Research Article| September 01, 2005 Major and trace element geochemistry of the Platreef on the farm Townlands, northern Bushveld Complex Tawanda D. Manyeruke; Tawanda D. Manyeruke Centre for Research on Magmatic Ore Deposits (CERMOD), Geology Department, University of Pretoria, Pretoria 0002, South Africa, e-mail: s22377523@tuks.co.za and wdmaier@scientia.up.ac.za Search for other works by this author on: GSW Google Scholar Wolfgang D. Maier; Wolfgang D. Maier Centre for Research on Magmatic Ore Deposits (CERMOD), Geology Department, University of Pretoria, Pretoria 0002, South Africa, e-mail: s22377523@tuks.co.za and wdmaier@scientia.up.ac.za Search for other works by this author on: GSW Google Scholar Sarah-Jane Barnes Sarah-Jane Barnes Université du Québec à Chicoutimi, 555 Boulevard Université, Chicoutimi, Québec, G7H 2B1, e-mail: sjbarnes@uquc.ca Search for other works by this author on: GSW Google Scholar Author and Article Information Tawanda D. Manyeruke Centre for Research on Magmatic Ore Deposits (CERMOD), Geology Department, University of Pretoria, Pretoria 0002, South Africa, e-mail: s22377523@tuks.co.za and wdmaier@scientia.up.ac.za Wolfgang D. Maier Centre for Research on Magmatic Ore Deposits (CERMOD), Geology Department, University of Pretoria, Pretoria 0002, South Africa, e-mail: s22377523@tuks.co.za and wdmaier@scientia.up.ac.za Sarah-Jane Barnes Université du Québec à Chicoutimi, 555 Boulevard Université, Chicoutimi, Québec, G7H 2B1, e-mail: sjbarnes@uquc.ca Publisher: Geological Society of South Africa First Online: 09 Mar 2017 Online ISSN: 1996-8590 Print ISSN: 1012-0750 © 2005 Geological Society of South Africa South African Journal of Geology (2005) 108 (3): 381–396. https://doi.org/10.2113/108.3.381 Article history First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Tawanda D. Manyeruke, Wolfgang D. Maier, Sarah-Jane Barnes; Major and trace element geochemistry of the Platreef on the farm Townlands, northern Bushveld Complex. South African Journal of Geology 2005;; 108 (3): 381–396. doi: https://doi.org/10.2113/108.3.381 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract The Platreef is a platinum group elements and base metal enriched mafic/ultramafic layer situated along the base of the northern limb of the Bushveld Complex. The present study contains a detailed petrographic and geochemical investigation of a borehole core intersection through the Platreef on the farm Townlands. At this locality, the Platreef rests on metasedimentary rocks of the Silverton Formation of the Transvaal Supergroup, and is comprised of three medium-grained units of gabbronorite/feldspathic pyroxenite that are separated by hornfels interlayers. We refer to the three platiniferous layers as the Lower, Middle and Upper Platreef. The Middle Platreef is the main mineralised layer, with total PGE contents up to 4 ppm. The Lower and Upper Platreefs are less well mineralised (up to 1.5 ppm).Trace element and S-isotope data show compositional breaks between the different platiniferous layers suggesting that they represent distinct sill-like intrusions of pyroxene and sulphide enriched crystal mushes. The study also reveals a reversed differentiation trend of more primitive rocks towards the top of the succession. For example, orthopyroxene shows an increase in Cr2O3 from 0.07 to 0.37 weight % with height and the whole rock concentration of incompatible trace elements such as Y and Zr decreases. This pattern is interpreted to reflect enhanced crustal contamination of the lower Platreef layers.All three Platreef layers are enriched in heavy S (δ34S of 2.6 to 9.1 ‰) indicating addition of crustal sulphur, and they have elevated K, Ca, Zr and Y contents and high Zr/Y ratio relative to Critical Zone rocks from elsewhere in the Bushveld Complex, suggesting a model of crustal contamination in ore formation.Well defined correlations between the concentrations of the individual PGE, and between the PGE and S suggest that the concentration of the PGE was controlled by segregating sulphide melt. Alteration of the rocks, possibly due to infiltration by fluids derived from the floor rocks, caused localized redistribution of Cu, S and, to a lesser degree, the PGE. However, alteration, sulphur and metal mobility was apparently much less pronounced at Townlands than at other Platreef localities further to the north, notably at Sandsloot mine where the PGE are largely hosted by PGM (Armitage et al., 2002). We suggest that this is due to more pronounced devolatisation of the dolomites relative to the shales, implying that the nature of the floor rocks plays an important role in ore formation. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.