FIG. 17. Pd vs. Cu/Pd plot for samples from the southern Roby and Twilight zones compared to other PGE deposits. Note that the rocks from Lac des Iles show a wide variation in Cu/Pd ratios. The mineralized melanocratic rocks show low Cu/Pd ratios, similar to those for other primary PGE deposits, whereas the barren leucocratic rocks display high Cu/Pd ratios. Abbreviations: JM = JM reef, Stillwater, United States (Barnes and Naldrett, 1985); MR = Merensky reef, Bushveld (Maier et al., 1996) and UG = UG2 reef, Bushveld (Maier and Bowen, 1996), South Africa; N = Noril’sk (Smirnov, 1966), FP = Federov Pansky (Schissel et al., 2002), Russia; Sud = Sudbury, Canada (Naldrett, 1981).