Comparison of gold mineralization between the Jiaodong and Liaodong Peninsulas: Perspectives from geochronology, fluid inclusions and isotopic signatures

This paper is the result of mineral exploration engineering.

Objective The Jiaodong and Liaodong Peninsulas share similar geological backgrounds for gold mineralization, and there are many similarities between the Jiaodong and Liaodong gold deposits. However, the currently known gold endowment of the Liaodong gold deposit is significantly lower than that of the Jiaodong gold deposit.

Methods In this study, we systematically collected the age of gold mineralization, fluid inclusions, and H–O–S–Pb–He–Ar isotopes data from the Liaodong gold deposits. Through taking the data of the Jiaodong gold deposits by previous reseachers as background values, we conducted a comparative study of gold mineralization between the Jiaodong and Liaodong peninsulas.

Results The mineralization age of the Jiaodong gold deposits is mainly clustered at ~120 Ma. The time covers the periods from Paleoproterozoic, Triassic, Early Jurassic, to Early Cretaceous, with Early Cretaceous being major period of gold mineralization in the Liaodong. The ore-forming fluids of the Jiaodong and Liaodong gold deposits are both medium temperatures, and medium to low salinity CO₂–H₂O–NaCl hydrothermal fluid systems. Fluid immiscibility and fluid mixing are key mechanisms for gold precipitation. Among them, the Liaodong altered-rock type gold deposits markedly have high to medium temperature, and high to medium salinity magmatic-hydrothermal fluids. The ore-forming fluids of the Jiaodong and Liaodong gold deposits were a mixture of crustal-derived and mantle-derived fluids. However, the contribution of mantle-derived fluids to the Jiaodong is prominently greater than that to the Liaodong. In addition, the Archean Jiaodong Group and Paleoproterozoic Gaixian Formation of Liaohe Group have made great contributions to the gold mineralization in the Jiaodong and Liaodong, respectively, with the Archean Anshan Group contributing less to the Liaodong gold mineralization.

Conclusions Compared to the Jiaodong, the unsatisfactory prospecting results in the Liaodong Peninsula may be attributed to the complexity of mineralization and potential differences in ore-controlling structures. Strengthening the study on multistage superimposed metallogeny and ore-controlling structures in the Liaodong Peninsula, especially focusing on high−angle normal faults and low−angle bedding extension and sliding fractured zones, is expected to achieve breakthroughs in gold exploration in Liaodong.