Mantle sources of the Cenozoic volcanic rocks of East Asia: Derivatives of slabs,the sublithospheric convection,and the lithosphere

The spatial-temporal variations of the trace element and Sr isotope composition were analyzed in the Middle-Late Cenozoic volcanic rocks of the East Asian continental margin. The heterogeneity of the sublithospheric mantle was characterized, the active sources of the supraslab mantle were distinguished, and the Southern and Northern sublithospheric convective subdomains of the Transbaikalian low-velocity domain at a depth of 410–200 km were distinguished. The supply of isotopically homogenous mantle from the convective subdomains was replaced in space and time by their mixtures. Isotopically highly depleted material was derived from the mantle above the Kula-Izanagi and Pacific slabs ～43.5, 23–17, and <15 Ma, while moderately depleted mantle was derived from the Northern and Southern subdomains ～37, 31–23, and ～16 Ma and 19–12 Ma, respectively. Similar convective but shallower isotopically enriched material was determined in mixtures from the Southern convective subdomain in the Northeast Japanese arc within 30–9 Ma and in mixtures with isotopically enriched lithospheric mantle in the central Heilongjiang Province <9.6 Ma. Lithospheric melts erupted during drastic changes in the dynamics of the sublithospheric convective subdomains.