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The Bangbu gold deposit is a large orogenic gold deposit in Tibet formed during the AlpineHimalayan collision. Ore bodies(auriferous quartz veins) are controlled by the E-W-trending Qusong-Cuogu-Zhemulang brittle-ductile shear zone. Quartz veins at the deposit can be divided into three types: pre-metallogenic hook-like quartz veins, metallogenic auriferous quartz veins, and postmetallogenic N-S quartz veins. Four stages of mineralization in the auriferous quartz veins have been identified:(1) Stage S1 quartz+coarse-grained sulfides,(2) Stage S2 gold+fine-grained sulfides,(3) Stage S3 quartz+carbonates, and(4) Stage S4 quartz+ greigite. Fluid inclusions indicate the oreforming fluid was CO_2-N_2-CH_4 rich with homogenization temperatures of 170–261°C, salinities 4.34–7.45 wt% Na Cl equivalent. δ~(18)Ofluid(3.98‰–7.18‰) and low δDV-SMOW(-90‰ to-44‰) for auriferous quartz veins suggest ore-forming fluids were mainly metamorphic in origin, with some addition of organic matter. Quartz vein pyrite has δ~(34)SV-CDT values of 1.2‰–3.6‰(an average of 2.2‰), whereas pyrite from phyllite has δ~(34)SV-CDT 5.7‰–9.9‰(an average of 7.4‰). Quartz vein pyrites yield 206Pb/204 Pb ratios of 18.662–18.764, 207Pb/204 Pb 15.650–15.683, and ~(208)Pb/204 Pb 38.901–39.079. These isotopic data indicate Bangbu ore-forming materials were probably derived from the Langjiexue accretionary wedge. 40Ar/39 Ar ages for sericite from auriferous sulfide-quartz veins yield a plateau age of 49.52 ± 0.52 Ma, an isochron age of 50.3 ± 0.31 Ma, suggesting that auriferous veins were formed during the main collisional period of the Tibet-Himalayan orogen(~65–41 Ma).
The Bangbu gold deposit is a large orogenic gold deposit in Tibet formed during the Alpine Himalayan collision. Ore bodies (auriferous quartz veins) are controlled by the EW-trending Qusong-Cuogu-Zhemulang brittle-ductile shear zone. Quartz veins at the deposit can be Four stages of mineralization in the auriferous quartz veins have been identified: (1) Stage S1 quartz + coarse-grained sulfides, (2) Stage S2 gold + fine-grained sulfides, (3) Stage S3 quartz + carbonates, and (4) Stage S4 quartz + greigite. Fluid inclusions of the oreforming fluid was CO_2-N_2-CH_4 rich with homogenization temperatures of 170-261 ° C, salinities 4.34-7.45 wt% Na Cl equivalent. Δ ~ (18) Ofluid (3.98 ‰ -7.18 ‰) and low δDV-SMOW (-90 ‰ to-44 ‰) for auriferous quartz veins suggest ore-forming fluids were mainly metamorphic in origin, with some addition of organic mat Quartz vein pyrite has δ ~ (34) SV-CDT values of 1.2 ‰ -3.6 ‰ (an average of 2.2 ‰), while pyrite from phyllite has δ ~ (34) SV-CDT 5.7 ‰ -9.9 ‰ (an average of 7.4 ‰). Quartz vein pyrites yield 206Pb / 204 Pb ratios of 18.662-18.764, 207Pb / 204 Pb 15.650-15.683, and ~ (208) Pb / 204 Pb 38.901-39.079. probably derived from the Langjiexue accretionary wedge. 40Ar / 39 Ar ages for sericite from auriferous sulfide-quartz veins yield a plateau age of 49.52 ± 0.52 Ma, an isochron age of 50.3 ± 0.31 Ma, suggesting that auriferous veins were formed during the main collisional period of the Tibet-Himalayan orogen (~ 65-41 Ma).