Ages of the Proterozoic strata in Fanhe Basin revisited: Implications for geological records of the Great Oxidation Event in the North China Craton

•A dolerite sill emplaced into the Guanmenshan Formation was dated at ca. 2060 Ma.•The lower part of Fanhe Group was deposited in the span of 2200–2060 Ma in the Rhyacian Period.•The lower part of Fanhe Group provides excellent stratigraphic records of the GOE and LJE in the NCC.