New data on malanite and cuprorhodsite from chromitites of the Bushveld Complex

Rudashevsky N. S., Rudashevsky V. N.

Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2019. V. 148. N 5. P. 126-134

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Language: Russian 


The 3D mineralogical technology was used to study the representative selection of grains of thiospineles from 3 groups of chromitite horizons (lower LG6, middle MG1/MG2 and upper UG2): 46 grains of malanite (4—42 μm) and 34 grains of cuprorhodsite (9—42 μm). Their microprobe analysis was performed (n = 61). Statistics for this selection have resulted in following formulae: for malanite — (Сu2+,Fe2+)(Pt3+,Rh3+,Ir3+,Co3+,Ni3+Fe3+)2S4, for cuprorhodsite — (Сu2+,Fe2+) ∙ (Rh3+,Pt3+,Ir3+,Fe3+)2S4. According to morphological properties and their relationship with platinum-group minerals (PGM) and base metal sulphides, thiospinel can be attributed as the earliest primary PGM in chromitites. The distribution of cuprorhodsite and malanite in chromitites was controlled by the Rayleigh fractionation of the primary sulfide melt in the process of formation of Bushveld chromitite horizons.

Key words: malanite, cuprorhodsite, thioshpinels, Bushveld Complex, chromitites, distribution of PGM, 3D-mineralogical investigation technology