Zircon as a pathfinder for ore exploration

Abstract

Despite its wide application in dating geological events like magmatism, diagenesis, and metamorphic processes, zircon morphological, geochronological, and geochemical implications in ore systems have hitherto received little attention. In this study, we used textural, chemical, and isotopic data of zircons from variable granite-related deposits and other deposit types to emphasize zircon robustness as a pathfinder for ore exploration. The results show that zircons from W–Sn-related granites are rich in U, P, Ti, Y, Nb, Ta, Pb, Hf, Th, and REE compared to Cu–Mo-related granite. For the vein-type deposits, ore-bearing veins have significant zircons captured from geological bodies through which ore-forming fluid originated and migrated (e.g., basement rocks), whereas ore-free veins possess fewer zircons and are mostly from country rocks. Finally, in skarn-type deposits, ore-bearing skarns have zircons from granitic rocks and country rocks, whereas ore-free skarns have zircons only from one end member, either from granitic rocks or from country rocks. The variability in zircon abundance in these deposit types results from differences in the degree of magmatic differentiation of granitic rocks, variable zircon incorporation processes during veining and degree of contact-metasomatism during skarnization. We proposed a series of diagrams and employed partial least square discrimination analysis (PLS-DA) to differentiate the metallogenetic potential of granite-related, vein-type, and skarn-type deposits. The zircon criteria summarized by this study can be applied to similar ore deposits worldwide, which are significant for exploring economic minerals.