Tectonic–geodynamic settings of OIB-magmatism on the eastern Asian continental margin during the Cretaceous–Paleogene transition

Abstract

At the Cretaceous–Paleogene transition, the convergent boundary between the Asian and Pacific plates was replaced by a transform boundary to determine destruction of the continental margin including the Okhotsk–Chukotka Cretaceous subduction-related belt along left-lateral strike-slip and downdip–strikeslip faults. The newly formed East Asian rift system (EARS) continues in the easterly direction the Mongol–Okhotsk zone of left-lateral strike-slip faults, a former transform boundary of the Asian continent. Basaltoids of the East Asian rift system that erupted through fractures onto the former active margin are similar intraplate OIB volcanics related to the lower mantle source. The specific feature of OIB-type magmatism in the system consists in its continental marginal position near the transform boundary.