Mineralium Deposita

, 44:647 | Cite as

Selenium and sulfur concentrations in the Bushveld Complex of South Africa and implications for formation of the platinum-group element deposits

  • Sarah-Jane BarnesEmail author
  • Dany Savard
  • L. Paul Bédard
  • Wolfgang D. Maier


We have determined the S, Se, Cu and La contents through a complete stratigraphic section of the Bushveld Complex. The principle aim was to determine which phases controlled these elements. S, Se and Cu show positive correlations, but these elements do not correlate with La. In most cases, the concentration of S, Se and Cu in rocks containing greater than 800 ppm S can be modeled by segregation of a Fe–Ni–Cu sulfide liquid from a fractionating magma. As the magma evolved, Se and Cu were depleted by the continual segregation of sulfide liquid and the S/Se and S/Cu of the rocks increased. The Se/Cu ratio is higher in the more evolved rocks, which suggests that Se has a slightly lower partition coefficient than Cu into sulfide liquid (1,200 versus 1,700). The Lower and lower Critical Zone of the complex contains on average only 99 ppm S. The low S content of these rocks has led some authors to suggest that these rocks do not contain cumulate sulfides, despite the fact that they are moderately enriched in PGE. These samples fall along the same trend as the S-rich samples on the S-versus-Se plot and the S/La and Se/La ratios are greater than the initial magmas suggesting that despite the low S contents cumulate sulfides are present. Three models may be suggested in order to explain the low S content in the Lower and Critical Zone rocks: (a) the sulfides that were present have migrated away from the cumulate pile into the footwall or center of the intrusion; (b) the magma was saturated in sulfides at depth and during transport some sulfides lagged in embayments; (c) the rocks have lost both S and Se at high temperature. The first two models have important implications for exploration.


Selenium Sulfur Platinum-group elements Merensky Reef Bushveld Complex South Africa 



Jean St-Pierre and Greg Kennedy are thanked for their work at the SLOWPOKE II reactor of the École Polytechnique (Montreal). This research was financed by the Canadian Research Chair in Magmatic Metallogeny. We thank the reviewers, Dr. Steve Barnes, Prof. Ed Ripley and the editor Prof. Lehmann, for their assistance in improving the clarity of the manuscript.


  1. Andersen JCO (2006) Postmagmatic sulphur loss in the Skaergaard Intrusion: implications for the formation of the Platinova Reef. Lithos 92:198–221CrossRefGoogle Scholar
  2. Ashwal LD, Webb SJ, Knoper MW (2005) Magmatic stratigraphy in the Bushveld Northern Lobe: continuous geophysical and mineralogical data from the 2950 m Bellevue drillcore. S Afr J Geol 108:199–232CrossRefGoogle Scholar
  3. Auclair G, Fouquet Y, Bohn M (1987) Distribution of Se in high-temperature hydrothermal sulfides at 13° north, East Pacific Rise. Can Min 25:577–587Google Scholar
  4. Barnes S-J, Maier WD (2002a) Platinum-group element distribution in the Merensky Reef, Impala Mine, Bushveld Complex. J Petrol 43:103–128CrossRefGoogle Scholar
  5. Barnes S-J, Maier W D (2002b) Platinum-group element distributions in the Rustenberg Layered Suite of the Bushveld Complex, South Africa. In: LJ Cabri (ed) The Geology, Geochemistry, Mineralogy and Mineral Beneficiation of Platinum-Group Elements. Canadian Institute of Mining, Metallurgy and Petroleum, Special Volume 54, pp 553–580Google Scholar
  6. Barnes S-J, Maier WD, Ashwal LD (2004) Platinum-group element distribution in the Main Zone and Upper Zone of the Bushveld Complex, South Africa. Chem Geol 208:293–317CrossRefGoogle Scholar
  7. Barnes S-J, Pritchard HM, Cox RA, Fisher PC, Godel B (2008) The location of the chalcophile and siderophile elements in platinum-group element ore deposits (a textural, microbeam and whole rock geochemical study): Implications for the formation of the deposits. Chem Geol 248:295–317CrossRefGoogle Scholar
  8. Bedard L P, Bernard J, Barnes S-J (2007) Searching for selenium: in situ measurement in base metal sulfides. Geochim Cosmochim Acta 71, A71 (abstr)Google Scholar
  9. Bédard LP, Savard D, Barnes S-J (2008) Total sulfur concentration in geological reference materials by elemental infrared analyser. Geostand Geoanal Res 32:203–208CrossRefGoogle Scholar
  10. Boudreau AE, Meurer WP (1999) Chromatographic separation of the platinum-group elements, gold, base metals and sulfur during degassing of a compacting and solidifying igneous crystal pile. Contrib Miner Petrol 134:174–185CrossRefGoogle Scholar
  11. Campbell IH, Naldrett AJ, Barnes S-J (1983) A model for the origin of the platinum-rich sulphide horizons in the Bushveld and Stillwater Complexes. J Petrol 24:133–165Google Scholar
  12. Cawthorn RG (1999) Platinum-group element mineralization in the Bushveld Complex—a critical reassessment of geochemical models. S Afr J Geol 102:268–281Google Scholar
  13. Cawthorn RG (2005) Contrasting sulphide contents of the Bushveld and Sudbury Igneous Complexes. Miner Depos 40:1–12CrossRefGoogle Scholar
  14. Cawthorn RG, Street J (1994) Vertical migration of residual magma in the Upper Zone of the Bushveld Complex. Miner Petrol 51:345–354CrossRefGoogle Scholar
  15. Cawthorn RG, Davies G, Clubley-Armstrong A, McCarthy TS (1981) Sills associated with the Bushveld Complex, South Africa: an estimate of the parental magma composition. Lithos 10:1–5CrossRefGoogle Scholar
  16. Curl E A (2001) Parental magmas of the Bushveld Complex, South Africa. PhD thesis, Monash UniversityGoogle Scholar
  17. Davies G, Tredoux M (1985) The Platinum-group element and gold contents of the marginal rocks and sills of the Bushveld Complex. Econ Geol 80:838–848CrossRefGoogle Scholar
  18. Davies G, Cawthorn RG, Barton JM, Morton M (1980) Parental magma to the Bushveld Complex. Nat 287:33–35CrossRefGoogle Scholar
  19. Dreibus G, Palme H, Spettel B, Zipfel J, Wänke H (1995) Sulfur and selenium in chondritic meteorites. Meteorit 30:439–445Google Scholar
  20. Eales HV (2002) Caveats in defining the magmas parental to the mafic rocks of the Bushveld Complex, and the manner of their emplacement: review and commentary. Miner Mag 66:815–832CrossRefGoogle Scholar
  21. Eckstrand O R, Grinenko L N, Krouse H R, Paktunc A D, Schwann P L, Scoates R F (1989) Preliminary data on sulphur isotopes and Se/S ratios, and the source of sulphur in magmatic sulphur in magmatic sulphides from the Fox River Sill, Molson Dykes and Thompson nickel deposits, northern Manitoba. In: Current Research, Part C. Geological Survey of Canada 89–1C, pp 235–242Google Scholar
  22. Eriksson PG, Schweitzer JK, Bosch PJA, Schreiber UM, van Deventer JL, Hatton CJ (1993) The Transvaal sequence: an overview. J Afr Earth Sci 16:25–51CrossRefGoogle Scholar
  23. Francis RD (1990) Sulfide globules in midocean ridge basalts (MORB), and the effect of oxygen abundance in Fe–S–O liquids on the ability of those liquids to partition metals from MORB and komatiite magmas. Chem Geol 85:199–213CrossRefGoogle Scholar
  24. Gaetani GA, Grove TL (1997) Partitioning of moderately siderophile elements among olivine, silicate melt, and sulfide melt: Constraints on core formation in the Earth and Mars. Geochim Cosmochim Acta 61:1829–1846CrossRefGoogle Scholar
  25. Gain SB (1985) The geological setting of the platiniferous UG-2 chromitite layer on the farm Maandagshoek, Eastern Bushveld Complex. Econ Geol 80:925–943CrossRefGoogle Scholar
  26. Gladney ES, Knab D (1981) Determination of selenium in twenty geological reference materials by neutron activation and inorganic ion exchange. Geostand Newsl 5:67–69CrossRefGoogle Scholar
  27. Godel B, Barnes S-J (2008a) Image analysis and composition of platinum-group minerals in the J-M Reef, Stillwater Complex. Econ Geol 103:637–651CrossRefGoogle Scholar
  28. Godel B, Barnes S-J (2008b) Platinum-group elements in sulfide minerals and the whole rock of the J-M Reef (Stillwater Complex): Implication for the formation of the reef. Chem Geol 248:272–294CrossRefGoogle Scholar
  29. Godel B, Barnes S-J, Maier WD (2006) 3-D distribution of sulphide minerals in the Merensky Reef (Bushveld Complex, South Africa) and the J-M Reef (Stillwater Complex, USA) and their relationship to microstructures using X-ray computed tomography. J Petrol 47:1853–1872CrossRefGoogle Scholar
  30. Godel B, Barnes S-J, Maier WD (2007) Platinum-group elements in sulphide minerals, platinum-group minerals, and whole-rocks of the Merensky Reef (Bushveld Complex, South Africa): Implication for the formation of the Reef. J Petrol 48:1569–1604CrossRefGoogle Scholar
  31. Govindaraju K (1994) 1994 compilation of working values and sample description for 383 geostandards. Geostand Newsl 18:1–158Google Scholar
  32. Guo J, Griffin WL, O'Reilly SY (1999) Geochemistry and origin of sulphide minerals in mantle xenoliths; Qilin, southeastern China. J Petrol 40:1125–1149CrossRefGoogle Scholar
  33. Hall GEM, MacLaurin AI, Pelchat JC, Gauthier G (1997) Comparison of the techniques of atomic absorption spectrometry and inductively coupled plasma mass spectrometry in the determination of Bi, Se and Te by hydride generation. Chem Geol 137:79–89CrossRefGoogle Scholar
  34. Harmer RE, Sharpe MR (1985) Field relations and strontium isotope systematics of the marginal rocks of the eastern Bushveld Complex. Econ Geol 80:813–837CrossRefGoogle Scholar
  35. Harmer R E, Armstrong R A (2000) Duration of Bushveld Complex (sensu lato) magmatism: constraints from new SHRIMP zircon chronology. Abstracts and program, Workshop on the Bushveld Complex, Gethane Lodge, Burgersfort, South AfricaGoogle Scholar
  36. Harney DMW, Merkle RKW, Von Gruenewaldt G (1990) Platinum-group element behavior in the lower part of the Upper Zone, Eastern Bushveld Complex—implications for the formation of the Main Magnetite Layer. Econ Geol 85:1777–1789CrossRefGoogle Scholar
  37. Hattori KH, Arai S, Clarke DB (2002) Selenium, tellurium, arsenic and antimony contents of primary mantle sulfides. Can Miner 40:637–650CrossRefGoogle Scholar
  38. Hiemstra SA (1979) The role of collectors in the formation of the platinum deposits of the Bushveld Complex. Can Miner 17:469–482Google Scholar
  39. Holzheid A, Lodders K (2001) Solubility of copper in silicate melts as function of oxygen and sulfur fugacities, temperature, and silicate composition. Geochim Cosmochim Acta 65:1933–1951CrossRefGoogle Scholar
  40. Kruger FJ (1994) The Sr-isotropic stratigraphy of the western Bushveld Complex. S Afr J Geol 97:393–398Google Scholar
  41. Li CS, Ripley EM (2005) Empirical equations to predict the sulfur content of mafic magmas at sulfide saturation and applications to magmatic sulfide deposits. Miner Dep 40:218–230CrossRefGoogle Scholar
  42. Lorand JP, Alard O, Luguet A, Keays RR (2003) Sulfur and selenium systematics of the subcontinental lithospheric mantle: inferences from the Massif Central xenolith suite (France). Geochim Cosmochim Acta 67:4137–4151CrossRefGoogle Scholar
  43. Maier WD (2005) Platinum-group element (PGE) deposits and occurrences: Mineralization styles, genetic concepts, and exploration criteria. J Afr Earth Sci 41:165–191CrossRefGoogle Scholar
  44. Maier WD, Barnes S-J (1998) Concentrations of rare earth elements in silicate rocks of the Lower, Critical and Main Zones of the Bushveld complex. Chem Geol 150:85–103CrossRefGoogle Scholar
  45. Maier WD, Barnes S-J (1999) Platinum-group elements in silicate rocks of the Lower, Critical and Main Zones at Union Section, Western Bushveld Complex. J Petrol 40:1647–1671CrossRefGoogle Scholar
  46. Marin L, Lhomme J, Carignan J (2001) Determination of selenium concentration in sixty five reference materials for geochemical by GFAAS after separation with thiol cotton. Geostand Newsl 25:317–324CrossRefGoogle Scholar
  47. McDonough WF, Sun S-S (1995) The composition of the Earth. Chem Geol 120:223–253CrossRefGoogle Scholar
  48. Mitchell AA (1990) The stratigraphy, petrography and mineralogy of the Main Zone of the northwestern Bushveld Complex. S Afr J Geol 93:818–831Google Scholar
  49. Naldrett AJ, Duke JM, Lightfoot PC, Thompson JFH (1984) Quantitative modeling of the segregation of magmatic sulfides—an exploration guide. Can Inst Miner Meteor Bull 77:46–57Google Scholar
  50. Okai T, Terashima S, Imai N (2001) Determination of total Sulfur in thirty one geochemical reference materials using an inductively coupled plasma-atomic emission spectrometer fitted with a semiconductor photodiode detector. Geostand Geoanal Res 25:133–136CrossRefGoogle Scholar
  51. Paktunc AD, Hulbert LJ, Harris DC (1990) Partitioning of the platinum-group and other trace elements in sulfides from the Bushveld Complex and Canadian occurrences of nickel–copper sulfides. Can Miner 28:475–488Google Scholar
  52. Peach CL, Mathez EA, Keays RR (1990) Sulfide melt–silicate melt distribution coefficients for noble metals and other chalcophile elements as deduced from MORB: implication for partial melting. Geochim Cosmochim Acta 54:3379–3389CrossRefGoogle Scholar
  53. Peregoedova A, Barnes S-J, Baker DR (2004) The formation of the Pt–Ir alloys and Cu–Pd rich sulfide melts by partial desulfurization of Fe–Ni–Cu sulfides: results of experiments and implications for natural systems. Chem Geol 208:247–264CrossRefGoogle Scholar
  54. Peregoedova A, Barnes S-J, Baker DR (2006) An experimental study of mass transfer of platinum-group elements, gold, nickel and copper in sulfur-dominated vapor at magmatic temperatures. Chemical Geology 235:59–75CrossRefGoogle Scholar
  55. Ripley EM, Li C, Shin D (2002a) Paragneiss assimilation in the genesis of magmatic Ni–Cu–Co sulfide mineralization at Voisey's Bay, Labrador: delta S-34, delta C-13, and Se/S evidence. Econ Geol 97:1307–1318CrossRefGoogle Scholar
  56. Ripley EM, Brophy JG, Li C (2002b) Copper solubility in a basaltic melt and sulfide liquid/silicate melt partition coefficients of Cu and Fe. Geochim Cosmochim Acta 15:2791–2800CrossRefGoogle Scholar
  57. Savard D, Bédard LP, Barnes S-J (2006) TCF selenium preconcentration in geological materials for determination at sub-µg g−1 with INAA (Se/TCF-INAA). Talanta 70:566–571CrossRefGoogle Scholar
  58. Scoats JS, Friedman RM (2008) Precise age of the platiniferous Merensky reef, Bushveld Complex, South Africa, by U–Pb zircon chemical abrasion ID-TIMS technique. Econ Geol 103:465–471CrossRefGoogle Scholar
  59. Sharpe MR (1981) The chronology of magma influxes to the eastern compartment of the Bushveld Complex as exemplified by its marginal border groups. J Geol Soc 138:307–326CrossRefGoogle Scholar
  60. Sharpe MR, Hulbert LJ (1985) Ultramafic sills beneath the eastern Bushveld Complex: mobilized suspensions of early Lower Zone cumulates in a parental magma with boninitic affinities. Econ Geol 80:849–871CrossRefGoogle Scholar
  61. Steele T W, Levin J, Copelowitz I (1975) The preparation and certification of a reference sample of a precious-metal ore. NIM-Report 1696-04771, The National Institute for Metallurgy, JohannesburgGoogle Scholar
  62. Taylor SR, McLennan SM (1985) The continental crust; its composition and evolution: an examination of the geochemical record preserved in sedimentary rocks. Blackwell, OxfordGoogle Scholar
  63. Teigler B, Eales HV (1996) The Lower and Critical Zones of the western limb of the Bushveld Complex as intersected by the Nooitgedacht boreholes. Geol Surv S Afr Bull 111:126Google Scholar
  64. Terashima S, Imai N (2000) Determination of selenium in fifty two geochemical reference materials by hydride generation atomic absorption spectrometry. Geostand Newsl 24:83–86CrossRefGoogle Scholar
  65. Thériault R, Barnes S-J (1998) Compositional variations in Cu–Ni–PGE sulfides of the Dunka Road deposit, Duluth Complex, Minnesota: the importance of combined assimilation and magmatic processes. Can Miner 36:869–886Google Scholar
  66. Tredoux M, Lindsay NM, Davies G, McDonald I (1995) The fractionation of platinum-group elements in magmatic systems, with the suggestion of a novel causal mechanism. S Afr J Geol 98:157–167Google Scholar
  67. Von Gruenewaldt G, Hatton CJ, Merkle RKW, Gain SB (1986) Platinum-group element–chromitite associations in the Bushveld Complex. Econ Geol 81:1067–1079CrossRefGoogle Scholar
  68. Wallace P, Carmichael ISE (1992) Sulfur in basaltic magmas. Geochim Cosmochim Acta 56:1863–1874CrossRefGoogle Scholar
  69. Willmore CC, Boudreau AE, Kruger FJ (2000) The halogen geochemistry of the Bushveld Complex, Republic of South Africa: implications for chalcophiles element distribution in the Lower and Critical Zones. J Petrol 41:1517–1539Google Scholar
  70. Wilson A, Chunnet G (2006) Trace elements and platinum group element distributions and the genesis of the Merensky Reef, Western Bushveld Complex, South Africa. J Petrol 47:2369–2403CrossRefGoogle Scholar
  71. Wulf AV, Palme H, Jochum KP (1995) Fractionation of volatile elements in the early solar system: evidence from heating experiments on primitive meteorites. Planet Space Sci 43:451–468CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Sarah-Jane Barnes
    • 1
    Email author
  • Dany Savard
    • 1
  • L. Paul Bédard
    • 1
  • Wolfgang D. Maier
    • 2
  1. 1.Sciences de la TerreUniversité du Québec à ChicoutimiChicoutimiCanada
  2. 2.Centre for Exploration TargetingUniversity of Western AustraliaCrawleyAustralia

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