Metallogeny of the Dagangou Au-Ag-Cu-Sb Deposit in the Eastern Kunlun Orogen, NW China: Constraints from Ore-Forming Fluid Geochemistry and S-H-O Isotopes

Figure 3

Representative photos of the hand specimen and micrographs of ores in the Dagangou Au-Ag-Cu-Sb deposit. (a) The quartz-vein-type Cu ore from K3-1 Cu-Ag ore body. The xenomorphic chalcocites filled in the interspace between ankerite and quartz. (b) The chalcopyrite is filled between quartz grains, and chalcocite is metasomatized along the chalcopyrite fissure or interior (plane-polarized light). (c) The stibnite-quartz vein cuts the earlier quartz vein, and sulfides are mainly stibnite with a small amount of pyrite and chalcopyrite. (d) The automorphic pyrite disseminate in the silicified rocks with clear borders (plane-polarized light), and they contain little gold. (e) The xenomorphic stibnite surround the automorphic quartz, indicating the quartz crystallized earlier than stibnite. (f) The quartz stringer crosscuts the earlier stibnite, and the polysynthetic twins of stibnite are remarkable (crossed polarized light). Ank: ankerite; Ccp: chalcopyrite; Cct: chalcocite; Mlc: malachite; Py: pyrite; Qz: quartz; Stb: stibnite. The abbreviation for minerals is cited from Whitney and Evans [40].

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