Types, characteristics and metallogenesis of gold deposits in the Jiaodong Peninsula, Eastern North China Craton

Abstract

The Jiaojia type gold deposits in the Jiaodong Peninsula of the North China Craton represent an emerging major gold reserve, and constitute one of the two important types of gold deposits in China, the other being the Linglong type. The gold mineralization in these deposits can be subdivided into seven categories namely, altered-rock type in the fracture zone, gold-bearing quartz vein type, braided quartz vein type along fracture zones, quartz-sulfide vein type, interlayer type along the detachment belt, altered-conglomerate type and breccia type along the basin margin faults. The peak gold mineralization occurred during Early Cretaceous with the metallogeny controlled by extensive crust–mantle interaction. The deposits are hosted in the Early Precambrian basement and Mesozoic intrusions which experienced phyllic, sulfidic, silicic, and potassic alterations. The structures of the ore bodies include pinchout, repetition splay branches, composite, lateral tilting, echelon and imbrications. The upwelling of hot magma, fluid activity and extensional detachment resulted in the formation of extensive gold deposits in the Jiaodong Peninsula. The extensional detachment derived from magma upwelling provided favorable ore-hosting structure for the gold deposition. The ladder-type ore-hosting structures show variation from sharp to gentle dips with marked enrichment of the gold ores at the gentle angle of the fault segments and at the transition from steep to gentle dip angles, displaying a step-fault-controlled ore deposition. The formation of the gold deposits in the Jiaodong Peninsula coincided with the large-scale Early Cretaceous thinning of the lithosphere in the North China Craton, mainly controlled by extensional tectonics.