南秦岭柞水-山阳矿集区金盆梁金矿床成因OA北大核心CSTPCD

The Jinpenliang is an explored micro-disseminated gold deposit in the Zhashui-Shanyang ore cluster area,South Qinling. To date,its ore genesis and metallogenic mechanism are still unclear. These Au-Sb orebodies at Jinpenliang deposit are hosted by the silty slate and calcareous slate of the Upper Devonian Tongyusi Formation,occurring as disseminated and veinlet mineralization. The ore-forming process can be classified into three stages,namely,arsenopyrite-pyrite-silicification stage ( Ⅰ ),quartz-stibnite-marcasite±antimony oxide stage (Ⅱ),and cal-cite-quartz stage ( Ⅲ ). Fluid inclusion and C-H-O-S-Pb isotope studies indicate that inclusions in stage Ⅱ quartz(Au and Sb mineralization) are dominated by the H2O-NaCl two-phase inclusions. The metallogenic fluid is char-acterized by a medium-temperature (200～290℃),low-salinity (w(NaCleq)=0～6.0％),and low-density (0.64～0.99 g/cm3) H2O-NaCl±CO2 system,predominately originated from meteoric water. Besides the H2O-NaCl two-phase inclusions,there are a small amount of CO2-H2O-NaCl±CH4 inclusions,pure CO2±CH4 inclusions,and daughter mineral-bearing multiphase inclusions identified in quartz of stage Ⅲ barren veins. This nonmetallogenic fluid primarily belongs to a medium to low-temperature (140～280℃),low-salinity (w(NaCleq) 2.0％～8.0％),and low-density (0.68～1.02 g/cm3) CO2-H2O-NaCl±CH4 system,with a high-temperature,high-salinity,and high-den-sity H2O-NaCl system of magmatic water mixed in. The δ34S values of sulfides range from-12.50‰ to-10.20‰,and the Pb isotopic compositions have the characteristics of the upper crust,implying that the ore-froming materials were mainly derived from wall rocks. Comprehensive studies show that the Jinpenliang deposit can be classed as a typical Carlin-type gold deposit,and the water-rock reaction (sulfidation) is the crucial mechanism for gold pre-cipitation.