Mantle-to-crust metal transfer by nanomelts

Abstract The transfer of chalcophile metals across the continental lithosphere has been traditionally modeled based on their chemical equilibrium partitioning in sulfide liquids and silicate magmas. Here, we report a suite Ni-Fe-Cu droplets trans-lithospheric magmatic network linking subcontinental lithospheric mantle to overlying crust. Petrographic characteristics numerical calculations both support that were mechanically scavenged from source during partial melting transported upwards by alkaline magmas rising through lithosphere. Nanoscale investigation high-resolution transmission electron microscopy (HR-TEM) documents presence galena (PbS) nanoinclusions within are involved mantle-to-crust magma route. show range microstructural features inconsistent with derivation PbS exsolution solid products liquid. It is argued crystallized precursor Pb(-Cu)-rich nanomelt, which was originally immiscible liquid even at Pb concentrations largely below those required for attaining saturation. We suggest evidence immiscibility between metal-rich nanomelts transport would disrupt classical way metal flux ore genesis interpreted, hinting mechanical nanophases as key mechanism sourcing amounts mantle-derived can be concentrated