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.