LAUSR

Abstract The Kangshan Au-polymetallic deposit, in the Xiong’ershan District of China, lies on the southern margin of the North China Craton. The orebodies are hosted in (E)NE–(W)SW-trending brittle faults formed during the Mesozoic, which crosscut Neoarchean metamorphic rocks and Mesoproterozoic volcanic rocks. The ore-forming process can be divided into three stages: a quartz ± pyrite stage (Stage 1), a quartz-polymetallic sulfide stage (Stage 2), and a quartz-calcite stage (Stage 3). Stage 2 includes two substages: a quartz-pyrite-chalcopyrite-electrum substage (Stage 2-1; the main Au mineralization stage) and a galena-sphalerite-pyrite-ankerite-Ag-bearing tetrahedrite ± chalcopyrite ± electrum substage (Stage 2-2; the main Pb-Zn-Ag mineralization stage). Four types of fluid inclusions have been identified in the Kangshan deposit: three-phase CO2-rich inclusions, two-phase aqueous inclusions, one-phase vapor inclusions and one-phase aqueous inclusions. Inclusion microthermometric, laser Raman, and C-H-O-S-Pb isotope analyses were undertaken to clarify the properties of the ore-forming fluids, sources of these fluids and ore-forming materials, and mineral precipitation mechanisms. Laser Raman spectroscopic analysis indicate that the ore-forming fluids were formed in a NaCl-H2O-CO2 system. Inclusion homogenization temperatures and salinities are 130 °C–359 °C, and 0.53–11.46 wt% NaCl equivalent (eqv.), respectively. δ18Ofluid values calculated from the δ18OSMOW and δD values of the inclusions in auriferous quartz veins are 1.0–9.0‰ and -92‰ to -67‰, respectively. δ13CPDB and δ18OSMOW values of ankerite are -4.89‰ to -3.67‰ and 12.0‰–13.9‰, respectively. Fluid C-H-O isotopic compositions indicate that the ore-forming fluids originated mainly from magmas, with minor addition of meteoric water. δ34S values of the ore sulfides are 4.8‰–7.4‰; 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb ratios of the ore sulfides are 17.625–17.889, 15.543–15.620, and 38.389–38.740, respectively. S-Pb isotopic compositions indicate that the ore-forming materials of the deposit originated from granitic magmas and host rocks. The Kangshan Au-polymetallic deposit is a medium–low-temperature hydrothermal deposit. Its mineralization may be related toEarly Cretaceous granite formed in an extensional tectonic setting caused by craton destruction on the southern margin of the North China Craton.