The occurrence of platinum-group element and gold minerals in the Bon Accord Ni-oxide body, South Africa

Petrogenesis of the Platinum-Group Minerals

“…Although heavy mineral separation techniques were used by Zaccarini et al to isolate the PGM, they were able to provide some textural context for the PGM, which appear to be preferentially sited close to the edges of Ni-arsenide and Ni-antimonide grains, in turn typically encased in trevorite grains. Zaccarini et al (2014) suggest that the observed assemblage was formed during a hydrothermal or low temperature metamorphic episode, possibly during exhumation of the body, but this plausibly lends support to the origin of Bon Accord as an altered Ni-sulfide deposit too. It is difficult to speculate much further than this on the petrogenesis of the PGM assemblage in the Bon Accord deposit.…”

“…This is not surprising, since Tredoux et al (1989) reported ppm levels of the PGE. Zaccarini et al (2014) report a variety of Pd-Sb Pd-Sb, Pd-Sb-As, Pd-Cu-Sb, Pt-Sb, Pt-As-S, Ru-As-S, and Ru-S phases, as well as sperrylite and phases in the solid solution series sobolevskite-kotulskite. Electrum was also reported.…”

“…Although formation of the deposit as an oxidized volcanic massive sulfide (VMS) deposit or as a modified Ni-sulfide deposit was also ruled out by the latter authors, these possibilities have recently been revisited (O'Driscoll et al 2014b). Zaccarini et al (2014) and Tredoux et al (in press) have recently reported the presence of PGM in Bon Accord material. This is not surprising, since Tredoux et al (1989) reported ppm levels of the PGE.…”

Nanoscale Structure of Zoned Laurites from the Ojén Ultramafic Massif, Southern Spain

“…There is a consensus that a progressive increase in the Os content of laurite would be expected on cooling because of both decreasing temperature and increasing f S 2 , thus normal zoning should reflect the different stages of fractional crystallization during cooling of the chromitite parental melt [42,[47][48][49]. In contrast, oscillatory zoning consisting of bands of Os-poor and Os-rich laurite often alternating with irarsite (Figures 2d and 3c) indeed highlight the existence of a magmatic system with different f S 2 (and a As) gradients in space and/or time, with or without changes in temperature, and over short time spans [6,8,11].…”

Forschungsbereiche der Angewandten Geowissenschaften an der Montanuniversität Leoben

“…tal), Nb-Ta Prospektion, Elemente der Platingruppe in Verwitterungslagerstätten [17]. z Mineralogie und Lagerstätten der Edelmetalle: konventionelle PGE-Lagerstätten in ultramafischen Gesteinen, neue Platingruppen-Minerale (PGM), Goldlagerstätten in den Alpen [18].…”