Lead isotope composition of the Jiashengpan lead-zinc-sulfur deposit in Inner Mongolia and its tracing significance for ore-forming materials

Abstract：The Jiashengpan lead-zinc-sulfur deposit is located in the Langshan-Zhaertaishan mineralization belt on the northern margin of the North China Platform. Its ore bodies are hosted in black shale strata of the Mesoproterozoic Zhaertaishan Group. Lead isotopic composition of sulfides in ores can be classified into two groups (Group A and Group B). Group A is characterized by lower radiogenic lead with 206Pb/204Pb ranging from 15.889 to 16.257, 207Pb/204Pb ranging from 15.158 to 15.455, and 208Pb/204Pb ranging from 35.112 to 36.271, whereas Group B is characterized by higher radiogenic lead with 206Pb/204Pb ranging from 17.871 to 18.990, 207Pb/204Pb ranging from 15.509 to 15.672, and 208Pb/204Pb ranging from 37.525 to 38.770. It is evident that the sulfides in ores can be divided into the early depositional ones having fine-grained, layered and disseminated features and the later ones having coarse-grained and veinlike features. Both of them contain lead isotope compositions of Group A and Group B, but the former consists mainly of the features of Group A whereas the latter consists mainly of the features of Group B. Based on tectonic patterns of lead isotope and related parameters, it can be concluded that the lead of Group A was mainly derived from the upper crust and the orogenic belt with the participation of some mantle-derived lead. The ore-forming materials of Group A were derived from the old basement strata during the main ore-forming period, whereas the lead of Group B was mainly derived from the late hydrothermal event with some influence of the Varisian granite to the north of the ore bodies. The lead of the Jiashengpan ore deposit has a multi-source mixing structure.