Cu isotope fractionation between Cu-bearing phases and hydrothermal fluids: Insights from ex situ and in situ experiments

Dongmei Qi; Chao Zhang; Marina Lazarov

doi:10.2138/am-2023-9155

Article

Cu isotope fractionation between Cu-bearing phases and hydrothermal fluids: Insights from ex situ and in situ experiments

Dongmei Qi , Chao Zhang and Marina Lazarov

Published/Copyright: July 31, 2024

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From the journal American Mineralogist Volume 109 Issue 8

Abstract

Cu isotope ratios have been widely applied to fingerprinting metal sources, tracking fluid pathways, and tracing mineralization processes, for which knowledge of isotope fractionation is required. This paper presents new experimental calibration data of Cu isotope fractionation between Cu-bearing minerals (native Cu and cuprite) and Cl-bearing hydrothermal fluids at 25–800 °C and 0.1–200 MPa. The experiments were performed either using a polytetrafluoroethylene (Teflon) beaker on a hotplate, a rapid heat/rapid quench argon cold seal pressure vessel (RH/RQ Ar-CSPV), or a large volume fluid reactor, which enabled fluid sampling ex situ (the former two) and in situ (the latter). Three setups were designed to investigate Cu isotope fractionation (Δ⁶⁵Cu_{fluid-mineral}): (1) associated with Cu(I) dissolution, Cu(I) disproportionation as well as oxidation of Cu(0) (native copper) and Cu(I) in Cu ± Cu₂O + HCl systems at temperatures of up to 800 °C and pressures of up to 200 MPa; (2) related to Cu-Au alloying processes in the Cu + NaCl/HCl system at 600 °C and 150 MPa; (3) to evaluate the influences of different sampling techniques (ex situ vs. in situ) and superimposed cooling processes. The selected system is Cu₂O + NaCl + 0.2 m HAc/NaAc (pH-buffer), and runs were conducted at 200–250 °C and 20 MPa.

Δ⁶⁵Cu_{fluid-mineral} shows the least variation during solid separation from source fluids, generally <0.16 ± 0.03‰. Positive Δ⁶⁵Cu_{fluid-mineral} values are found in most runs, excluding cuprite dissolution in NaCl/ HCl solutions at 200–250 °C, 20 MPa, and 800 °C, 200 MPa. Cu oxidative leaching into Cu(I) results in decreasing Δ⁶⁵Cu_Cu(I)-Cu(0) values from 0.12 ± 0.05% to 0.07 ± 0.05%, and –0.30 ± 0.03‰ at 25, 50, and 200 °C, respectively. In contrast, Cu dissolution at high temperatures (600–800 °C) leads to Cu(I)-containing quench fluids and subsequent native Cu precipitates. Both products are enriched in heavy isotopes by up to 5‰, caused by preferential enrichment of ⁶⁵Cu at the surface layer during the alloying-induced diffusion transport process. Cuprite oxidative leaching in HCl leads to fluids enriched in Cu(II), and the corresponding Δ⁶⁵Cu_Cu(II)-Cu(I) increases from 0.52 ± 0.04‰ at 25 °C to 0.89 ± 0.02‰ at 50 °C. Fluids are enriched with light isotopes (⁶³Cu) during cuprite dissolution at 200, 250, and 800 °C, i.e., 0–0.55 ± 0.04‰ lower than the precursor. At 250–300 °C, Cu(I) disproportionation into Cu(II) and Cu(0) dominates the observed isotope fractionation, yielding Δ⁶⁵Cu_fluid-Cu₂O up to 0.59 ± 0.03‰ and Δ⁶⁵Cu_Cu(0)-Cu₂O up to –0.28 ± 0.02‰.

Rapid cooling (3–25 K s^–1) relative to slow cooling (0.014 K s^–1) can cause phase separation as well as significant isotope fractionation, particularly if fluids cool from an intermediate high temperature to ambient temperature (e.g., from 200–300 to 25 °C), which highlights the importance of kinetic processes that may potentially alter the isotope composition of natural ore-forming fluids.

Keywords: Cu isotope fractionation; redox reaction; cooling; Cu-Au alloying; diffusion; in situ fluid sampling; Isotopes; Minerals; Petrology: Honoring John Valley

^† Special collection papers can be found online at our website in the Special Collection section.

Funding statement: This research was supported by the National Natural Science Foundation of China (42002059, 41972055), the Natural Science Foundation of Xinjiang Uygur Autonomous Region, China (2020D01C074), Open Project of Key Laboratory, Xinjiang Uygur Autonomous Region, China (2023D04067), the Key Research and Development Program of Xinjiang Uygur Autonomous Region, China (2022B03015-2) and the German Academic Exchange Service (DAAD-57076462).

Acknowledgements

Declaration of competing interest: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References cited

Archibald, S.M., Migdisov, A.A., and Williams-Jones, A.E. (2002) An experimental study of the stability of copper chloride complexes in water vapor at elevated temperatures and pressures. Geochimica et Cosmochimica Acta, 66, 1611–1619.Search in Google Scholar

Asael, D., Matthews, A., Bar-Matthews, M., and Halicz, L. (2007) Copper isotope fractionation in sedimentary copper mineralization (Timna Valley, Israel). Chemical Geology, 243, 238–254, https://doi.org/10.1016/j.chemgeo.2007.06.007.Search in Google Scholar

Asael, D., Matthews, A., Oszczepalski, S., Bar-Matthews, M., and Halicz, L. (2009) Fluid speciation controls of low temperature copper isotope fractionation applied to the Kupferschiefer and Timna ore deposits. Chemical Geology, 262, 147–158, https://doi.org/10.1016/j.chemgeo.2009.01.015.Search in Google Scholar

Asael, D., Matthews, A., Bar-Matthews, M., Harlavan, Y., and Segal, I. (2012) Tracking redox controls and sources of sedimentary mineralization using copper and lead isotopes. Chemical Geology, 310–311, 23–35, https://doi.org/10.1016/j.chemgeo.2012.03.021.Search in Google Scholar

Baggio, S.B., Hartmann, L.A., Lazarov, M., Massonne, H.-J., Opitz, J., Theye, T., and Viefhaus, T. (2018) Origin of native copper in the Paraná volcanic province, Brazil, integrating Cu stable isotopes in a multi-analytical approach. Mineralium Deposita, 53, 417–434.Search in Google Scholar

Berkenbosch, H.A., de Ronde, C.E.J., Paul, B.T., and Gemmell, J.B. (2015) Characteristics of Cu isotopes from chalcopyrite-rich black smoker chimneys at Brothers volcano, Kermadec arc, and Niuatahi volcano, Lau basin. Mineralium Deposita, 50, 811–824, https://doi.org/10.1007/s00126-014-0571-y.Search in Google Scholar

Berndt, J., Holtz, F., and Koepke, J. (2001) Experimental constraints on storage conditions in the chemically zoned phonolitic magma chamber of the Laacher See volcano. Contributions to Mineralogy and Petrology, 140, 469–486, https://doi.org/10.1007/PL00007674.Search in Google Scholar

Berry, A.J., Hack, A.C., Mavrogenes, J.A., Newville, M., and Sutton, S.R. (2006) AXANES study of Cu speciation in high-temperature brines using synthetic fluid inclusions. American Mineralogist, 91, 1773–1782, https://doi.org/10.2138/am.2006.1940.Search in Google Scholar

Bornhorst, T.J. and Mathur, R. (2017) Copper isotope constraints on the genesis of the Keweenaw Peninsula Native Copper District, Michigan, USA. Minerals, 7, 185, https://doi.org/10.3390/min7100185.Search in Google Scholar

Brugger, J., McPhail, D.C., Black, J., and Spiccia, L. (2001) Complexation of metal ions in brines: Application of electronic spectroscopy in the study of the Cu(II)-LiCl-H₂O system between 25 and 90 °C. Geochimica et Cosmochimica Acta, 65, 2691–2708, https://doi.org/10.1016/S0016-7037(01)00614-7.Search in Google Scholar

Brugger, J., Etschmann, B., Liu, W., Testemale, D., Hazemann, J.L., Emerich, H., Van Beek, W., and Proux, O. (2007) An XAS study of the structure and thermodynamics of Cu(I) chloride complexes in brines up to high temperature (400 °C, 600 bar). Geochimica et Cosmochimica Acta, 71, 4920–4941.Search in Google Scholar

Brzozowski, M.J., Good, D.J., Wu, C., and Li, W. (2021) Cu isotope systematics of conduit-type Cu-PGE mineralization in the Eastern Gabbro, Coldwell Complex, Canada. Mineralium Deposita, 56, 707–724, https://doi.org/10.1007/s00126-020-00992-8.Search in Google Scholar

Busigny, V., Chen, J., Philippot, P., Borensztajn, S., and Moynier, F. (2018) Insight into hydrothermal and subduction processes from copper and nitrogen isotopes in oceanic metagabbros. Earth and Planetary Science Letters, 498, 54–64, https://doi.org/10.1016/j.epsl.2018.06.030.Search in Google Scholar

Chaudhari, A., Brugger, J., Ram, R., Chowdhury, P., Etschmann, B., Guagliardo, P., Xia, F., Pring, A., Gervinskas, G., Liu, A., and others. (2022) Synchronous solid-state diffusion, dissolution-reprecipitation, and recrystallization leading to isotopic resetting: insights from chalcopyrite replacement by copper sulfides. Geochimica et Cosmochimica Acta, 331, 48–68.Search in Google Scholar

Collings, M.D., Sherman, D.M., and Ragnarsdottir, K.V. (2000) Complexation of Cu²⁺ in oxidized NaCl brines from 25 °C to 175 °C: Results from in situ EXAFS spectroscopy. Chemical Geology, 167, 65–73, https://doi.org/10.1016/S0009-2541(99)00200-4.Search in Google Scholar

Crerar, D.A. and Barnes, H.L. (1976) Ore solution chemistry; V, Solubilities of chalcopyrite and chalcocite assemblages in hydrothermal solution at 200 degrees to 350 degrees C. Economic Geology, 71,772–794, https://doi.org/10.2113/gsecongeo.71.4.772.Search in Google Scholar

D’Angelo, P., Bottari, E., Festa, M.R., Nolting, H.F., and Pavel, N.V. (1997) Structural investigation of copper(II) chloride solutions using X-ray absorption spectroscopy. The Journal of Chemical Physics, 107, 2807–2812, https://doi.org/10.1063/1.474638.Search in Google Scholar

Dekov, VM., Rouxel, O., Asael, D., Hålenius, U., and Munnik, F (2013) Native Cu from the oceanic crust: Isotopic insights into native metal origin. Chemical Geology, 359, 136–149, https://doi.org/10.1016/j.chemgeo.2013.10.001.Search in Google Scholar

Dick, J.M. (2019) CHNOSZ: Thermodynamic calculations and diagrams for geochemistry. Frontiers of Earth Science, 7, 1–18.Search in Google Scholar

Dickson, F.W., Blount, C., and Tunell, G. (1963) Use of hydrothermal solution equipment to determine the solubility of anhydrite in water from 100 degrees C to 275 degrees C and from 1 bar to 1000 bars pressure. American Journal of Science, 261, 61–78, https://doi.org/10.2475/ajs.261.1.61.Search in Google Scholar

Duan, J., Tang, J., Li, Y., Liu, S.-A., Wang, Q., Yang, C., and Wang, Y. (2016) Copper isotopic signature of the Tiegelongnan high-sulfidation copper deposit, Tibet: Implications for its origin and mineral exploration. Mineralium Deposita, 51, 591–602, https://doi.org/10.1007/s00126-015-0624-x.Search in Google Scholar

Ehrlich, S., Butler, I., Halicz, L., Rickard, D., Oldroyd, A., and Matthews, A. (2004) Experimental study of the copper isotope fractionation between aqueous Cu(II) and covellite, CuS. Chemical Geology, 209, 259–269, https://doi.org/10.1016/j.chemgeo.2004.06.010.Search in Google Scholar

Eslami, A., Malvoisin, B., Grieco, G., Aradi, L.E., Marchesi, C., Cavallo, A., Montanini, A., Borghini, G., Mathur, R., Ikehata, K., and others. (2021) Native copper formation associated with serpentinization in the Cheshmeh-Bid ophiolite massif (Southern Iran). Lithos, 382–383, 105953, https://doi.org/10.1016/j.lithos.2020.105953.Search in Google Scholar

Fernandez, A. and Borrok, D.M. (2009) Fractionation of Cu, Fe, and Zn isotopes during the oxidative weathering of sulfide-rich rocks. Chemical Geology, 264, 1–12, https://doi.org/10.1016/j.chemgeo.2009.01.024.Search in Google Scholar

Fujii, T., Moynier, F., Abe, M., Nemoto, K., and Albarède, F (2013) Copper isotope fractionation between aqueous compounds relevant to low temperature geochemistry and biology. Geochimica et Cosmochimica Acta, 110, 29–44, https://doi.org/10.1016/j.gca.2013.02.007.Search in Google Scholar

Fujii, T., Moynier, F., Blichert-Toft, J., and Albarède, F. (2014) Density functional theory estimation of isotope fractionation of Fe, Ni, Cu, and Zn among species relevant to geochemical and biological environments. Geochimica et Cosmochimica Acta, 140, 553–576, https://doi.org/10.1016/j.gca.2014.05.051.Search in Google Scholar

Fulton, J.L., Hoffmann, M.M., and Darab, J.G. (2000a) An X-ray absorption fine structure study of copper(I) chloride coordination structure in water up to 325 °C. Chemical Physics Letters, 330, 300–308, https://doi.org/10.1016/S0009-2614(00)01110-6.Search in Google Scholar

Fulton, J.L., Hoffmann, M.M., Darab, J.G., Palmer, B.J., and Stern, E.A. (2000b) Copper(I) and Copper(II) coordination structure under hydrothermal conditions at 325 °C: An X-ray absorption fine structure and molecular dynamics study. The Journal of Physical Chemistry A, 104, 11651–11663, https://doi.org/10.1021/jp001949a.Search in Google Scholar

Gregory, M.J. and Mathur, R. (2017) Understanding copper isotope behavior in the high temperature magmatic-hydrothermal porphyry environment. Geochemistry, Geophysics, Geosystems, 18, 4000–4015, https://doi.org/10.1002/2017GC007026.Search in Google Scholar

Guo, H., Xia, Y., Bai, R., Zhang, X., and Huang, F. (2020) Experiments on Cuisotope fractionation between chlorine-bearing fluid and silicate magma: Implications for fluid exsolution and porphyry Cu deposits. National Science Review, 7, 1319–1330, https://doi.org/10.1093/nsr/nwz221.Search in Google Scholar

Hack, A.C. and Mavrogenes, J.A. (2006) A cold-sealing capsule design for synthesis of fluid inclusions and other hydrothermal experiments in a piston-cylinder apparatus. American Mineralogist, 91, 203–210, https://doi.org/10.2138/am.2006.1898.Search in Google Scholar

Hannington, M.D., Thompson, G., Rona, P.A., and Scott, S.D. (1988) Gold and native copper in supergene sulphides from the Mid-Atlantic Ridge. Nature, 333, 64–66.Search in Google Scholar

Hezarkhani, A. and Williams-Jones, A.E. (1998) Controls of alteration and mineralization in the Sungun porphyry copper deposit, Iran: Evidence from fluid inclusions and stable isotopes. Economic Geology, 93, 651–670.Search in Google Scholar

Huang, J., Liu, S.A., Gao, Y., Xiao, Y., and Chen, S. (2016a) Copper and zinc isotope systematics of altered oceanic crust at IODP Site 1256 in the eastern equatorial Pacific. Journal of Geophysical Research: Solid Earth, 121, 7086–7100, https://doi.org/10.1002/2016JB013095.Search in Google Scholar

Huang, J., Liu, S.-A., Wörner, G., Yu, H., and Xiao, Y (2016b) Copper isotope behavior during extreme magma differentiation and degassing: A case study on Laacher See phonolite tephra (East Eifel, Germany). Contributions to Mineralogy and Petrology, 171, 76, https://doi.org/10.1007/s00410-016-1282-4.Search in Google Scholar

Huang, J., Huang, F., Wang, Z., Zhang, X., and Yu, H. (2017) Copper isotope fractionation during partial melting and melt percolation in the upper mantle: Evidence from massif peridotites in Ivrea-Verbano Zone, Italian Alps. Geochimica et Cosmochimica Acta, 211, 48–63, https://doi.org/10.1016/j.gca.2017.05.007.Search in Google Scholar

Huebner, J.S. and Sato, M. (1970) The oxygen fugacity-temperature relationships of manganese oxide and nickel oxide buffers. American Mineralogist, 55, 934–952.Search in Google Scholar

Ijichi, Y., Ohno, T., and Sakata, S. (2018) Copper isotopic fractionation during adsorption on manganese oxide: Effects of pH and desorption. Geochemical Journal, 52, e1–e6, https://doi.org/10.2343/geochemj.2.0516.Search in Google Scholar

Ikehata, K. and Hirata, T. (2012) Copper isotope characteristics of copper-rich minerals from the Horoman Peridotite Complex, Hokkaido, Northern Japan. Economic Geology and the Bulletin of the Society of Economic Geologists, 107, 1489–1497, https://doi.org/10.2113/econgeo.107.7.1489.Search in Google Scholar

Ikehata, K., Notsu, K., and Hirata, T. (2011) Copper isotope characteristics of copper-rich minerals from besshi-type volcanogenic massive sulfide deposits, Japan, determined using a femtosecond LA-MC-ICP-MS. Economic Geology and the Bulletin of the Society of Economic Geologists, 106, 307–316, https://doi.org/10.2113/econgeo.106.2.307.Search in Google Scholar

Jähne, B., Heinz, G., and Dietrich, W. (1987) Measurement of the diffusion coefficients of sparingly soluble gases in water. Journal of Geophysical Research: Oceans, 92, 10767–10776.Search in Google Scholar

Johnson, J.W., Oelkers, E.H., and Helgeson, H.C. (1992) SUPCRT92: A software package for calculating the standard molal thermodynamic properties of minerals, gases, aqueous species, and reactions from 1 to 5000 bar and 0 to 1000 °C. Computers & Geosciences, 18, 899–947, https://doi.org/10.1016/0098-3004(92)90029-Q.Search in Google Scholar

Kharaka, Y.K., Carothers, W.W., and Rosenbauer, R.J. (1983) Thermal decarboxylation of acetic acid: Implications for origin of natural gas. Geochimica et Cosmochimica Acta, 47, 397–402, https://doi.org/10.1016/0016-7037(83)90262-4.Search in Google Scholar

Kidder, J.A., Voinot, A., Leybourne, M.I., Layton-Matthews, D., and Bowell, R.J. (2021) Using stable isotopes of Cu, Mo, S, and ⁸⁷Sr/⁸⁶Sr in hydrogeochemical mineral exploration as tracers of porphyry and exotic copper deposits. Applied Geochemistry, 128, 104935, https://doi.org/10.1016/j.apgeochem.2021.104935.Search in Google Scholar

Kim, Y., Lee, I., Oyungerel, S., Jargal, L., and Tsedenbal, T. (2019) Cu and S isotopic signatures of the Erdenetiin Ovoo porphyry Cu-Mo deposit, northern Mongolia: Implications for their origin and mineral exploration. Ore Geology Reviews, 104, 656–669, https://doi.org/10.1016/j.oregeorev.2018.11.025.Search in Google Scholar

Kimball, B.E., Mathur, R., Dohnalkova, A.C., Wall, A.J., Runkel, R.L., and Brantley, S.L. (2009) Copper isotope fractionation in acid mine drainage. Geochimica et Cosmochimica Acta, 73, 1247–1263, https://doi.org/10.1016/j.gca.2008.11.035.Search in Google Scholar

Kuper, A., Letaw, H. Jr., Slifkin, L., Sonder, E., and Tomizuka, C. (1954) Self-diffusion in copper. Physical Review, 96, 1224–1225, https://doi.org/10.1103/PhysRev.96.1224.Search in Google Scholar

Larson, P.B., Maher, K., Ramos, F.C., Chang, Z., Gaspar, M., and Meinert, L.D. (2003) Copper isotope ratios in magmatic and hydrothermal ore-forming environments. Chemical Geology, 201, 337–350, https://doi.org/10.1016/j.chemgeo.2003.08.006.Search in Google Scholar

Lazarov, M. and Horn, I. (2015) Matrix and energy effects during in-situ determination of Cu isotope ratios by ultraviolet-femtosecond laser ablation multicollector inductively coupled plasma mass spectrometry. Spectrochimica Acta Part B, Atomic Spectroscopy, 111, 64–73, https://doi.org/10.1016/j.sab.2015.06.013.Search in Google Scholar

Li, D. and Liu, S-A. (2022) Copper isotope fractionation during basalt leaching at 25 °C and pH = 0.3, 2. Journal of Earth Science, 33, 82–91, https://doi.org/10.1007/s12583-021-1499-7.Search in Google Scholar

Li, W., Jackson, S.E., Pearson, N.J., and Graham, S. (2010) Copper isotopic zonation in the Northparkes porphyry Cu-Au deposit, SE Australia. Geochimica et Cosmochimica Acta, 74, 4078–4096, https://doi.org/10.1016/j.gca.2010.04.003.Search in Google Scholar

Lide, R.D. (2010) CRC Handbook of Chemistry and Physics 90th Edition, 2804 p. CRC Press.Search in Google Scholar

Liu, W., McPhail, D.C., and Brugger, J. (2001) An experimental study of copper(I)-chloride and copper(I)-acetate complexing in hydrothermal solutions between 50 °C and 250 °C and vapor-saturated pressure. Geochimica et Cosmochimica Acta, 65, 2937–2948, https://doi.org/10.1016/S0016-7037(01)00631-7.Search in Google Scholar

Liu, S.A., Liu, P.P., Lv, Y., Wang, Z.Z., and Dai, J.G. (2019) Cu and Zn isotope fractionation during oceanic alteration: Implications for Oceanic Cu and Zn cycles. Geochimica et Cosmochimica Acta, 257, 191–205, https://doi.org/10.1016/j.gca.2019.04.026.Search in Google Scholar

Liu, S., Li, Y., Liu, J., Yang, Z., Liu, J., and Shi, Y. (2021) Equilibrium Cu isotope fractionation in copper minerals: A first-principles study. Chemical Geology, 564, 120060, https://doi.org/10.1016/j.chemgeo.2021.120060.Search in Google Scholar

Luczaj, J. and Huang, H. (2018) Copper and sulfur isotope ratios in Paleozoichosted Mississippi Valley-type mineralization in Wisconsin, USA. Applied Geochemistry, 89, 173–179, https://doi.org/10.1016/j.apgeochem.2017.12.013.Search in Google Scholar

Macdonald, D., Shierman, G., and Butler, P (1972) Thermodynamics of metal–water systems at elevated temperatures. Part 1. The water and copper-water systems. U.S. Department of Energy, Office of Scientific and Technical Information, Technical Report, NSA-27-022874.Search in Google Scholar

Maher, K.C. and Larson, P.B. (2007) Variation in copper isotope ratios and controls on fractionation in hypogene skarn mineralization at Coroccohuayco and Tintaya, Perú. Economic Geology and the Bulletin of the Society of Economic Geologists, 102, 225–237, https://doi.org/10.2113/gsecongeo.102.2.225.Search in Google Scholar

Maher, K.C., Jackson, S., and Mountain, B. (2011) Experimental evaluation of the fluid-mineral fractionation of Cu isotopes at 250 °C and 300 °C. Chemical Geology, 286, 229–239.Search in Google Scholar

Majima, H., Awakura, Y., Enami, K., Ueshima, H., and Hirato, T. (1989) Kinetic study of the dissolution of cuprite in oxyacid solutions. Metallurgical Transactions B: Process Metallurgy, 20, 573–580, https://doi.org/10.1007/BF02655914.Search in Google Scholar

Maréchal, C.N., Télouk, P., and Albarède, F. (1999) Precise analysis of copper and zinc isotopic compositions by plasma-source mass spectrometry. Chemical Geology, 156, 251–273, https://doi.org/10.1016/S0009-2541(98)00191-0.Search in Google Scholar

Markl, G., Lahaye, Y., and Schwinn, G. (2006) Copper isotopes as monitors of redox processes in hydrothermal mineralization. Geochimica et Cosmochimica Acta, 70, 4215–4228, https://doi.org/10.1016/j.gca.2006.06.1369.Search in Google Scholar

Mason, T.F.D., Weiss, D.J., Chapman, J.B., Wilkinson, J.J., Tessalina, S.G., Spiro, B., Horstwood, M.S.A., Spratt, J., and Coles, B.J. (2005) Zn and Cu isotopic variability in the Alexandrinka volcanic-hosted massive sulphide (VHMS) ore deposit, Urals, Russia. Chemical Geology, 221, 170–187, https://doi.org/10.1016/j.chemgeo.2005.04.011.Search in Google Scholar

Mathur, R., Ruiz, J., Titley, S., Liermann, L., Buss, H., and Brantley, S. (2005) Cu isotopic fractionation in the supergene environment with and without bacteria. Geochimica et Cosmochimica Acta, 69, 5233–5246, https://doi.org/10.1016/j.gca.2005.06.022.Search in Google Scholar

Mathur, R., Titley, S., Barra, F., Brantley, S., Wilson, M., Phillips, A., Munizaga, F., Maksaev, V., Vervoort, J., and Hart, G. (2009) Exploration potential of Cu isotope fractionation in porphyry copper deposits. Journal of Geochemical Exploration, 102, 1–6, https://doi.org/10.1016/j.gexplo.2008.09.004.Search in Google Scholar

Mathur, R., Dendas, M., Titley, S., and Phillips, A. (2010) Patterns in the copper isotope composition of minerals in porphyry copper deposits in Southwestern United States. Economic Geology and the Bulletin of the Society of Economic Geologists, 105, 1457–1467, https://doi.org/10.2113/econgeo.105.8.1457.Search in Google Scholar

Matthews, W., Linnen, R.L., and Guo, Q. (2003) A filler-rod technique for controlling redox conditions in cold-seal pressure vessels. American Mineralogist, 88, 701–707.Search in Google Scholar

Mattsson, E. and Bockris, J.O.M. (1959) Galvanostatic studies of the kinetics of deposition and dissolution in the copper + copper sulphate system. Transactions of the Faraday Society, 55, 1586–1601, https://doi.org/10.1039/tf9595501586.Search in Google Scholar

May, T.W. and Wiedmeyer, R.H. (1998) A table of polyatomic interferences in ICP-MS isotope abundance interference. Atomic Spectroscopy, 19, 150–155.Search in Google Scholar

McLaughlin, E. (1960) Transport coefficient ratios for isotopically substituted molecules in the liquid phase and the transport mechanism. Physica, 26, 650–652, https://doi.org/10.1016/0031-8914(60)90130-0.Search in Google Scholar

Mei, Y., Liu, W., Sherman, D.M., and Brugger, J. (2014) Metal complexation and ion hydration in low density hydrothermal fluids: Ab initio molecular dynamics simulation of Cu(I) and Au(I) in chloride solutions (25–1000 °C, 1–5000 bar). Geochimica et Cosmochimica Acta, 131, 196–212, https://doi.org/10.1016/j.gca.2014.01.033.Search in Google Scholar

Mirnejad, H., Mathur, R., Einali, M., Dendas, M., and Alirezaei, S. (2010) A comparative copper isotope study of porphyry copper deposits in Iran. Geochemistry Exploration Environment Analysis, 10, 413–418, https://doi.org/10.1144/1467-7873/09-229.Search in Google Scholar

Molnár, F., Mänttäri, I., O’Brien, H., Lahaye, Y, Pakkanen, L., Johanson, B., Käpyaho, A., Sorjonen-Ward, P, Whitehouse, M., and Sakellaris, G. (2016) Boron, sulphur and copper isotope systematics in the orogenic gold deposits of the Archaean Hattu schist belt, eastern Finland. Ore Geology Reviews, 77, 133–162, https://doi.org/10.1016/j.oregeorev.2016.02.012.Search in Google Scholar

Mountain, B.W. and Seward, T.M. (1999) The hydrosulphide/sulphide complexes of copper(I): Experimental determination of stoichiometry and stability at 22 °C and reassessment of high temperature data. Geochimica et Cosmochimica Acta, 63, 11–29, https://doi.org/10.1016/S0016-7037(98)00288-9.Search in Google Scholar

Mountain, B.W. and Seward, T.M. (2003) Hydrosulfide/sulfide complexes of copper(I): Experimental confirmation of the stoichiometry and stability of Cu(HS)2− to elevated temperatures. Geochimica et Cosmochimica Acta, 67, 3005–3014, https://doi.org/10.1016/S0016-7037(03)00303-X.Search in Google Scholar

Ni, P., Macris, C.A., Darling, E.A., and Shahar, A. (2021) Evaporation-induced copper isotope fractionation: Insights from laser levitation experiments. Geochimica et Cosmochimica Acta, 298, 131–148, https://doi.org/10.1016/j.gca.2021.02.007.Search in Google Scholar

Nikitenkov, N.N., Kolokolov, D.Yu., Chernov, I.P., and Tyurin, Yu.I. (2006) SIMS investigations of isotope effects at a processed solid surface. Vacuum, 81, 202–210, https://doi.org/10.1016/j.vacuum.2006.03.013.Search in Google Scholar

Okamoto, H., Chakrabarti, D., Laughlin, D., and Massalski, T. (1987) The Au-Cu (gold-copper) system. Journal of Phase Equilibria, 8, 454–474, https://doi.org/10.1007/BF02893155.Search in Google Scholar

Palmer, D.A. and Drummond, S.E. (1986) Thermal decarboxylation of acetate. Part I. The kinetics and mechanism of reaction in aqueous solution. Geochimica et Cosmochimica Acta, 50, 813–823, https://doi.org/10.1016/0016-7037(86)90357-1.Search in Google Scholar

Park, I., Yoo, K., Alorro, R.D., Kim, M., and Kim, S. (2017) Leaching of copper from cuprous oxide in aerated sulfuric acid. Materials Transactions, 58, 1500–1504, https://doi.org/10.2320/matertrans.M2017147.Search in Google Scholar

Pękala, M., Asael, D., Butler, I.B., Matthews, A., and Rickard, D. (2011) Experimental study of Cu isotope fractionation during the reaction of aqueous Cu(II) with Fe(II) sulphides at temperatures between 40 and 200 °C. Chemical Geology, 289, 31–38, https://doi.org/10.1016/j.chemgeo.2011.07.004.Search in Google Scholar

Pouchou, J.-L. and Pichoir, F. (1991) Quantitative analysis of homogeneous or stratified microvolumes applying the model “PAP”. In K.F.J. Heinrich and D.E. Newbury, Eds., Electron Probe Quantitation, 31–75. Springer.Search in Google Scholar

Qi, D. (2019) Isotopic and elemental distribution of copper between Cu-bearing minerals and aqueous fluids: implications of an experimental study, 153 p. Ph.D. thesis, Leibniz University of Hannover.Search in Google Scholar

Qi, D., Behrens, H., Lazarov, M., and Weyer, S. (2019) Cu isotope fractionation during reduction processes in aqueous systems: Evidences from electrochemical deposition. Contributions to Mineralogy and Petrology, 174, 37, https://doi.org/10.1007/s00410-019-1568-4.Search in Google Scholar

Qi, D., Behrens, H., Botcharnikov, R., Derrey, I., Holtz, F., Zhang, C., Li, X., and Horn, I. (2020) Reaction between Cu-bearing minerals and hydrothermal fluids at 800 °C and 200 MPa: Constraints from synthetic fluid inclusions. American Mineralogist, 105, 1126–1139, https://doi.org/10.2138/am-2020-7114.Search in Google Scholar

Qi, D., Behrens, H., Lazarov, M., Botcharnikov, R., Zhang, C., Ostertag-Henning, C., and Weyer, S. (2024) Experimental study on the reaction of cuprite (Cu₂O) with acetate-bearing hydrothermal fluids at 100–250 °C and 5–30 MPa. ACS Earth and Space Chemistry, 8, 499–519.Search in Google Scholar

Ravi, R. and Paul, A. (2012) Diffusion mechanism in the gold-copper system. Journal of Materials Science Materials in Electronics, 23, 2152–2156, https://doi.org/10.1007/s10854-012-0729-2.Search in Google Scholar

Rempel, K.U., Liebscher, A., Meixner, A., Romer, R.L., and Heinrich, W. (2012) An experimental study of the elemental and isotopic fractionation of copper between aqueous vapour and liquid to 450 °C and 400 bar in the CuCl-NaCl-H₂O and CuCl-NaHS-NaCl-H₂O systems. Geochimica et Cosmochimica Acta, 94, 199–216, https://doi.org/10.1016/j.gca.2012.06.028.Search in Google Scholar

Ripley, E.M., Dong, S., Li, C., and Wasylenki, L.E. (2015) Cu isotope variations between conduit and sheet-style Ni-Cu-PGE sulfide mineralization in the Midcontinent Rift System, North America. Chemical Geology, 414, 59–68, https://doi.org/10.1016/j.chemgeo.2015.09.007.Search in Google Scholar

Robie, R.A. and Hemingway, B.S. (1995) Thermodynamic properties of minerals and related substances at 298.15 K and 1 bar (10⁵ pascals) pressure and at higher temperatures, 461 p. U.S. Geological Survey Bulletin 2131.Search in Google Scholar

Roebbert, Y., Rabe, K., Lazarov, M., Schuth, S., Schippers, A., Dold, B., and Weyer, S. (2018) Fractionation of Fe and Cu isotopes in acid mine tailings: Modification and application of a sequential extraction method. Chemical Geology, 493, 67–79, https://doi.org/10.1016/j.chemgeo.2018.05.026.Search in Google Scholar

Roedder, E. (1984) Fluid Inclusions, 646 p. Reviews in Mineralogy and Geochemistry Vol. 12.Search in Google Scholar

Rouxel, O., Fouquet, Y., and Ludden, J.N. (2004) Copper isotope systematics of the Lucky Strike, Rainbow, and Logatchev sea-floor hydrothermal fields on the Mid-Atlantic Ridge. Economic Geology and the Bulletin of the Society of Economic Geologists, 99, 585–600, https://doi.org/10.2113/gsecongeo.99.3.585.Search in Google Scholar

Savage, P.S., Moynier, F., Chen, H., Shofner, G., Siebert, J., Badro, J., and Puchtel, I.S. (2015) Copper isotope evidence for large-scale sulphide fractionation during Earth’s differentiation. Geochemical Perspectives Letters, 1, 53–64, https://doi.org/10.7185/geochemlet.1506.Search in Google Scholar

Schauble, E.A. (2004) Applying stable isotope fractionation theory to new systems. Reviews in Mineralogy and Geochemistry, 55, 65–111, https://doi.org/10.2138/gsrmg.55.1.65.Search in Google Scholar

Schmidt, C., Watenphul, A., Jahn, S., Schapan, I., Scholten, L., Newville, M.G., and Lanzirotti, A. (2018) Copper complexation and solubility in high-temperature hydrothermal fluids: A combined study by Raman, X-ray fluorescence, and X-ray absorption spectroscopies and ab initio molecular dynamics simulations. Chemical Geology, 494, 69–79, https://doi.org/10.1016/j.chemgeo.2018.07.018.Search in Google Scholar

Seo, J.H., Lee, S.K., and Lee, I. (2007) Quantum chemical calculations of equilibrium copper (I) isotope fractionations in ore-forming fluids. Chemical Geology, 243, 225–237, https://doi.org/10.1016/j.chemgeo.2007.05.025.Search in Google Scholar

Seyfried, W.E., Gordon, P.C., and Dickson, F.W. (1979) A new reaction cell for hydrothermal solution equipment. American Mineralogist, 64, 646–649.Search in Google Scholar

Sherman, D.M. (2013) Equilibrium isotopic fractionation of copper during oxidation/reduction, aqueous complexation and ore-forming processes: Predictions from hybrid density functional theory. Geochimica et Cosmochimica Acta, 118, 85–97, https://doi.org/10.1016/j.gca.2013.04.030.Search in Google Scholar

Sherman, D.M. and Little, S.H. (2020) Isotopic disequilibrium of Cu in marine ferromanganese crusts: Evidence from ab initio predictions of Cu isotope fractionation on sorption to birnessite. Earth and Planetary Science Letters, 549, 116540, https://doi.org/10.1016/j.epsl.2020.116540.Search in Google Scholar

Syverson, D.D., Borrok, D.M., Niebuhr, S., and Seyfried, W.E. Jr. (2021) Chalcopyrite-dissolved Cu isotope exchange at hydrothermal conditions: Experimental constraints at 350 °C and 50 MPa. Geochimica et Cosmochimica Acta, 298, 191–206, https://doi.org/10.1016/j.gca.2021.02.005.Search in Google Scholar

Tompkins, H.G. and Pinnel, M.R. (1976) Low-temperature diffusion of copper through gold. Journal of Applied Physics, 47, 3804–3812, https://doi.org/10.1063/1.323265.Search in Google Scholar

Ulrich, T., Günther, D., and Heinrich, C.A. (1999) Gold concentrations of magmatic brines and the metal budget of porphyry copper deposits. Nature, 399, 676–679, https://doi.org/10.1038/21406.Search in Google Scholar

Wadsworth, M.E. and Wadia, D.R. (1955) Reaction rate study of the dissolution of cuprite in sulphuric acid. Journal of the Minerals Metals & Materials Society, 7, 755–759, https://doi.org/10.1007/BF03377565.Search in Google Scholar

Wang, P., Dong, G., Santosh, M., Liu, K., and Li, X. (2017) Copper isotopes trace the evolution of skarn ores: A case study from the Hongshan-Hongniu Cu deposit, southwest China. Ore Geology Reviews, 88, 822–831, https://doi.org/10.1016/j.oregeorev.2016.11.023.Search in Google Scholar

Wang, C., Bagas, L., Chen, J., Yang, L., Zhang, D., Du, B., and Shi, K. (2018) The genesis of the Liancheng Cu-Mo deposit in the Lanping Basin of SW China: Constraints from geology, fluid inclusions, and Cu-S-H-O isotopes. Ore Geology Reviews, 92, 113–128, https://doi.org/10.1016/j.oregeorev.2017.11.012.Search in Google Scholar

Wu, L., Hu, R., Li, X., Liu, S., Tang, Y.-W., and Tang, Y.-Y. (2017) Copper isotopic compositions of the Zijinshan high-sulfidation epithermal Cu-Au deposit, South China: Implications for deposit origin. Ore Geology Reviews, 83, 191–199, https://doi.org/10.1016/j.oregeorev.2016.12.013.Search in Google Scholar

Xiao, Z., Gammons, C.H., and Williams-Jones, A.E. (1998) Experimental study of copper(I) chloride complexing in hydrothermal solutions at 40 to 300 °C and saturated water vapor pressure. Geochimica et Cosmochimica Acta, 62, 2949–2964, https://doi.org/10.1016/S0016-7037(98)00228-2.Search in Google Scholar

Yao, J., Mathur, R., Sun, W., Song, W., Chen, H., Mutti, L., Xiang, X., and Luo, X. (2016) Fractionation of Cu and Mo isotopes caused by vapor-liquid partitioning, evidence from the Dahutang W-Cu-Mo ore field. Geochemistry, Geophysics, Geosystems, 17, 1725–1739, https://doi.org/10.1002/2016GC006328.Search in Google Scholar

Zajacz, Z., Seo, J.H., Candela, P.A., Piccoli, P.M., and Tossell, J.A. (2011) The solubility of copper in high-temperature magmatic vapors: A quest for the significance of various chloride and sulfide complexes. Geochimica et Cosmochimica Acta, 75, 2811–2827, https://doi.org/10.1016/j.gca.2011.02.029.Search in Google Scholar

Zegkinoglou, N.N., Mathur, R., Kilias, S.P., Godfrey, L., Pletsas, V., Nomikou, P., and Zaronikola, N. (2023) Boiling-induced extreme Cu isotope fractionation in sulfide minerals forming by active hydrothermal diffusers at the Aegean Kolumbo volcano: Evidence from in situ isotope analysis. Geology, 51, 1072–1076, https:ZZdoi.org/10.!130/G51404.1.Search in Google Scholar

Zeng, Z., Li, X., Chen, S., de Jong, J., Mattielli, N., Qi, H., Pearce, C., and Murton, B.J. (2021) Iron, copper, and zinc isotopic fractionation in seafloor basalts and hydrothermal sulfides. Marine Geology, 436, 106491, https://doi.org/10.1016/j.margeo.2021.106491.Search in Google Scholar

Zhang, Z., Mao, J., Wang, F., and Pirajno, F. (2006) Native gold and native copper grains enclosed by olivine phenocrysts in a picrite lava of the Emeishan large igneous province, SW China. American Mineralogist, 91, 1178–1183, https://doi.org/10.2138/am.2006.1888.Search in Google Scholar

Zhao, Y., Xue, C., Liu, S.A., Symons, D.T.A., Zhao, X., Yang, Y., and Ke, J. (2017) Copper isotope fractionation during sulfide-magma differentiation in the Tulaergen magmatic Ni-Cu deposit, NW China. Lithos, 286–287, 206–215, https://doi.org/10.1016/j.lithos.2017.06.007.Search in Google Scholar

Zhao, Y., Xue, C., Liu, S.A., Mathur, R., Symons, D.T., Ke, J., Zhao, X.B., Seltmann, R., Jiao, J.G., Huang, Y.S., and others. (2024) Vapor-phases as Cu transport agents for the shear-zone-hosted mineralization system: A perspective from H-O-S-Cu isotope. American Mineralogist, 109, 667–681, https://doi.org/10.2138/am-2022-8888.Search in Google Scholar

Zheng, Y.C., Liu, S.A., Wu, C.D., Griffin, W.L., Li, Z.Q., Xu, B., Yang, Z.M., Hou, Z.Q., and O’Reilly, S.Y. (2019) Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting. Geology, 47, 135–138, https://doi.org/10.1130/G45362.1.Search in Google Scholar

Zhu, X.K., O’Nions, R.K., Guo, Y., Belshaw, N.S., and Rickard, D. (2000) Determination of natural Cu-isotope variation by plasma-source mass spectrometry: Implications for use as geochemical tracers. Chemical Geology, 163, 139–149, https://doi.org/10.1016/S0009-2541(99)00076-5.Search in Google Scholar

Zhu, X.K., Guo, Y., Williams, R.J.P., O’Nions, R.K., Matthews, A., Belshaw, N.S., Canters, G.W., de Waal, E.C., Weser, U., Burgess, B.K., and others. (2002) Mass fractionation processes of transition metal isotopes. Earth and Planetary Science Letters, 200, 47–62, https://doi.org/10.1016/S0012-821X(02)00615-5.Search in Google Scholar

Received: 2023-08-14

Accepted: 2023-11-02

Published Online: 2024-07-31

Published in Print: 2024-08-27

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https://doi.org/10.2138/am-2023-9155

Keywords for this article

Cu isotope fractionation; redox reaction; cooling; Cu-Au alloying; diffusion; in situ fluid sampling; Isotopes; Minerals; Petrology: Honoring John Valley