Constraints of fluid inclusions and in-situ S-Pb isotopic compositions on the origin of the North Kostobe sediment-hosted gold deposit, eastern Kazakhstan

Wong, Kam-hung; Zhou, Mei‐Fu; Chen, Wei Terry; O’Brien, Hugh; Lahaye, Yann; Chan, Sik-Lap Jacky

doi:10.1016/j.oregeorev.2016.10.004

Cited by 16 publications

(5 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Pyrite standard has been utilized for SIMS and LA-MC-ICP-MS sulfur isotope analysis for marcasite in other studies (e.g., Rouxel et al, 2008;Wong et al, 2017).…”

Section: Sims Sulfur Isotope Analysismentioning

confidence: 99%

Metal remobilization and ore-fluid perturbation during episodic replacement of auriferous pyrite from an epizonal orogenic gold deposit

Evans

et al. 2019

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

Mineral-scale episodic replacement of auriferous pyrite by texturally-complex pyrite, marcasite and minor arsenopyrite occurred in breccia ores from the Daqiao epizonal orogenic gold deposit, West Qinling Orogen, China. This study uses a novel combination of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), Nanoscale secondary ion mass spectrometry (NanoSIMS), and secondary ion mass spectrometry (SIMS) to investigate the remobilization and re-concentration of gold and other trace elements during this complex replacement process and the probable mechanism. Several lines of evidence including some degree of preservation of external morphology, sharp contacts and compositional differences between the parent pyrite and product pyrite and marcasite, and reaction-induced porosity suggest that the replacement of parent pyrite proceeds via a two-step replacement via a dissolution and reprecipitation mechanism, plus an additional marcasite overgrowth. During the replacement of euhedral pyrite, depletion of gold and other trace elements (Te, Se, Zn, Co, Tl, Ni, W, and As) in porous product pyrite relative to its precursor indicate exsolution and remobilization of these metals from crystal lattice of the original pyrite. In the subsequent replacement of porous pyrite by two types of marcasite and minor arsenopyrite, euhedral product marcasite contains low contents of trace elements, possibly due to high metal solubility in the acidic fluids favorable for marcasite precipitation. The complex-zoned marcasite significantly enriched in gold and other metals relative to porous pyrite (W, Tl, As, Sb, Ag, Se, and Zn) is thought to have formed via precipitation triggered by further oxidation and/or immediate reduction in threshold supersaturation. Dissolution of the impurity-rich pyrite and precipitation of new pyrite and marcasite generations could have occurred at low pH plus high concentrations of dissolved Fe 2+ condition caused by partial oxidation of aqueous H2S and/or S 2in ore fluids. The fluid oxidation is evidenced by a general decreasing trend of δ 34 S values from the parent euhedral pyrite, to product porous pyrite, euhedral marcasite, and complex-zoned marcasite. The isotopic results are consistent with ore fluid oxidation controlled by pressure fluctuations during multistage hydraulic fracturing in a fault-valve regime at Daqiao deposit. This quantitative study emphasizes that the pressure-driven hydrothermal process plays a key role in the micron-to nano-scale redistribution and re-enrichment of gold and other trace metals during episodic replacement of auriferous pyrite in brittle rheological zones from epizonal orogenic gold systems.

show abstract

“…Pyrite standard has been utilized for SIMS and LA-MC-ICP-MS sulfur isotope analysis for marcasite in other studies (e.g., Rouxel et al, 2008;Wong et al, 2017).…”

Section: Sims Sulfur Isotope Analysismentioning

confidence: 99%

Metal remobilization and ore-fluid perturbation during episodic replacement of auriferous pyrite from an epizonal orogenic gold deposit

Evans

et al. 2019

Geochimica et Cosmochimica Acta

View full text Add to dashboard Cite

show abstract

“…The total S signal obtained for pyrite was typically 1.0-1.2 V. Under these conditions, after a 20 s baseline, 50-60 s of ablation is needed to obtain an internal precision of 34 S/ 32 S ≤ ± 0.000005 (1 SE). Three pyrite standards were used for external standard bracketing (PPP-1) (Gilbert et al, 2014) and quality control (Pyrite1 and Pyrite2 from GSF) of analyses (Wong et al, 2017). The measurement of the in-house Pyrite2 standard during the course of this study yielded the value of δ 34 SCDT (‰) of -0.2 ± 0.5 (1σ, n = 70), which within error is consistent with the reported value of -0.4 ± 0.5 (1σ) measured by gas mass spectrometry (Wong et al, 2017).…”

Section: La-mc-icp-ms Sulfur Isotope Analysismentioning

confidence: 99%

“…Three pyrite standards were used for external standard bracketing (PPP-1) (Gilbert et al, 2014) and quality control (Pyrite1 and Pyrite2 from GSF) of analyses (Wong et al, 2017). The measurement of the in-house Pyrite2 standard during the course of this study yielded the value of δ 34 SCDT (‰) of -0.2 ± 0.5 (1σ, n = 70), which within error is consistent with the reported value of -0.4 ± 0.5 (1σ) measured by gas mass spectrometry (Wong et al, 2017). These pyrite standards were appropriate for calibration of marcasite and even arsenopyrite sulfur isotope analyses (Prendergast et al, 2005), and there was no additional matrix fractionation correction applied for the marcasite herein.…”

Section: La-mc-icp-ms Sulfur Isotope Analysismentioning

confidence: 99%

Ore-Forming Processes of the Daqiao Epizonal Orogenic Gold Deposit, West Qinling Orogen, China: Constraints from Textures, Trace Elements, and Sulfur Isotopes of Pyrite and Marcasite, and Raman Spectroscopy of Carbonaceous Material

Evans

et al. 2018

Economic Geology

Self Cite

112

View full text Add to dashboard Cite

The Daqiao gold deposit is hosted in organic-rich Triassic pumpellyite-actinolite facies metamorphosed turbidites in the West Qinling Orogen, central China. Gold mineralization is characterized by high-grade hydraulic breccias (B and C ores) that overprint an earlier tectonic breccia (A ore). A complex paragenesis is defined by four sulfide stages: S1 diagenetic pre-ore pyrite (py), S2 hydrothermal early-ore disseminated pyrite and marcasite (mc), S3 main-ore pyrite and marcasite aggregates, and S4 late-ore coarse-grained marcasite with minor pyrite and stibnite. However, multiple generations of pyrite and marcasite may develop within one individual stage. Ore-related hydrothermal alteration is dominated by intensive silicification, sulfidation, sericitization, and generally distal minor carbonatization. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) trace element analyses show that the stage S1 py1 from the shale interlayers within turbidites contains low gold contents (mean of 0.05 ppm) and other trace elements (Mn, Co, Ni, Cu, Mo, Bi, and Pb) indicating an anoxic to euxinic sedimentary environment. Stage S2 contributed only minimally to the gold endowment with relatively low gold in various sulfides including py2 (mean of 0.09 ppm), py3 (0.84 ppm) to py4 (0.70 ppm), along with mc1 (0.02 ppm) and mc2 (0.14 ppm). Most of the gold was deposited in stage S3, which formed rapidly crystallized, irregular (e.g., framboids, colloform and cyclic zonation) cement-hosted py5a (mean of 27.35 ppm), py5b (9.71 ppm), and mc3 (5.94 ppm) during repeated hydraulic fracturing. Other trace elements (e.g., Ag, As, Sb, Hg, Tl, and W) are also significantly enriched in the main-ore stage pyrite and marcasite. Little or no gold is detected in the S4 py6 and mc4. Sulfur isotopes determined from in situ LA-MC-ICP-MS analyses of hydrothermal pyrite and marcasite from the Daqiao deposit vary significantly from-31.3 to +22.0‰ (δ 34 S values), but fall mostly between-10 to +10‰, and provide important information on the source and evolution of sulfur and of the ore-forming fluids. The results show that S2 ore fluids (mean δ 34 Ssulfide =-0.8 to +5.2‰) were most likely derived from deep-seated Paleozoic carbonaceous sediments during regional metamorphism associated with orogenesis of the West Qinling Orogen. Main-ore S3 ore fluids (mean δ 34 Ssulfide =-9.7 to-6.0‰) are relatively depleted in 34 S relative to those of S2, presumably due to fluid oxidation associated with hydraulic fracturing caused by the over pressurized fluids. The textural, chemical, and isotopic data indicate two distinct gold-introducing episodes at Daqiao, forming sulfide disseminations during early-ore S2 and cement-hosted sulfide aggregates during main-ore S3. The S2 mineralization took place in a tectonic breccia beneath low-permeability shale seals that capped the flow of deep-seated metamorphic fluids, facilitating reaction with pre-existing carbonaceous material and the host turbidites to form sulfide disseminations and pervasive silicific...

show abstract

“…The 206 Pb/ 204 Pb ratios of the sulfides are distinctly lower than those reported for the mantle ( 206 Pb/ 204 Pb = 18.010; Doe and Zartman, 1979), 207 Pb/ 204 Pb ratios are similar to those of the mantle (<15.600, Shen, 1997), and 208 Pb/ 204 Pb ratios are slightly lower than those of the mantle ( 208 Pb/ 204 Pb = 37.700; Doe and Zartman, 1979). The mantle‐Pb affinity could be attributed to syn/post‐tectonic magmatic activity (e.g., hidden plutons) during the convergence of continental margins (Wong et al ., 2017). Therefore, the measured Pb isotope data suggest that the Pb at Xinfang was primarily sourced from deep magma.…”

Section: Discussionmentioning

confidence: 99%

A magmatic‐hydrothermal origin of the Xinfang gold deposit, Liaodong Peninsula, China, revealed by in‐situ S–Pb isotopes and trace element analyses of pyrite

Zeng

Frimmel

et al. 2021

Resource Geology

View full text Add to dashboard Cite

The Xinfang deposit is a large gold deposit (>20 t of Au) on the southern edge of the Liaodong Peninsula, China. A total of 37 gold‐bearing orebodies are identified along NS‐ and NW‐striking faults and are mainly hosted by the Archean and Neoproterozoic metamorphic rocks. Three stages of hydrothermal mineralization are distinguished, including Stage I of dominant quartz ± pyrite (Py1), Stage II of quartz‐polymetallic sulfide (Py2), and Stage III of quartz‐calcite ± pyrite (Py3). Gold primarily occurs at the Stage II in association with intensive silicification, pyritization, and sericitization. Here, we report on high‐precision in‐situ LA‐MC‐ICP‐MS analyses of S and Pb isotopic compositions of the sulfide minerals and LA‐ICP‐MS analyses of trace element signature of the pyrite from the Xinfang gold deposit. The δ34S values of the sulfides range from 1.3 to 5.3‰, which is consistent with a magmatic origin of S. The sulfides yield 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb ratios of 37.497–37.773, 15.323–15.410, and 17.004–17.229, respectively, which deviate from the values of the wall rocks, suggesting an external Pb source. The in‐situ LA‐ICP‐MS spot analyses of the pyrite reveals that gold occurs in two generations of pyrite (Py2 and Py3) but at low concentrations (≤0.06 ppm for Py2, ≤0.24 ppm for Py3). Visible gold, however, only occurs in the Stage II assemblage as inclusions in pyrite and quartz, and is distributed along the margins or within the fractures of the sulfides. The Py2 shows high Co, Ni, and As concentrations and is depleted in other trace elements typical of a magmatic‐hydrothermal derivation. In contrast, Py3 exhibits low concentrations in most trace elements. Trace element mapping of Py2 revealed correlations between Fe and Co, as well as Ni and As, indicating their couped substitution in the pyrite structure. The available geological, petrographic and geochemical data consistently suggest that the Xinfang gold deposit formed during the Early Cretaceous by hydrothermal fluids of magmatic contribution.

show abstract

Constraints of fluid inclusions and in-situ S-Pb isotopic compositions on the origin of the North Kostobe sediment-hosted gold deposit, eastern Kazakhstan

Cited by 16 publications

References 54 publications

Metal remobilization and ore-fluid perturbation during episodic replacement of auriferous pyrite from an epizonal orogenic gold deposit

Metal remobilization and ore-fluid perturbation during episodic replacement of auriferous pyrite from an epizonal orogenic gold deposit

Ore-Forming Processes of the Daqiao Epizonal Orogenic Gold Deposit, West Qinling Orogen, China: Constraints from Textures, Trace Elements, and Sulfur Isotopes of Pyrite and Marcasite, and Raman Spectroscopy of Carbonaceous Material

A magmatic‐hydrothermal origin of the Xinfang gold deposit, Liaodong Peninsula, China, revealed by in‐situ S–Pb isotopes and trace element analyses of pyrite

Contact Info

Product

Resources

About