摘要
The Binh Do Pb-Zn deposit in the Phu Luong region(Thai Nguyen Province,northern Vietnam)is located on the southern margin of the South China Block.The fault-controlled Pb-Zn orebodies are mainly hosted in Upper Paleozoic carbonate formations.In order to reveal the mineralization type and metallogenesis of this deposit,multi-isotopic(S,Pb,H and O)analyses on typical ore and gangue minerals were conducted.The average ore sulfide δ^34 S∑S value is 4.3‰,suggestive of magmatic sulfur.The ore sulfide Pb isotope compositions are homogeneous,with the 206 Pb^204 Pb,207 Pb^204 Pb and 208 Pb^204 Pb values of 18.501 to 18.673,15.707 to 15.798,and 38.911 to 39.428,respectively.Lead isotope model ages of the ore sulfides(240-220 Ma)are consistent with the timing of regional Triassic S-type granite emplacement(250-220 Ma),suggesting that the metals may have been granite-derived.The quartz δDV-SMOW(-82.4‰ to-70.5‰)and δ^18 OH2 O(-0.4‰ to +6.4‰)values suggest that the ore-forming fluids were composed of mixed magmatic and meteoric waters.Combined with the geological features of the Pb-Zn deposit in the region,we propose that the Pb-Zn deposits belong to magmatic-hydrothermal type,rather than MVT-type as previously suggested.The Triassic granites may have contributed the ore-forming material and heat that drove the hydrothermal system.The ore-forming fluids may have migrated into interlayer faults and fractures of the carbonate strata,diluted by subsurface meteoric water and deposited successively the vein-type and stratiform-type Pb-Zn ores.
The Binh Do Pb-Zn deposit in the Phu Luong region（Thai Nguyen Province,northern Vietnam）is located on the southern margin of the South China Block.The fault-controlled Pb-Zn orebodies are mainly hosted in Upper Paleozoic carbonate formations.In order to reveal the mineralization type and metallogenesis of this deposit,multi-isotopic（S, Pb, H and O）analyses on typical ore and gangue minerals were conducted.The average ore sulfide δ34 S∑S value is 4.3‰, suggestive of magmatic sulfur.The ore sulfide Pb isotope compositions are homogeneous,with the 206 Pb/204 Pb,207 Pb/204 Pb and 208 Pb/204 Pb values of 18.501 to 18.673,15.707 to 15.798,and 38.911 to 39.428,respectively.Lead isotope model ages of the ore sulfides（240-220 Ma）are consistent with the timing of regional Triassic S-type granite emplacement（250-220 Ma）,suggesting that the metals may have been granite-derived.The quartz δDV-SMOW（-82.4‰ to-70.5‰）and δ18 OH2 O（-0.4‰ to +6.4‰）values suggest that the ore-forming fluids were composed of mixed magmatic and meteoric waters.Combined with the geological features of the Pb-Zn deposit in the region,we propose that the Pb-Zn deposits belong to magmatic-hydrothermal type,rather than MVT-type as previously suggested.The Triassic granites may have contributed the ore-forming material and heat that drove the hydrothermal system.The ore-forming fluids may have migrated into interlayer faults and fractures of the carbonate strata,diluted by subsurface meteoric water and deposited successively the vein-type and stratiform-type Pb-Zn ores.
基金
partially financed by the National Natural Science Foundation of China (No. 41502067)
