A subduction distance control on craton-margin metallogenesis

Craton margins represent long-lived lithospheric weak zones that host a disproportionate share of the world’s sediment-hosted Pb–Zn and Cu resources, yet the geodynamic conditions that distinguish fertile from barren margins remain poorly constrained. Here, we test the hypothesis that subduction dynamics exert a first-order control on craton-margin metallogenesis by integrating a 1.8-billion-year global plate motion model, machine learning–derived craton boundary mapping from full-waveform seismic tomography, a global database of age-coded sediment-hosted deposits, and numerical geodynamic simulations.

Spatiotemporal analysis reveals that mineralised craton margins systematically cluster within 2000 km from active subduction trenches at the time of deposit formation—a spatial signal absent from 90,000 randomly generated craton-margin locations propagated through deep time. More than 90% of the total contained metal endowment of the analysed deposits lies within this 2000 km threshold, demonstrating that trench proximity is a robust discriminator between fertile and barren craton edges. This relationship is consistent across three supercontinent cycles and multiple deposit types, including Pb–Zn clastic-dominated, Mississippi Valley–type, and sediment-hosted Cu systems. Kinematic analysis further shows that deposits formed preferentially during episodes of moderate trench retreat, indicating that the overriding plate migrates oceanward and repositions cratons over previously subducted domains.

Numerical geodynamic models reproduce a comparable spatial scale, with subduction-driven mantle return flow generating lithospheric strain-rate maxima at craton margins approximately 2000 km from trenches. These results indicate that subduction transmits stresses thousands of kilometres into the overriding plate, localising deformation at craton edges while preserving craton interiors. There is a slight offset between observed deposit clustering and modelled strain peaks, likely reflecting inherited lithospheric heterogeneity and three-dimensional mantle flow effects not captured by simplified two-dimensional models. Strain localisation enhances permeability, facilitating long-term metasomatic enrichment of the subcontinental lithospheric mantle by slab-derived fluids.

Subduction-derived volatiles and ligands—including halogens, carbon, and reduced sulphur—play a critical role in metallogenic fertility by increasing the capacity of basinal brines to dissolve, transport, and precipitate metals. Episodes of trench retreat position cratons over previously enriched mantle domains, promoting the ascent of metal-bearing fluids and partial melts into sedimentary basins and triggering short-lived mineralisation events. This mechanism provides a physical explanation for the temporal clustering of giant sediment-hosted deposits during supercontinent breakup phases, when rollback-driven extension and back-arc processes were widespread.

Together, the convergence of global reconstructions, statistical analyses, and geodynamic modelling demonstrates that subduction is a fundamental driver of craton-margin metallogenesis. By quantifying a predictive distance window linking subduction, mantle flow, and lithospheric weakening, this study provides a physically grounded framework for mineral exploration and reveals how deep-Earth dynamics regulate the long-term distribution of critical metal resources throughout Earth history.