Fig. 11
Sulfur isotopic compositions of the late Miocene epithermal deposits in the central Andes. Sulfur isotope data are taken from Campbell84, Deen66, Deyell et al.50, Fifarek and Rye51, Rainbow et al.85, Rye61, Cerpa et al.53 and this study (for Laurani deposit; the three stage II barite-sulfide pairs from the samples ZK4R60, LFT5 with LFT10, and LFT13 with LFT15 in Table 3, the last two sample pairs are taken from the two same orebodies, respectively). The original diagram is modified after Rye61. The nearly horizontal line through the hydrothermal and igneous data reflects a combination of disequilibrium in the igneous system and late hydrothermal systems and the average equilibrium values for magmatic-hydrothermal alunite in an overall H2S-dominant system61; the near-vertical line represents the local shift to a SO2−4-dominant system during acid sulfate alteration61. R is defined in terms of SO2−4/H2S61.
