Multi-episodic mantle upwelling overprinting drives the formation of large to giant porphyry Cu-Au deposits

• Multiple mantle upwelling occurred in the mid-west Bangong-Nujiang metallogenic belt. • Multiple mantle upwelling occurred from Mid–Late Jurassic to Early Cretaceous. • Multiple mantle upwelling overprinting is key to forming giant porphyry deposits. The world’s most significant sources of copper and gold are large-to-giant porphyry Cu–Au deposits; however, the tectonic setting and mechanisms responsible for these abnormal Cu–Au enrichments are controversial, which restricted our in-depth research on Cu–Au mineralization and prospecting. The central‐western segment of the Bangong–Nujiang metallogenic belt (BNMB) contains regions with world-class porphyry Cu–Au enrichments, with deposits spanning various scales. The spatiotemporal coupling between magmatism and mineralization in this region provides critical insights into the tectonic drivers of metal super-enrichment in giant porphyry systems. This study conducted systematic petrographic, geochronological, geochemical, and Sr-Nd-Hf isotopic analyses for the Middle-Late Jurassic igneous rocks, and comprehensively analyzed spatial–temporal relationship between Late Mesozoic magmatic events and Cu-Au deposit distribution on Central Tibet. Our results indicate that the central-western BNMB experienced multi-episodic mantle-derived magmatic upwelling events during the Late Mesozoic, which all contributing to Cu-Au pre-enrichment. Medium- and small-scale Cu–Au deposits are primarily associated with single-phase mantle upwelling zones, whereas large– to giant-scale porphyry Cu–Au deposits are concentrated in areas where the effects of multiple mantle upwelling events are superimposed. Based on these spatial–temporal correlations and analogous records of multiple mantle upwelling episodes documented in other typical large– to giant-scale deposits worldwide, we propose that multi-episodic mantle upwelling overprinting is a critical prerequisite for the formation of giant porphyry Cu-Au deposits.