Curtin University Homepage
  • Library
  • Help
    • Admin

    espace - Curtin’s institutional repository

    JavaScript is disabled for your browser. Some features of this site may not work without it.
    View Item 
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item
    • espace Home
    • espace
    • Curtin Research Publications
    • View Item

    Crude oils as ore fluids: An experimental in-situ XAS study of gold partitioning between brine and organic fluid from 25 to 250°C

    Access Status
    Fulltext not available
    Authors
    Crede, L.
    Liu, W.
    Evans, Katy
    Rempel, Kirsten
    Testemale, D.
    Brugger, J.
    Date
    2019
    Type
    Journal Article
    
    Metadata
    Show full item record
    Citation
    Crede, L. and Liu, W. and Evans, K. and Rempel, K. and Testemale, D. and Brugger, J. 2019. Crude oils as ore fluids: An experimental in-situ XAS study of gold partitioning between brine and organic fluid from 25 to 250°C. Geochimica Et Cosmochimica Acta. 244: pp. 352-365.
    Source Title
    Geochimica Et Cosmochimica Acta
    DOI
    10.1016/j.gca.2018.10.007
    ISSN
    0016-7037
    School
    School of Earth and Planetary Sciences (EPS)
    Funding and Sponsorship
    http://purl.org/au-research/grants/arc/DP140103995
    URI
    http://hdl.handle.net/20.500.11937/73307
    Collection
    • Curtin Research Publications
    Abstract

    Organic matter can be associated with mineralization in hydrothermal ore deposits. One hypothesis is that this organic matter represents remnants of organic fluids (crude oils) that were competing with aqueous fluids for metal transport and contributed to metal endowment. We investigated the transport of gold (Au) in model oil compounds (S-free n-dodecane, CH3(CH2)10CH3, DD; and S-bearing 1-dodecanethiol, CH3(CH2)10CH2SH; DDT) from 25 °C to 250 °C using in-situ synchrotron X-ray absorption spectroscopy (XAS) experiments to determine the speciation and the structural properties of gold complexes in the aqueous- and oil-based fluids. For most experiments, DD or DDT were in contact with Au-bearing acidified water, or acidified water plus 10 wt% NaCl (pH25°C = 1.85 in both cases). Gold rapidly partitioned from the aqueous phase into DD and DDT. Below 125 °C, Au(III)Cl is dominant in the DD and the adjacent water with a refined coordination number (CN) of chloride of 4.0(3) and an AuCl bond length of 2.28 Å, consistent with the tetrachloroaurate complex (AuCl4−) being stable in both the aqueous and organic phases. In contrast, Au(III) is rapidly reduced in the presence of DDT and an Au(I) complex dominates in both water and adjacent DDT with a CN of sulfur ∼2.0, suggesting a [RS-Au-SR]− (RS = DDT with deprotonated thiol group) complex with AuS bond lengths ranging from 2.29(1) Å to 2.31(3) Å. In an open system of DDT in contact with water, of which the water and DDT were analyzed separately, AuCl4− was dominant in the water phase, and Au(RS)2− dominant in DDT, possibly due to different equilibration kinetics in the beaker and glassy carbon tube. Since sulfur and organothiol compounds are ubiquitous and abundant components in natural oils, this study demonstrates the potential of natural oils to scavenge and enrich gold from co-existing gold-bearing brines. In particular, Au(I) organothiol complexes may contribute to transport in low-temperature (<125 °C) ore fluids such as those in basinal environments – in both hydrothermal fluids and oils. At temperatures ≥125 °C, gold was reduced to metallic gold in all experiments, suggesting that organo-stabilized nanoparticles may be the major form of gold to be scavenged, concentrated or transported in crude oils at these conditions. The results imply that brine-oil interactions may enrich Au in oils, and that oils may be an effective ore fluid in sedimentary environments.

    Related items

    Showing items related by title, author, creator and subject.

    • Gold transport in hydrothermal fluids: Competition among the Cl-, Br-, HS- and NH3(aq) ligands
      Liu, W.; Etschmann, B.; Testemale, D.; Hazemann, J.; Rempel, Kirsten; Müller, H.; Brugger, J. (2014)
      Since the Au(I) and Au(III) ions are not stable in water, gold transport and deposition in hydrothermal ore fluids are dependent on the identity and stability of the predominant aqueous gold complexes. Gold(I) bisulfide ...
    • Gold remobilisation and formation of high grade ore shoots driven by dissolution-reprecipitation replacement and Ni substitution into auriferous arsenopyrite
      Fougerouse, Denis; Micklethwaite, S.; Tomkins, A.; Mei, Y.; Kilburn, M.; Guagliardo, P.; Fisher, L.; Halfpenny, A.; Gee, M.; Paterson, D.; Howard, D. (2016)
      Both gold-rich sulphides and ultra-high grade native gold oreshoots are common but poorly understood phenomenon in orogenic-type mineral systems, partly because fluids in these systems are considered to have relatively ...
    • Rock-Buffering of Auriferous Fluids in Altered Rocks Associated with the Golden Mile-Style Mineralization, Kalgoorlie Gold Field, Western Australia
      Evans, Katy; Phillips, G.; Powell, R. (2006)
      The Kalgoorlie gold field contains structurally controlled, epigenetic gold deposits hosted by mafic rocks inthe Archean Yilgarn craton of Western Australia. Its giant size has prompted much interest in the processes that ...
    Advanced search

    Browse

    Communities & CollectionsIssue DateAuthorTitleSubjectDocument TypeThis CollectionIssue DateAuthorTitleSubjectDocument Type

    My Account

    Admin

    Statistics

    Most Popular ItemsStatistics by CountryMost Popular Authors

    Follow Curtin

    • 
    • 
    • 
    • 
    • 

    CRICOS Provider Code: 00301JABN: 99 143 842 569TEQSA: PRV12158

    Copyright | Disclaimer | Privacy statement | Accessibility

    Curtin would like to pay respect to the Aboriginal and Torres Strait Islander members of our community by acknowledging the traditional owners of the land on which the Perth campus is located, the Whadjuk people of the Nyungar Nation; and on our Kalgoorlie campus, the Wongutha people of the North-Eastern Goldfields.