Trace element and helium isotope geochemistry of the Cenozoic intraplate volcanism in the East Sea (Sea of Japan): Implications for lithosphere-asthenosphere interaction

Extensive intraplate volcanism in the East Asia regions, including Dokdo and Ulleungdo (DU), occurred due to extensional stress field during Cenozoic era. However, origin of magmatism is still controversial. Here we report new results helium isotopes olivine clinopyroxene phenocrysts as well major trace element compositions from DU basalts order determine magmas provide insights into mantle dynamics Asia. The volcanic islands were formed by after opening Sea (Sea Japan), a back-arc basin behind Japanese arc, are currently located Ulleung basin, one sub-basins Sea. 3 He/ 4 He ratios range 5.7 5.9 Ra for 4.5 6.0 Ulleungdo, respectively, similar sub-continental lithospheric (SCLM) (4.6 7.7 Ra). Helium isotope indicate that depleted asthenosphere or lower plume might not be direct source magmas. Also, there no geochemical evidence influenced subduction-derived components HIMU source. Hence, argue SCLM provided enriched features basalts, contrary other basins composed oceanic crust. In this respect, it likely extended may remain beneath basin. Our mixing model shows trend between metasomatized melts asthenospheric melts. addition, presence low-velocity zone surface volcanoes seismic tomography implies through melting hot upwelling. Therefore, our study was mainly contributed lithosphere-asthenosphere interaction main mechanism led • Dokdo-Ulleungdo significantly SCLM. Lithosphere-asthenosphere played pivotal role magmatism.