Formation of the giant Cretaceous Jiaodong-type orogenic gold province of the North China Craton:A consequence of lithospheric multi-layer reworking

The Cretaceous gold deposits along the margins of the North China Craton (NCC), which formed in a craton destruction setting, display geological characteristics similar to traditional orogenic gold deposits typically associated with accretionary orogeny. These deposits, known as Jiaodong-type gold deposits, have attracted considerable attention. However, the lithospheric controls and formation mechanisms of these deposits remain unclear, as they cannot be fully explained by the supracrustal metamorphic genetic model commonly applied to classic orogenic gold deposits. In this study, the compiled S-Hg-Pb isotope ratios of gold deposits on different NCC margins display compatible variations to the Sr-Nd-Hg isotope ratios of mafic dikes spatial-temporally associated with the deposits. This implies that mantle lithosphere, metasomatized by variable proportions of oceanic and continental crust, was the source for both gold deposits and mafic dikes. Increase of oxygen fugacity and zircon εHf(t) from pre- to syn-gold granites suggests continuous basic magma underplating, which could induce concentrations of Au-rich sulfides and contribute additional Au to auriferous CO₂-rich fluids derived from metasomatized mantle lithosphere and basic magma. Localization of gold deposits was controlled by craton-margin sinistral shearing induced by clockwise rotation of the craton coincident with distal emplacement of metamorphic core complexes. Thus, the Cretaceous Jiaodong-type orogenic gold deposits were derived from fertilized mantle lithosphere through such crust-mantle processes within a lithosphere thinning background.