The sources of metallogenic materials and mineralization of the Xiaoyao Wpolymetallic deposit in Anhui Province: Evidence from carbon, sulfur and lead isotopes

The Xiaoyao W-polymetallic deposit of Anhui Province is a W-Ag-Zn-Pb-Cu-Mo deposit in Jiangnan uplift.The W-polymetallic ore bodies mainly occur as lenses,layers and veins in the contact zone between the intrusion and the wall rock.The δ13C characteristics of calcite in this deposit suggest that the carbon was mainly derived from magmatic rocks with a certain amount from the country rocks through the leaching of groundwater derived from meteoric waters.The δ34SV-CDT values suggest that sulfur isotopes in pyrrhotine,pyrite,chalcopyrite have not reached equilibrium.Sulfur was mainly derived from magmatic rocks,contaminated by the country rocks during the metallogenic process.The tectonic patterns of lead isotope and related parameters indicate that the metallogenic material was closely related to magmatism.The lead generally came from the lower crust and was characterized by the mixture of the crust and the mantle.Based on the features of carbon,sulfur and lead isotopes of the W-polymetallic deposit,the authors have concluded that the large-scale Yanshanian tectonic-magmatic activity not only brought a large amount of metallogenic materials for the deposit but also promoted the activation and migration of metallogenic materials from the strata.These materials were precipitated and concentrated in some favorable structures and formed the W-polymetallic deposit.