Petrogenesis of the ca. 2.32 Ga low-δ18O gabbroic diorites and granites in the Xiaoshan area, southern North China Craton: Implications for the early Paleoproterozoic tectonic evolution

•The low-δ18O gabbroic diorites and granites in the Xiaoshan area were formed at ∼ 2.32 Ga.•The gabbroic diorites were derived from partial melting of metasomatized continental lithospheric mantle source.•The granites were derived from partial melting of pre-existing lower crust.•Extension-related tectonic regime is reasonable in the early Paleoproterozoic Era, at least for the southern NCC.