Quantitative mineralogy, mineral chemistry and microtex-tural data on the UG2 chromitite intruded by iron-rich ul-tramafic pegmatite (IRUP) at the Thaba Mine, northwest-ern Bushveld Complex, South Africa

Zhou, Haoyang; Appelt, Oona; Tjallingii, Rik; Bachmann, Kai; Trumbull, Robert B.;

2023 || GFZ Data Services

Discordant iron-rich ultramafic pegmatites (IRUPs) intersect the UG2 chromitite at many places in the Bushveld Complex but the effects on ore grade and mineralogy have rarely been studied in detail. We investigated a drillcore profile through the UG2 layer affected by IRUP intrusions at Tha-ba mine, NW Bushveld. The work involved quantitative assessment of the ore mineralogy from mineral liberation analysis (MLA), chemical analyses of the main silicate and oxide minerals by elec-tron microprobe (EPMA) and micro-X-ray fluorescence (micro-XRF) element maps of the UG2-IRUP contacts.

The data reveal features of UG2-IRUP interaction at different scales. The micro-XRF study of the contacts shows that a thin layer of Fe-Ti-Cr spinel and ilmenite formed on the IRUP side, while chromite on the UG2 side underwent grain coarsening with loss of interstitial space, and developed chemical gradients in Cr, Al, Fe and Ti. On a larger scale, the MLA data document changes in ore and gangue mineral assemblages through most of the meter-thick UG2 layer. This includes formation of secondary hydrous silicates, replacement of PGE- sulfides by PGE alloys and PGE- As-Sb-Bi-Te-Pb phases, and formation of secondary Ni-Cu-Fe sulfides after pentlandite and chalcopyrite.

Originally assigned keywords

Corresponding MSL vocabulary keywords

MSL enriched keywords

MSL enriched sub domains
  • geochemistry
  • microscopy and tomography
Source http://dx.doi.org/10.5880/gfz.3.1.2022.005
Source publisher GFZ Data Services
DOI 10.5880/gfz.3.1.2022.005
Authors
  • Zhou, Haoyang
  • 0000-0002-0079-503X
  • Natural History Museum, University of Oslo, Oslo, Norway; GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Appelt, Oona
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Tjallingii, Rik
  • 0000-0002-9723-3622
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Bachmann, Kai
  • Helmholtz-Centre Dresden-Rossendorf, Helmholtz Institute Freiberg of Resource Technology, Freiberg, Germany;
  • Trumbull, Robert B.
  • 0000-0002-1999-4653
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
Contributors
  • Microprobe Lab (GFZ German Research Centre for Geosciences, Germany)
  • HostingInstitution
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Laboratory for XRF Element Scanning ((GFZ German Research Centre for Geosciences, Germany)
  • HostingInstitution
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
  • Trumbull, Robert B.
  • ContactPerson
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
References
  • Zhou, H., Trumbull, R. B., Veksler, I. V., & Bachmann, K. (2023). The effects of iron-rich ultramafic pegmatite on the composition and mineralogy of the UG2 chromitite: a case study in the western Bushveld Complex, South Africa. Mineralium Deposita, 58(6), 1005–1021. https://doi.org/10.1007/s00126-023-01167-x
  • 10.1007/s00126-023-01167-x
  • IsSupplementTo
  • Bachmann, K., Frenzel, M., Krause, J., & Gutzmer, J. (2017). Advanced Identification and Quantification of In-Bearing Minerals by Scanning Electron Microscope-Based Image Analysis. Microscopy and Microanalysis, 23(3), 527–537. https://doi.org/10.1017/s1431927617000460
  • 10.1017/S1431927617000460
  • Cites
  • Bachmann, K., Osbahr, I., Tolosana-Delgado, R., Chetty, D., & Gutzmer, J. (2018). Variation in Platinum Group Mineral and Base Metal Sulfide Assemblages in the Lower Group Chromitites of the Western Bushveld Complex, South Africa. The Canadian Mineralogist, 56(5), 723–743. https://doi.org/10.3749/canmin.1700094
  • 10.3749/canmin.1700094
  • Cites
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  • Cites
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  • Cites
Contact
  • Trumbull, Robert B.
  • GFZ German Research Centre for Geosciences, Potsdam, Germany;
Citation Zhou, H., Appelt, O., Tjallingii, R., Bachmann, K., & Trumbull, R. B. (2023). Quantitative mineralogy, mineral chemistry and microtex-tural data on the UG2 chromitite intruded by iron-rich ul-tramafic pegmatite (IRUP) at the Thaba Mine, northwest-ern Bushveld Complex, South Africa [Data set]. GFZ Data Services. https://doi.org/10.5880/GFZ.3.1.2022.005
Geo location(s)
  • Thaba Mine, northwestern Bushveld Complex, South Africa