A review of W and Sn isotopes and insights into their emerging applications in ore deposit geology

In recent years, the advancements in multi-collector inductively coupled plasma mass spectrometry (MC–ICP–MS) technology have significantly enhanced our understanding of the isotopic variations in tungsten (W) and tin (Sn) among natural samples. The application of W isotopic fractionation (δ^186/184W _{NIST 3163}) has emerged in tracing the material cycle associated with solid Earth evolution as an excellent indicator. Also, the findings of Sn isotopic fractionation (e.g. δ^122/118Sn _3161a) in cassiterite have achieved initial success in revealing magmatic-hydrothermal processes. However, the mechanisms responsible for variations in W and Sn isotopes in the ore-forming processes remain to be fully addressed, and there is an urgent need to apply the W–Sn isotope systematics to geology (especially for ore deposit geology). In this contribution, the high-precision analytical methods for W and Sn isotopes, the significant variability in isotopic compositions, and the immense functionality of the tracing process are systematically summarized and reviewed. Conclusively, the prospects of the application of W and Sn isotopes in geology are listed, and it is pointed out that it is urgent to introduce W–Sn double isotope systematics into the study of ore deposits, apply the stable isotopic method for tracing the source of ore-forming materials and modelling the evolution of W and Sn isotopes in W–Sn metallogenic system. Focusing on the composition variations of W and Sn isotopes in magmatic-hydrothermal evolution is expected to explore the fractionation mechanism of those isotopes in the mineralization process from multiple perspectives, establishing the evolution model of W and Sn isotopes in the complex W–Sn metallogenic system, which can provide a fresh approach for in-depth understanding of the genesis of W–Sn mineralization, and then facilitating a new perspective for the study of large-scale W–Sn polymetallic mineralization.