Gold speciation and transport in geological fluids: insights from experiments and physical-chemical modelling

Pokrovski, Gleb S.; Akinfiev, N. N.; Borisova, Anastassia Y.; Зотов, А. В.; Kouzmanov, Kalin

doi:10.1144/sp402.4

Cited by 168 publications

(84 citation statements)

References 276 publications

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Section: Historical and Disciplinary Contextmentioning

confidence: 57%

“…Pyykko 2012). The affinity of gold with reduced sulphur in hydrothermal fluids was first experimentally demonstrated by Seward (1973), and has been confirmed in all subsequent experimental studies (see Pokrovski et al 2014).Gold-only deposits, including orogenic gold deposits, do appear to be products of hydrothermal fluids that are chemically distinct compared to fluids of other higher temperature hydrothermal ore deposit types, including porphyry deposits, epithermal deposits and greisens. Hypersaline fluids are absent at almost all deposits: The dominant fluid contains sufficient CO 2 to form a carbonic phase in fluid inclusions and has relatively low salinity.…”

mentioning

confidence: 68%

“…The authors present also up-to-date standard thermodynamic properties and HKF parameters for the best characterized aqueous complexes AuOH, AuCl 2 2 , AuHS and Au(HS) 2 2 , which can be used to compute Au solubilities up to 600 8C and 300 MPa. Pokrovski et al (2014) present also the most recent experimental data on Au complexes involving different sulphur forms, chloride and alkali metals, which are stable in high-temperature, sulphur-rich fluids, vapours and melts. These are Au complexes that significantly increase the Au solubility predicted by the aqueous species and that provide a more comprehensive description of the different conditions at which Au may be transported in the Earth's crust.…”

Section: Historical and Disciplinary Contextmentioning

confidence: 94%

“…Present volume: Gold-transporting hydrothermal fluids in the Earth's crust Pokrovski et al (2014) provide a comprehensive review of experimental and theoretical data on aqueous speciation, bulk solubility and partitioning of Au in major types of geofluids of the Earth's crust from relatively low-temperature solutions (25-200 8C) typical of geothermal-epithermal environments to supercritical magmatic fluids ( 400-800 8C), aqueous vapours and silicate melts. The authors present also up-to-date standard thermodynamic properties and HKF parameters for the best characterized aqueous complexes AuOH, AuCl 2 2 , AuHS and Au(HS) 2 2 , which can be used to compute Au solubilities up to 600 8C and 300 MPa.…”

Section: Historical and Disciplinary Contextmentioning

confidence: 99%

“…Using current experimental data on Au contents and partitioning in magmatic systems containing aqueous fluids, silicate melts and sulphide melts/ minerals, Pokrovski et al (2014) present a detailed discussion on the role of magmas in sourcing Au-bearing hydrothermal fluids. Such discussion considers in detail the new constraints on the major physical-chemical parameters (temperature, pressure, bulk salinity, pH, oxidation conditions) and fluid components (sulphur, carbon dioxide, arsenic) that affect Au concentration, transport, precipitation and partitioning in the crust.…”

Section: Historical and Disciplinary Contextmentioning

confidence: 99%

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Gold-transporting hydrothermal fluids in the Earth's crust: an introduction

Garofalo

Ridley

2014

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Hydrothermal ore deposits that are exploited for gold include both gold-only deposits, such as orogenic deposits, and gold-bearing examples of the common hydrothermal deposit types that are formed around upper-crustal magmatic centres, in particular porphyry and epithermal deposits. Fluid inclusion data have shown that ore fluids of gold-only deposits are compositionally distinct compared to fluids of other deposit types: Fluids of the latter deposit types are, in contrast, not distinctive, and recent research has been focussed on relating gold content to geochemical and petrological aspects of related magmatic systems and to fluid evolution on migration through the crust. This Special Publication includes an up-to-date summary of thermodynamic parameters of aqueous Au species at high temperatures and pressures, a dataset of fluid inclusion properties and compositions from orogenic deposits of different parts of the world, several comprehensive case studies of different types of gold deposits and their fluids from the USA, Brazil, Egypt, Slovakia and Bulgaria and numerical modelling aimed to define key parameters that affect fluid flow and gold deposition at a range of scales. Historical and disciplinary contextThe majority of gold deposits of the Earth's crust are generated by fluxes of hot aqueous (hydrothermal) fluids that are efficiently focussed within relatively small volumes of rock. A proportion of this gold is extracted from hydrothermal deposit types such as iron-oxide copper-gold (IOCG) deposits, porphyry deposits and low-and high-sulphidation epithermal deposits as a co-product with other metals, most commonly with copper or silver, the other Group 12 elements. A similar proportion is however a product of gold-only hydrothermal deposits, including orogenic gold-, intrusion-related gold-(IRGD) and Carlin-type gold deposits. In these gold-only deposit types, Au is in most cases not only the only commodity of economic interest in the ore, but we can infer from the available multi-element compositional data on fluid inclusions that it is the only commodity of interest transported in the hydrothermal fluids of these deposits (e.g. Yardley et al. 1993;Su et al. 2009). Gold-only hydrothermal deposits are thus environments in which gold is very effectively fractionated from other metals, presumably as a consequence of gold's unique chemical properties, such as high electronegativity and the tendency to form bonds with strong covalent character (e.g. Crerar et al. 1985), and the strength of relativistic effects on bonding behaviour (e.g. Pyykko 2012). The affinity of gold with reduced sulphur in hydrothermal fluids was first experimentally demonstrated by Seward (1973), and has been confirmed in all subsequent experimental studies (see Pokrovski et al. 2014).Gold-only deposits, including orogenic gold deposits, do appear to be products of hydrothermal fluids that are chemically distinct compared to fluids of other higher temperature hydrothermal ore deposit types, including porphyry deposits, epithe...

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Section: Historical and Disciplinary Contextmentioning

confidence: 57%

mentioning

confidence: 68%

Section: Historical and Disciplinary Contextmentioning

confidence: 94%

Section: Historical and Disciplinary Contextmentioning

confidence: 99%

Section: Historical and Disciplinary Contextmentioning

confidence: 99%

See 3 more Smart Citations

Gold-transporting hydrothermal fluids in the Earth's crust: an introduction

Garofalo

Ridley

2014

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Geochemistry

White

2017

Kirk-Othmer Encyclopedia of Chemical Technology

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Geochemistry is a subdiscipline of chemistry whose objective is understanding the processes occurring on and in the earth, its evolution, and its cosmic environment, and to using that understanding to better the human condition. It naturally divides into (a) low‐temperature or environmental geochemistry, focused on processes at or near the earth's solid surface, including the “critical zone,” the oceans, and the atmosphere, and (b) high‐temperature geochemistry focused on processes such as hydrothermal ore deposition, magmatism, and metamorphism. Isotope geochemistry takes advantage of naturally occurring variations in the isotopic composition of elements resulting from natural, nuclear, and chemical processes to further understand earth processes, both in the near‐surface environment and the earth's deep interior. Geochemistry has greatly enhanced our knowledge of nucleosynthesis, solar system formation, plate tectonics, geologic time, biological evolution, and human origins. Of particular interest in geochemistry are geochemical cycles, such as the carbon cycle, in which carbon in various chemical forms is cycled between the atmosphere, the biosphere, the ocean, sediments, and the earth's deep interior and in doing so regulates Earth's climate. Continuous geochemical research is necessary to ensure future supplies of resources critical to modern society and mitigation of the effects of recovery, use, and disposal of those resources that are critical to human health and happiness.

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Geology, sulfide geochemistry and supercritical venting at the Beebe Hydrothermal Vent Field, Cayman Trough

Webber

Roberts

Murton

et al. 2015

Geochem Geophys Geosyst

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The Beebe Vent Field (BVF) is the world's deepest known hydrothermal system, at 4960 m below sea level. Located on the Mid-Cayman Spreading Centre, Caribbean, the BVF hosts high temperature ( 4018C) ''black smoker'' vents that build Cu, Zn and Au-rich sulfide mounds and chimneys. The BVF is highly gold-rich, with Au values up to 93 ppm and an average Au:Ag ratio of 0.15. Gold precipitation is directly associated with diffuse flow through ''beehive'' chimneys. Significant mass-wasting of sulfide material at the BVF, accompanied by changes in metal content, results in metaliferous talus and sediment deposits. Situated on very thin (2-3 km thick) oceanic crust, at an ultraslow spreading centre, the hydrothermal system circulates fluids to a depth of 1.8 km in a basement that is likely to include a mixture of both mafic and ultramafic lithologies. We suggest hydrothermal interaction with chalcophile-bearing sulfides in the mantle rocks, together with precipitation of Au in beehive chimney structures, has resulted in the formation of a Au-rich volcanogenic massive sulfide (VMS) deposit. With its spatial distribution of deposit materials and metal contents, the BVF represents a modern day analogue for basalt hosted, Au-rich VMS systems.

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Gold speciation and transport in geological fluids: insights from experiments and physical-chemical modelling

Cited by 168 publications

References 276 publications

Gold-transporting hydrothermal fluids in the Earth's crust: an introduction

Gold-transporting hydrothermal fluids in the Earth's crust: an introduction

Geochemistry

Geology, sulfide geochemistry and supercritical venting at the Beebe Hydrothermal Vent Field, Cayman Trough

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