The Xiaguan Ag-Pb-Zn orefield (Neixiang County, Henan Province), hosting the Yindonggou, Zhouzhuang, Yinhulugou and Laozhuang fault-controlled lode deposits, is situated in the Erlangping Terrane, eastern Qinling Orogen. The quartz-sulfide vein mineralization is dominated by main alteration styles of silicic-, sericite-, carbonate-, chlorite- and sulfide alteration. Major Ag-bearing minerals are freibergite, argentite and native Ag. The deposits were formed by a CO2-rich, mesothermal (ca. 250-320 degrees C), low-density and low salinity (< 11 wt.% NaCl equiv.), Na+-Cl--type fluid system. Trapping pressures of the carbonic-type fluid inclusions (FIs) decreased from ca. 280-320 MPa in the early mineralization stage to ca. 90-92 MPa in the late mineralization stage, indicating that the ore-forming depths had become progressively shallower. This further suggests that the metallogenesis may have occurred in a tectonic transition from compression to extension. Geological- and ore fluid characteristics suggest that the Xiaguan Ag-Pb-Zn orefield belongs to orogenic-type systems. The delta O-18(H2O) values change from the Early (E)-stage (7.8-10.8 parts per thousand), through Middle (M)-stage (6.0-9.4 parts per thousand) to Late (L)-stage (-1.5-3.3 parts per thousand), with delta D values changing from E-stage -95 to -46 parts per thousand, through M-stage -82 to - 70 parts per thousand to L-stage -95 to - 82 parts per thousand. d13CCO2 values of the ore fluids in the E- and M-stage quartz vary between 0.1 parts per thousand and 0.9 parts per thousand (average: 0.3 parts per thousand ); delta O-18(H2O) values of L-stage FIs are -0.2-0.1 parts per thousand in quartz and -6.8 parts per thousand to - 3.5 parts per thousand in calcite. The H-O-C isotopic data indicate that the initial ore fluids were sourced from the underthrusted Qinling Group marine carbonates, and were then interacted with the ore-hosting Erlangping Group metasedimentary rocks. Inflow of circulated meteoric water may have dominated the L-stage fluid evolution. Sulfur (delta S-34 = 1.9-8.1 parts per thousand) and lead isotopic compositions (Pb-206/Pb-204 = 18.202-18.446, Pb-207/Pb-204 = 15.567-15.773 and Pb-208/Pb-204 = 38.491-39.089) of sulfides suggest that the ore-forming materials were mainly sourced from the ore-hosting metasedimentary strata. The stepped heating sericite 40Ar/39Ar detection suggests that the mineralization occurred in the Middle Jurassic to Early Cretaceous (ca. 187 - 124 Ma). Considering the regional tectonic evolution of the Erlangping Terrane, we propose that the Xiaguan Ag-Pb-Zn orefield was formed in a continent-continent collisional tectonic regime, in accordance with the tectonic model for continental collision, metallogeny and fluid flow (CMF). (C) 2016 Elsevier B.V. All rights reserved. The Xiaguan Ag-Pb-Zn orefield (Neixiang County, Henan Province), hosting the Yindonggou, Zhouzhuang, Yinhulugou and Laozhuang fault-controlled lode deposits, is situated in the Erlangping Terrane, eastern Qinling Orogen. The quartz-sulfide vein mineralization is dominated by main alteration styles of silicic-, sericite-, carbonate-, chlorite- and sulfide alteration. Major Ag-bearing minerals are freibergite, argentite and native Ag. The deposits were formed by a CO2-rich, mesothermal (ca. 250-320 degrees C), low-density and low salinity (< 11 wt.% NaCl equiv.), Na+-Cl--type fluid system. Trapping pressures of the carbonic-type fluid inclusions (FIs) decreased from ca. 280-320 MPa in the early mineralization stage to ca. 90-92 MPa in the late mineralization stage, indicating that the ore-forming depths had become progressively shallower. This further suggests that the metallogenesis may have occurred in a tectonic transition from compression to extension. Geological- and ore fluid characteristics suggest that the Xiaguan Ag-Pb-Zn orefield belongs to orogenic-type systems. The delta O-18(H2O) values change from the Early (E)-stage (7.8-10.8 parts per thousand), through Middle (M)-stage (6.0-9.4 parts per thousand) to Late (L)-stage (-1.5-3.3 parts per thousand), with delta D values changing from E-stage -95 to -46 parts per thousand, through M-stage -82 to - 70 parts per thousand to L-stage -95 to - 82 parts per thousand. d13CCO2 values of the ore fluids in the E- and M-stage quartz vary between 0.1 parts per thousand and 0.9 parts per thousand (average: 0.3 parts per thousand ); delta O-18(H2O) values of L-stage FIs are -0.2-0.1 parts per thousand in quartz and -6.8 parts per thousand to - 3.5 parts per thousand in calcite. The H-O-C isotopic data indicate that the initial ore fluids were sourced from the underthrusted Qinling Group marine carbonates, and were then interacted with the ore-hosting Erlangping Group metasedimentary rocks. Inflow of circulated meteoric water may have dominated the L-stage fluid evolution. Sulfur (delta S-34 = 1.9-8.1 parts per thousand) and lead isotopic compositions (Pb-206/Pb-204 = 18.202-18.446, Pb-207/Pb-204 = 15.567-15.773 and Pb-208/Pb-204 = 38.491-39.089) of sulfides suggest that the ore-forming materials were mainly sourced from the ore-hosting metasedimentary strata. The stepped heating sericite 40Ar/39Ar detection suggests that the mineralization occurred in the Middle Jurassic to Early Cretaceous (ca. 187 - 124 Ma). Considering the regional tectonic evolution of the Erlangping Terrane, we propose that the Xiaguan Ag-Pb-Zn orefield was formed in a continent-continent collisional tectonic regime, in accordance with the tectonic model for continental collision, metallogeny and fluid flow (CMF). (C) 2016 Elsevier B.V. All rights reserved. The Xiaguan Ag-Pb-Zn orefield (Neixiang County, Henan Province), hosting the Yindonggou, Zhouzhuang, Yinhulugou and Laozhuang fault-controlled lode deposits, is situated in the Erlangping Terrane, eastern Qinling Orogen. The quartz-sulfide vein mineralization is dominated by main alteration styles of silicic-, sericite-, carbonate-, chlorite- and sulfide alteration. Major Ag-bearing minerals are freibergite, argentite and native Ag. The deposits were formed by a CO2-rich, mesothermal (ca. 250-320 degrees C), low-density and low salinity (< 11 wt.% NaCl equiv.), Na+-Cl--type fluid system. Trapping pressures of the carbonic-type fluid inclusions (FIs) decreased from ca. 280-320 MPa in the early mineralization stage to ca. 90-92 MPa in the late mineralization stage, indicating that the ore-forming depths had become progressively shallower. This further suggests that the metallogenesis may have occurred in a tectonic transition from compression to extension. Geological- and ore fluid characteristics suggest that the Xiaguan Ag-Pb-Zn orefield belongs to orogenic-type systems. The delta O-18(H2O) values change from the Early (E)-stage (7.8-10.8 parts per thousand), through Middle (M)-stage (6.0-9.4 parts per thousand) to Late (L)-stage (-1.5-3.3 parts per thousand), with delta D values changing from E-stage -95 to -46 parts per thousand, through M-stage -82 to - 70 parts per thousand to L-stage -95 to - 82 parts per thousand. d13CCO2 values of the ore fluids in the E- and M-stage quartz vary between 0.1 parts per thousand and 0.9 parts per thousand (average: 0.3 parts per thousand ); delta O-18(H2O) values of L-stage FIs are -0.2-0.1 parts per thousand in quartz and -6.8 parts per thousand to - 3.5 parts per thousand in calcite. The H-O-C isotopic data indicate that the initial ore fluids were sourced from the underthrusted Qinling Group marine carbonates, and were then interacted with the ore-hosting Erlangping Group metasedimentary rocks. Inflow of circulated meteoric water may have dominated the L-stage fluid evolution. Sulfur (delta S-34 = 1.9-8.1 parts per thousand) and lead isotopic compositions (Pb-206/Pb-204 = 18.202-18.446, Pb-207/Pb-204 = 15.567-15.773 and Pb-208/Pb-204 = 38.491-39.089) of sulfides suggest that the ore-forming materials were mainly sourced from the ore-hosting metasedimentary strata. The stepped heating sericite 40Ar/39Ar detection suggests that the mineralization occurred in the Middle Jurassic to Early Cretaceous (ca. 187 - 124 Ma). Considering the regional tectonic evolution of the Erlangping Terrane, we propose that the Xiaguan Ag-Pb-Zn orefield was formed in a continent-continent collisional tectonic regime, in accordance with the tectonic model for continental collision, metallogeny and fluid flow (CMF). (C) 2016 Elsevier B.V. All rights reserved.
