The age of ductile shear deformation and its constraint on Cu mineralization transformation in Duobaoshan Cu deposit, Heilongjiang Province

The Duobaoshan porphyry Cu deposit is mainly found in Ordovician granodiorite, with minor occurrences in Ordovician granodiorite porphyry and andesite of the Duobaoshan Formation. The copper mineralization is primarily disseminated and levee−disseminated. The metallogenic process encompasses a porphyry stage and a shear deformation stage. A ductile shear deformation zone exists in the mining area, involving the Duobaoshan Formation, granodiorite, granodiorite porphyry, andesitic tuff breccia, and ore bodies. New sericite minerals develop along the shear plane. The plateau age, isochron ages and inverse isochron ages of sericite are 280.1± 1.2 Ma, 281.4 ± 1.3 Ma, and 281.3± 1.3 Ma, respectively, which are consistent within error ranges. The ductile shear deformation occurred during the Early Permian (about 280 Ma). The primary mineralization of the Duobaoshan porphyry copper deposit formed in the Early Ordovician (about 475 Ma). The Early Permian ductile shear deformation reshaped the original copper mineralization, further enriching the copper content and increasing the grade.