The discovery of Late Carboniferous hydrothermal cherts in the Longyan area of the Wuyishan metallogenic belt and its geological implications

Multiple submarine volcanic mineralization formations developed in the Wuyishan metallogenic belt have received much concern in recent years’ mineral exploration. Based on the geological characteristics of the lead-zinc mineralized breccia layer of Late Carboniferous Jingshe Formation in the Longyan area, petrographical and lithogeochemical studies of cherts from the breccia layer have been carried out in order to understand element(Zn and Pb)sources and enrichment mechanism. The research suggests that cherts have negative correlation between SiO₂ and Al₂O₃, with most Fe₂O₃/FeO ratios less than 1 and positive Eu anomaly, which indicates a hydrothermal sedimentary genesis for cherts. The cherts have Al₂O₃/(Al₂O₃+TFe₂O₃)values of 0.73～0.80(averaging 0.77), Al₂O₃/(Al₂O₃+TFe₂O₃+MnO)of 0.60～0.65(averaging 0.62), and La_N/Ce_N of 0.86～2.49(averaging 1.52), which show that the cherts were influenced by continential materials. Finally, it can be concluded that the lead-zinc mineralized breccia layer of Late Carboniferous Jingshe Formation was the product of hydrothermal vent collapse on the seafloor. This study has significant implications for guiding mineral exploration in the Wuyishan metallogenic belt.