Micro-Fourier Transform Infrared (FT-IR) and δD value investigation of hydrothermal vein quartz: Interpretation of fluid inclusion δD values in hydrothermal systems

Gleeson, Sarah A.; Roberts, Stephen; Fallick, Anthony E.; Boyce, Adrian J.

doi:10.1016/j.gca.2008.06.014

Cited by 15 publications

(8 citation statements)

References 28 publications

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“…The amount of hydrogen present in quartz is principally a function of the abundance of fluid inclusions, although some structurally--bound OH can exist. Although fluid inclusion extraction by thermal decrepitation is prone to generating artificially low δD (Faure, 2003), it has been shown that heating at ≤750°C (as per our methodology, see Appendix 1) may be reliable, particularly where hydrogen yields are greater than ~0.05 µmol/mg quartz (e.g., Gleeson et al, 2008). In our study, yields were above this value (0.09 µmol/mg; Table 2) suggesting that the results might be reliable.…”

Section: Fluid Inclusionsmentioning

confidence: 48%

Magmatic Fluids Implicated in the Formation of Propylitic Alteration: Oxygen, Hydrogen, and Strontium Isotope Constraints from the Northparkes Porphyry Cu-Au District, New South Wales, Australia

et al. 2020

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In porphyry ore deposit models, the propylitic alteration facies is widely interpreted to be caused by convective circulation of meteoric waters. However, recent field-based and geochemical data suggest that magmatic-derived fluids are likely to contribute to development of the propylitic assemblage. In order to test this hypothesis, we determined the oxygen and hydrogen isotope compositions of propylitic mineral separates (epidote, chlorite, and quartz), selected potassic mineral separates (quartz and magnetite), and quartz-hosted fluid inclusions from around the E48 and E26 deposits in the Northparkes porphyry Cu-Au district, New South Wales, Australia. In addition, the strontium isotope composition of epidote was determined to test for the potential contribution of seawater in the Northparkes system given the postulated island-arc setting and submarine character of some country rocks. Oxygen isotope geothermometry calculations indicate potassic alteration occurred between ~600° and 700°C in magmatic/mineralized centers, persisting to ~450°C upon lateral transition into propylitic alteration. Across the propylitic facies, temperature progressively decreased outward to <250°C. These temperature estimates and additional data from chlorite geothermometry were utilized to calculate the oxygen and hydrogen isotope composition of the fluid in equilibrium with the sampled minerals. Results show that propylitic fluids spanned a range of compositions with δ18O between 0.5 and 3.7‰ and δD between –49 and –17‰. Comparison of these results with the modeled compositions of meteoric and/or magmatic fluids during their evolution and isotopic exchange with local country rocks shows that a magmatic fluid component must exist across the propylitic halo during its formation. Strontium isotope data from propylitic epidote provide initial (based on formation at ~450 Ma) 87Sr/86Sr values in the range of 0.704099 to 0.704354, ruling out the presence of seawater as a second fluid in the system. Although we cannot exclude magmatic-meteoric mixing, especially toward the fringes of the system, our results support a model in which magmatic-derived fluid is the primary driver of propylitic alteration as it undergoes cooling and chemical equilibration during outward infiltration into country rocks. This is consistent with chemical mass transfer calculations for Northparkes and published chemical-thermodynamic models that only require a magmatic fluid for the production of propylitic assemblages. In view of this and supporting data from other deposits, we suggest that magmatic fluids are essential drivers of propylitic alteration in porphyry systems.

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Section: Fluid Inclusionsmentioning

confidence: 48%

Magmatic Fluids Implicated in the Formation of Propylitic Alteration: Oxygen, Hydrogen, and Strontium Isotope Constraints from the Northparkes Porphyry Cu-Au District, New South Wales, Australia

et al. 2020

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“…Onegram bulk samples of quartz were analyzed using the method of Donnelly et al (2001) and a VG-Micromass Optima mass spectrometer. Samples were heated to a maximum of 700°C to release included fluids (but not molecular hydroxides; Gleeson et al, 2008). Results are reported in standard notation (δD) as ‰ deviations from V-SMOW.…”

Section: Stable Isotopesmentioning

confidence: 99%

Rhenium Enrichment in the Muratdere Cu-Mo (Au-Re) Porphyry Deposit, Turkey: Evidence from Stable Isotope Analyses (δ34S, δ18O, δD) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Analysis of Sulfides

et al. 2019

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The Muratdere Cu-Mo (Au) porphyry deposit in western Turkey contains elevated levels of rhenium and is hosted within granodioritic intrusions into an ophiolitic mélange sequence in the Anatolian belt. The deposit contains several stages of mineralization: early microfracture-hosted molybdenite and chalcopyrite, followed by a quartz-pyrite-chalcopyrite vein set associated with Cu-Au grade, a quartz-chalcopyrite-pyrite-molybdenite vein set associated with Cu-Mo-Re grade, and a later polymetallic quartz-barite-sphalerite-galena-pyrite vein set. The rhenium in Muratdere is hosted within two generations of molybdenite: early microfracture-hosted molybdenite and later vein-hosted molybdenite. In situ laser ablation-inductively coupled plasma-mass spectrometry analysis of sulfides shows that the later molybdenite has significantly higher concentrations of Re (average 1,124 ppm, σ = 730 ppm, n = 43) than the early microfracture-hosted molybdenite (average 566 ppm, σ = 423 ppm, n = 28). Pyrite crystals associated with the Re-rich molybdenite have higher Co and As concentrations than those in other vein sets, with Au associated with As. The microfracture-hosted sulfides have δ34S values between −2.2‰ and +4.6‰, consistent with a magmatic source. The vein-hosted sulfides associated with the high-Re molybdenite have a δ34S signature of 5.6‰ to 8.8‰, similar to values found in peridotite lenses in the Anatolian belt. The later enrichment in Re and δ34S-enriched S may be sourced from the surrounding ophiolitic country rock or may be the result of changing redox conditions during deposit formation.

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“…1 g of the quartz separate was analyzed using the method of Donnelly et al (2001) and a VG-Micromass Optima mass spectrometer. Samples are heated to a maximum of 700°C to release the fluids from fluid inclusions (but not molecular hydroxides; Gleeson et al, 2008). Results are reported in standard notation (δD) as per mil (‰) deviations from Vienna Standard Mean Ocean Water (V-SMOW).…”

Section: Quartz Isotope Analysismentioning

confidence: 99%

Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda

Daele

Hulsbosch

Dewaele

et al. 2018

Ore Geology Reviews

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The fluid sources of granite-related Sn-quartz vein deposits are commonly obscured by fluid mixing or fluid-rock interactions. As a result, fluid inclusions, minerals and isotopes in these veins indicate an intermediate composition between magmatic and metamorphic, but the degree of mixing between Highlights  Peribatholitic Sn-quartz veins often show secondary overprinting signatures.  Fluid mixing was quantified by muscovite and fluid inclusion geochemistry  Fluid mixing plays an important role in the genesis of Sn-quartz veins.

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Micro-Fourier Transform Infrared (FT-IR) and δD value investigation of hydrothermal vein quartz: Interpretation of fluid inclusion δD values in hydrothermal systems

Cited by 15 publications

References 28 publications

Magmatic Fluids Implicated in the Formation of Propylitic Alteration: Oxygen, Hydrogen, and Strontium Isotope Constraints from the Northparkes Porphyry Cu-Au District, New South Wales, Australia

Magmatic Fluids Implicated in the Formation of Propylitic Alteration: Oxygen, Hydrogen, and Strontium Isotope Constraints from the Northparkes Porphyry Cu-Au District, New South Wales, Australia

Rhenium Enrichment in the Muratdere Cu-Mo (Au-Re) Porphyry Deposit, Turkey: Evidence from Stable Isotope Analyses (δ34S, δ18O, δD) and Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Analysis of Sulfides

Mixing of magmatic-hydrothermal and metamorphic fluids and the origin of peribatholitic Sn vein-type deposits in Rwanda

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