| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Petrology Volume 41 Number 4 Pages 545-561 2000
© Oxford University Press 2000
Noble Metal Enrichment Processes in the Merensky Reef, Bushveld Complex

1RSES, AUSTRALIAN NATIONAL UNIVERSITY, CANBERRA, A.C.T. 0200, AUSTRALIA
2GEOLOGY DEPARTMENT, AUSTRALIAN NATIONAL UNIVERSITY, CANBERRA, A.C.T. 0200, AUSTRALIA
We have analysed sulphides, silicates, and chromites of the Merensky Reef for platinum-group elements (PGEs), Re and Au using laser ablation-inductively coupled plasma mass spectrometry and synthetic pyrrhotite standards annealed with known quantities of noble metals. Os, Ir and Ru reside in solid solution in pyrrhotite and pentlandite, Rh and part of the Reefs Pd in pentlandite, whereas Pt, Au, Re and some Pd form discrete phases. Olivine and chromite, often suspected to carry Os, Ir and Ru, are PGE free. All phases analysed contain noble metals as discrete micro-inclusions with diameters typically <100 nm. Inclusions in sulphides commonly have the element combinations OsIrPt and PtPdAu. Inclusions in olivine and chromite are dominated by Pt ± AuPd. Few inclusion spectra can be related to discrete noble metal phases, and few inclusions have formed by sub-solidus exsolution. Rather, some PGE inclusions, notably those in olivine and chromite, are early-magmatic nuggets trapped when their host phases crystallized. We suggest that the silicate melt layer that preceded the Merensky Reef was PGE oversaturated at early cumulus times. Experiments combined with available sulphidesilicate partition coefficients suggest that a silicate melt in equilibrium with a sulphide melt containing the PGE spectrum of the Merensky ore would indeed be oversaturated with respect to the least soluble noble metals. Sulphide melt apparently played little role in enriching the noble metals in the Merensky Reef; rather, its role was to immobilize a pre-existing in situ stratiform PGE anomaly in the liquid-stratified magma chamber.
KEY WORDS: Bushveld Complex; Merensky Reef; laser-ablation ICP-MS; platinum-group mineralization
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
A. J. Naldrett, A. Wilson, J. Kinnaird, and G. Chunnett PGE Tenor and Metal Ratios within and below the Merensky Reef, Bushveld Complex: Implications for its Genesis J. Petrology, April 20, 2009; (2009) egp015v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Gonzalez-Jimenez, F. Gervilla, J. A. Proenza, T. Kerestedjian, T. Auge, and L. Bailly Zoning of laurite (RuS2)-erlichmanite (OsS2): implications for the origin of PGM in ophiolite chromitites European Journal of Mineralogy, April 1, 2009; 21(2): 419 - 432. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. S. Finnigan, J. M. Brenan, J. E. Mungall, and W. F. McDonough Experiments and Models Bearing on the Role of Chromite as a Collector of Platinum Group Minerals by Local Reduction J. Petrology, September 6, 2008; (2008) egn041v1. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. M. Brenan The Platinum-Group Elements: "Admirably Adapted" for Science and Industry Elements, August 1, 2008; 4(4): 227 - 232. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Godel, S.-J. Barnes, and W. D. Maier Platinum-Group Elements in Sulphide Minerals, Platinum-Group Minerals, and Whole-Rocks of the Merensky Reef (Bushveld Complex, South Africa): Implications for the Formation of the Reef J. Petrology, August 1, 2007; 48(8): 1569 - 1604. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. WILSON and G. CHUNNETT Trace Element and Platinum Group Element Distributions and the Genesis of the Merensky Reef, Western Bushveld Complex, South Africa J. Petrology, December 1, 2006; 47(12): 2369 - 2403. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. GODEL, S.-J. BARNES, and W. D. MAIER 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. Petrology, September 1, 2006; 47(9): 1853 - 1872. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. S. Smith, I. J. Basson, and D. L. Reid NORMAL REEF SUBFACIES OF THE MERENSKY REEF AT NORTHAM PLATINUM MINE, ZWARTKLIP FACIES, WESTERN BUSHVELD COMPLEX, SOUTH AFRICA Can Mineral, April 1, 2004; 42(2): 243 - 260. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. Li, E. M. Ripley, E. Merino, and W. D. Maier REPLACEMENT OF BASE METAL SULFIDES BY ACTINOLITE, EPIDOTE, CALCITE, AND MAGNETITE IN THE UG2 AND MERENSKY REEF OF THE BUSHVELD COMPLEX, SOUTH AFRICA Economic Geology, January 1, 2004; 99(1): 0173 - 184. [Abstract] [Full Text] [PDF] |
||||
![]() |
L. J. Cabri, P. J. Sylvester, M. N. Tubrett, A. Peregoedova, and J.H. G. Laflamme COMPARISON OF LAM ICP MS AND MICRO-PIXE RESULTS FOR PALLADIUM AND RHODIUM IN SELECTED SAMPLES OF NORIL'SK AND TALNAKH SULFIDES Can Mineral, April 1, 2003; 41(2): 321 - 329. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. G. Hinchey, D. H.C. Wilton, and M. N. Tubrett A LAM ICP MS STUDY OF THE DISTRIBUTION OF GOLD IN ARSENOPYRITE FROM THE LODESTAR PROSPECT, NEWFOUNDLAND, CANADA Can Mineral, April 1, 2003; 41(2): 353 - 364. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. E. MUNGALL Kinetic Controls on the Partitioning of Trace Elements Between Silicate and Sulfide Liquids J. Petrology, May 1, 2002; 43(5): 749 - 768. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. G. Cawthorn, C. A. Lee, R. P. Schouwstra, and P. Mellowship RELATIONSHIP BETWEEN PGE AND PGM IN THE BUSHVELD COMPLEX Can Mineral, April 1, 2002; 40(2): 311 - 328. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Peregoedova and M. Ohnenstetter COLLECTORS OF Pt, Pd AND Rh IN A S-POOR Fe Ni Cu SULFIDE SYSTEM AT 760{degrees}C: EXPERIMENTAL DATA AND APPLICATION TO ORE DEPOSITS Can Mineral, April 1, 2002; 40(2): 527 - 561. [Abstract] [Full Text] [PDF] |
||||
![]() |
P. Sattari, P. Sattari, J. M. Brenan, I. Horn, and W. F. McDonough Experimental Constraints on the Sulfide- and Chromite-Silicate Melt Partitioning Behavior of Rhenium and Platinum-Group Elements Economic Geology, March 1, 2002; 97(2): 385 - 398. [Abstract] [Full Text] [PDF] |
||||
![]() |
S.-J. BARNES and W. D. MAIER Platinum-group Elements and Microstructures of Normal Merensky Reef from Impala Platinum Mines, Bushveld Complex J. Petrology, January 1, 2002; 43(1): 103 - 128. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. H. Wilson and M. D. Prendergast Platinum-Group Element Mineralisation in the Great Dyke, Zimbabwe, and its Relationship to Magma Evolution and Magma Chamber Structure South African Journal of Geology, December 1, 2001; 104(4): 319 - 342. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. H. WILSON Compositional and Lithological Controls on the PGE-Bearing Sulphide Zones in the Selukwe Subchamber, Great Dyke: a Combined Equilibrium-Rayleigh Fractionation Model J. Petrology, October 1, 2001; 42(10): 1845 - 1867. [Abstract] [Full Text] [PDF] |
||||
![]() |
C. BALLHAUS, M. TREDOUX, and A. SPATH Phase Relations in the Fe-Ni-Cu-PGE-S System at Magmatic Temperature and Application to Massive Sulphide Ores of the Sudbury Igneous Complex J. Petrology, October 1, 2001; 42(10): 1911 - 1926. [Abstract] [Full Text] [PDF] |
||||





