Fluid Evolution of Fuzishan Skarn Cu-Mo Deposit from the Edong District in the Middle-Lower Yangtze River Metallogenic Belt of China: Evidence from Petrography, Mineral Assemblages, and Fluid Inclusions

Figure 6

Photomicrographs of representative samples under transmitted plane polarized light (e, i–l) and reflected plane polarized light (a–d, f–h) illustrating mineral assemblages, textures of ores, and alterations in the Fuzishan Cu-Mo deposit. (a) Euhedral pyrite and anhedral chalcopyrite that replace along the margin of pyrite in cryptocrystalline to fine-grained quartz vein. (b) Rosy bornite occurring as relicts replaced by grey-white chalcocite in diopside skarn. (c) Chalcopyrite decomposed along the margin or within bornite as irregular bands in marble. (d) Chalcopyrite decomposed in the form of emulsion texture in sphalerite in quartz vein. (e) Bornite, chalcocite, and coexisting late anhydrite in the interstitial space of diopside skarn. (f) Chalcopyrite together with quartz replacing magnetite. (g) Bornite + quartz veinlet crosscutting hematite. (h) Plate-like molybdenite superimposed by subsequent chalcopyrite and bornite in quartz vein. (i) Cracked euhedral garnet replaced by quartz-sulfide stage calcite. (j) Actinolite and epidote replacing diopside, eventually crosscut by the late anhydrite of the quartz-sulfide stage. (k) The cubic diopside in the prograde skarn stage replaced by epidote of the retrograde skarn stage. (l) Garnet nearly replaced by epidote and retaining euhedral crystal morphology. Py: pyrite; Cpy: chalcopyrite; Bn: bornite; Cct: chalcocite; Mol: molybdenite; Sph: sphalerite; Mt: magnetite; Hem: hematite; Grt: garnet; Di: diopside; Ep: epidote; Kfs: k-feldspar; Adr I: early anhydrite; Adr II: late anhydrite; Cal: calcite.

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