Metamorphic alteration of the massive sulfide horizon from the Salt River VMS deposit (South Africa)

Sulfides from the upper sulfide zone of the Salt River VMS deposit (South Africa) were analyzed for PGE (platinum group elements), Re, Au, Sb, As, Se, Te, Cr, Co, Ni, Mn, Mo, Ag, Hg and Pb using in-situ LA-ICP-MS (laser ablation-inductively coupled plasma-mass spectrometry) techniques. The analysis of a plethora of trace elements during the ablation of one single spot was possible by using a multi-standard approach, involving the analysis of several external standards before, after and between the analysis of unknowns, including a new in-house standard for As, Sb, Se, and Te. Chondrite normalized PGE patterns best fit data from Besshi-type deposits, and show that metamorphism was isochemical with respect to the PGE and Au. Although most sulfide minerals experienced melting no migration into discrete pockets could be observed.