Figure F3. Photomicrographs of massive sulfide (Sample 331-C0016B-1L-1, 18–20 cm). A. Illite/muscovite-altered volcanic clast (indicated), containing disseminated pyrite and quartz fragments cemented in quartz-muscovite-sulfide (pyrite-sphalerite-chalcopyrite-galena) (plane-polarized light [PPL]; ×10). B. Same as A (reflected light [RL]; ×10). Sulfide phases are indicated. Py = pyrite, Cp = chalcopyrite, Sp = sphalerite, Gn = galena. C. Pyrite-chalcopyrite-sphalerite-galena intergrowth (RL; ×20). Chalcopyrite overgrows pyrite, and sphalerite shows chalcopyrite disease. D. Early subhedral sphalerite with a later overgrowth of sphalerite (PPL; ×5). E. Colloform/atoll-textured sphalerite overgrowing pyrite and chalcopyrite (RL; ×5). F. Coarse anhydrite overgrowing quartz and sulfide (PPL; ×2.5).
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