Radiogenic Isotope Studies of Late Cenozoic Volcanic Rocks from Asia and North America: Sources of Volcanism of Global, Regional, and Local Significance

Abstract

Of global importance are sources of Late Cenozoic volcanic rocks, indicated by fast and slow anomalies of the lower mantle: ASITA, SOPITA, AFITA, and NAITA. ASITA characterizes the LOMU–ELMU protomantle melt anomalies of the lower mantle high velocity skeleton of Asia during the early mantle geodynamic epoch. SOPITA and AFITA are marked by the HIMU plume component, which was generated in the low-velocity lower mantle of the South Pacific and Africa during the middle mantle geodynamic epoch, about 2 Ga. NAITA denotes processes of generation of the North American high-velocity lower-mantle anomaly in the late geodynamic epoch. Of regional importance are sub-lithospheric sources that are characterized by a common geochemical structure of volcanic rocks of large volcanic regions, formed due to the evolution of homogeneous proto-mantle deep reservoirs. An example is sources of the Wulanhada-Hannuoba and Abaga-Dariganga volcanic regions, marking the spatial transition from the LOMU proto-mantle reservoir of the former to the ELMU one of the latter. Local sources of volcanoes are displayed in limited volumes of melts from the heterogeneous lithosphere. An example is sources of the Wudalianchi volcanic field, on which, at first, in the time interval of 2.5–0.8 Ma, the material of the Laoshantou and Gelaqiu sources with a common age of 1.88 Ga occurred, and then, during the spatial-temporal evolution of volcanism in the last 0.6 Ma, the material from these sources was mixed with a younger lithospheric material.