central Alps, Switzerland: insight from LA‐ICPMS analysis of fluid inclusions

Rauchenstein-Martinek

Wagner

Wälle

et al. 2016

Geofluids

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The Rare Earth Resources of Europe and Greenland

CHARLES,

TUDURI,

LEFEBVRE

et al. 2023

Metallic Resources 1

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Fluid evolution in a volcanic-hosted epithermal carbonate–base metal–gold vein system: Alto de la Blenda, Farallón Negro, Argentina

Márquez-Zavalía

Heinrich

2016

Miner Deposita

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Alto de la Blenda is an ~6.6 Ma intermediate-sulphidation epithermal vein system in the Farallón Negro Volcanic Complex, which also hosts the 7.1 Ma porphyry-Cu-Au deposit of Bajo de la Alumbrera. The epithermal vein system is characterised by large extent and continuity (2km x 400m open to depth x 6m maximum width) and an average gold grade of ~ 8 g/t. The vein is best developed within an intrusion of a finegrained equigranular monzonite, interpreted as the central conduit of a stratovolcano whose extrusive activity ended prior to porphyry-Cu-Au emplacement at Bajo de la Alumbrera, which is in turn cut by minor epithermal veins. The Alto de la Blenda vein consists predominantly of variably Mn-rich carbonates and quartz, with a few percent of pyrite , sphalerite, galena and other sulphide and sulphosalt minerals. Four phases of vein opening, hydrothermal mineralisation and repeated brecciation can be correlated between different vein segments. Stages This is the Green Open Access final manuscript to the paper originally published in Mineralium Deposita (2016) 51:873-902, made available by researchcollection.ethz.ch 2 2 and contain the greatest fraction of sulphide and gold. They are separated by the emplacement of a polymictic breccia containing clasts of quartz feldspar porphyry as well as basement rocks. Fluid inclusions in quartz related to stages 2 to 4 are liquid-rich with 2-4 wt% NaCl(eq). They homogenise between 160 and 300°C, with very consistent values within each assemblage. Vapour inclusions are practically absent in the epithermal vein. Quartz fragments in the polymictic breccia contain inclusions of intermediate to vapour-like density and similar low salinity (~ 3 wt% NaCleq), besides rare brine inclusions containing halite. LA-ICP-MS analyses of epithermal inclusions indicate high concentrations of K, Fe, As, Sb, Cs, and Pb that significantly vary within and through subsequent vein stages. Careful consideration of detection limits for individual inclusions show high gold concentrations of ~0.5 to 3 ppm dissolved in the ore fluid, which contains variably high sulfur concentrations in excess over Fe and other chalcophile metals. Compositional variations are interpreted to reflect cooling and contraction of lower-density magmatic fluids at depth, like those preserved in porphyry clasts that were mechanically transported up by the polymictic breccia. Ore mineral precipitation from the magmatic fluid occurred by further cooling and possibly minor mixing with surface-derived water, leading to sulphide saturation, de-sulphidation of the magmatic fluid and consequent gold precipitation. The absence of flash boiling and/or reduction by carbonaceous host rocks has led to relatively modest but constant gold grades in the carbonatebasemetalgold veins of Alto de la Blenda.

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Gold concentrations in metamorphic fluids: A LA-ICPMS study of fluid inclusions from the Alpine orogenic belt

Cited by 53 publications

References 113 publications

Chemical evolution of metamorphic fluids in the Central Alps, Switzerland: insight from LA‐ICPMS analysis of fluid inclusions

Chemical evolution of metamorphic fluids in the Central Alps, Switzerland: insight from LA‐ICPMS analysis of fluid inclusions

The Rare Earth Resources of Europe and Greenland

Fluid evolution in a volcanic-hosted epithermal carbonate–base metal–gold vein system: Alto de la Blenda, Farallón Negro, Argentina

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