Ore potential of the Meso- and Cenoproterozoic Dongyan Formation in central Fujian

Abstract：Metamorphic rocks of the Meso- and Cenoproterozoic Dongyan Formation in central Fujian are an important source bed of lead-zinc polymetallic deposits. The metamorphic rocks consist of three basic-acid volcanic-sedimentary cycles and show the features of bimodal volcanic rocks. Each volcanic cycle starts with basic rocks and ends with acid rocks, and marine carbonate rocks often occurred during dormant periods, especially at ｔｈｅ end of each cycle. Lead-zinc-silver deposits are usually associated with basic volcanic rocks. Petrological and chemical analyses of the metamorphic rocks of the Dongyan Formation reveal that the protoliths of the metamorphic rocks of the formation have the features of continental rift tholeiite and formed in an intraplate rift environment. The tectonic setting should be the extensional environment in the interior of the continental plate.