Magmatic–hydrothermal origin of Nevada’s Carlin-type gold deposits

Muntean, John L.; Cline, Jean S.; Simon, Adam C.; Longo, Anthony A.

doi:10.1038/ngeo1064

Cited by 284 publications

(112 citation statements)

References 34 publications

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“…Such patterns contribute, along with other possible factors evoked so far, such as magma-fluid and vapor-brine separation (3,16,30), to the large spatial variations of Au grades and Au/Cu ratios reported between porphyry deposits. Furthermore, the S − 3 may also control incorporation of Au in a chemically bound state into pyrite, which is the major Au host of many epithermal and Carlin-type deposits (8,38). Because pyrite formation from hydrothermal solution occurs via polysulfide ion precursors (43), S − 3 may play a key role in this mechanism, favoring Au uptake by the sulfide mineral from solutions undersaturated with metallic gold.…”

Section: Discussion and Geological And Metallogenic Applicationsmentioning

confidence: 99%

Sulfur radical species form gold deposits on Earth

Pokrovski

Kokh

Guillaume

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

121

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Current models of the formation and distribution of gold deposits on Earth are based on the long-standing paradigm that hydrogen sulfide and chloride are the ligands responsible for gold mobilization and precipitation by fluids across the lithosphere. Here we challenge this view by demonstrating, using in situ X-ray absorption spectroscopy and solubility measurements, coupled with molecular dynamics and thermodynamic simulations, that sulfur radical species, such as the trisulfur ion S − 3 , form very stable and soluble complexes with Au + in aqueous solution at elevated temperatures (>250°C) and pressures (>100 bar). These species enable extraction, transport, and focused precipitation of gold by sulfur-rich fluids 10-100 times more efficiently than sulfide and chloride only. As a result, S − 3 exerts an important control on the source, concentration, and distribution of gold in its major economic deposits from magmatic, hydrothermal, and metamorphic settings. The growth and decay of S − 3 during the fluid generation and evolution is one of the key factors that determine the fate of gold in the lithosphere.gold | sulfur | ore deposit | hydrothermal fluid | trisulfur ion

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Section: Discussion and Geological And Metallogenic Applicationsmentioning

confidence: 99%

Sulfur radical species form gold deposits on Earth

Pokrovski

Kokh

Guillaume

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

121

View full text Add to dashboard Cite

show abstract

“…Drilling in the study area and the previous works (Cline et al 2005;Muntean et al 2011Muntean et al , 2007Thoreson et al 2000) suggest that cover rocks include unconsolidated sediments, valley-filled sediment, alluvium and interbeds of volcanics. The cover sequences are considered to be less prospective for primary gold, while basalt, mudstone, quartzite and tuff are prevalent in the Palaeozoic basement rocks.…”

Section: A Field Examplementioning

confidence: 99%

“…It is estimated that they contain approximately six million kilograms of gold, making them the second largest accumulation in the world. It accounts for 6 % of annual worldwide gold production (Muntean et al 2011). Carlin-style gold deposits have been actively mined since 1961, although some earlier deposits were exploited at the beginning of the twentieth century (Cline et al 2005).…”

Section: A Field Examplementioning

confidence: 99%

“…Carlin-style gold deposits have been actively mined since 1961, although some earlier deposits were exploited at the beginning of the twentieth century (Cline et al 2005). Palaeozoic rocks are the main host for Carlin-style gold deposits with Eocene-aged mineralisation (Cline et al 2005;Muntean et al 2011). The data used for this research were collected over an area with large variations in cover thickness.…”

Section: A Field Examplementioning

confidence: 99%

“…Cover depths range from less than 100 m to more than 500 m, and the base of the cover sequence often has a sharp clear geo-electrical transition to more electrically resistive basement. The transition between cover and basement is an unconformity between Palaeozoic sediments that we define as ''basement'' and the younger ''cover'' sequences (Cline et al 2005;Muntean et al 2011Muntean et al , 2007Thoreson et al 2000).…”

Section: A Field Examplementioning

confidence: 99%

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Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Harris

Pethick

et al. 2016

Surv Geophys

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Natural source electromagnetic methods have the potential to recover rock property distributions from the surface to great depths. Unfortunately, results in complex 3D geo-electrical settings can be disappointing, especially where significant near-surface conductivity variations exist. In such settings, unconstrained inversion of magnetotelluric data is inexorably non-unique. We believe that: (1) correctly introduced information from seismic reflection can substantially improve MT inversion, (2) a cooperative inversion approach can be automated, and (3) massively parallel computing can make such a process viable. Nine inversion strategies including baseline unconstrained inversion and new automated/semiautomated cooperative inversion approaches are applied to industry-scale co-located 3D seismic and magnetotelluric data sets. These data sets were acquired in one of the Carlin gold deposit districts in north-central Nevada, USA. In our approach, seismic information feeds directly into the creation of sets of prior conductivity model and covariance coefficient distributions. We demonstrate how statistical analysis of the 123Surv Geophys (2016) 37:845-896 DOI 10.1007/s10712-016-9377-z distribution of selected seismic attributes can be used to automatically extract subvolumes that form the framework for prior model 3D conductivity distribution. Our cooperative inversion strategies result in detailed subsurface conductivity distributions that are consistent with seismic, electrical logs and geochemical analysis of cores. Such 3D conductivity distributions would be expected to provide clues to 3D velocity structures that could feed back into full seismic inversion for an iterative practical and truly cooperative inversion process. We anticipate that, with the aid of parallel computing, cooperative inversion of seismic and magnetotelluric data can be fully automated, and we hold confidence that significant and practical advances in this direction have been accomplished.

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Trace elements and in situ sulfur isotopes of pyrite from the Baiyunpu Au deposit in central Hunan, South China: Implications for gold mineralization

Gao

Shen

et al. 2022

Geological Journal

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The Central Hunan metallogenic province, located in the southeastern part of the Yangtze Block, South China, is one of the most important Sb–Au metallogenic belts in China. The Baiyunpu gold deposit is one of the important Carlin‐type gold deposits occurring in Devonian sedimentary strata in Central Hunan. Optical microscopy and in situ laser ablation (multi‐collector) inductively coupled plasma mass spectrometry (LA‐[MC]‐ICP‐MS) are used to determine the texture, trace element compositions and sulfur isotope for pyrites from the pre‐ore and syn‐ore stages to constrain the sources of reduced sulfur and metals and the mechanism of gold precipitation. Four generations of pyrite were identified by petrography and pyrite compositions. Pre‐ore Py1 is characterized by relatively low concentrations of As, Au, Sb and Cu and high concentrations of Co, Ni, Bi and Pb. Py1 has positive δ34S values of 6.5–10.1‰, which we ascribe to a bacterial reduction of marine sulfate in closed marine systems, or from weak Rayleigh fractionation by bacterial sulfate reduction (BSR) or thermochemical sulfate reduction (TSR) during sedimentary‐diagenetic processes. Pre‐ore Py2 presents as rims of Py1 and contains relatively high As (69,530 ppm), Sb (123.2 ppm) and low Au (4.89 ppm). Compared with Py2, Py3 has relatively high Au (194.4 ppm) and Cu (24.6 ppm) and low As (40,801 ppm). We interpret that Py2 and Py3 could have precipitated from an Au‐free but As‐rich early hydrothermal fluids or from low‐Au and As‐rich fluids at the beginning of the ore stage. The δ34S values of Py2 and Py3 in the Baiyunpu deposit are concentrated in a narrow range of −1.2 to 1.2‰, suggesting the involvement of magmatic sulfur. Syn‐ore pyrites (Opy) are enriched in Au (517.8 ppm), As (39,719 ppm), Cu (261.9 ppm) and Sb (171.4 ppm). Irregular boundaries between Py1 and Opy suggest that the replacement may have been important for the formation of pyrites at the syn‐ore stage. The variation of As concentration in Opy1, Opy2 and Opy3 appear to have recorded fluctuations in the chemical composition of ore fluids. The δ34S values of Opy (0.1–5.9‰) are slightly higher than Py2 and Py3 due to mixing with sedimentary components with elevated δ34S values in late‐stage hydrothermal fluids. Profile analyses for Baiyunpu auriferous pyrite grains suggest that Au was positively correlated with Cu, but not with As. The correlation between Au, Cu and As in Opy may be dominated by their concentrations of ambient evolving fluids.

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Magmatic–hydrothermal origin of Nevada’s Carlin-type gold deposits

Cited by 284 publications

References 34 publications

Sulfur radical species form gold deposits on Earth

Sulfur radical species form gold deposits on Earth

Semiautomatic and Automatic Cooperative Inversion of Seismic and Magnetotelluric Data

Trace elements and in situ sulfur isotopes of pyrite from the Baiyunpu Au deposit in central Hunan, South China: Implications for gold mineralization

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