AbstractDuring the late Cenozoic, the extensional tectonic setting in northeastern China caused large-scale block uplifts and depressions, and thus a large amount of magma erupted along structural fractures in the eastern Inner Mongolia, NE China. The Abaga, Beilike, Dalinor and Wulanhada (ABDW) volcanic rocks along the Daxing'anling-Taihangshan Gravity Lineament in the southern section of the Daxing'anling are characterized by their extensive distribution, numerous volcanic cones and various eruption types. Each volcanic group has distinctive volcanic landforms and geochemical characteristics. The geochronological data have revealed that the volcanism spanned Miocene to late Pleistocene. The ABDW volcanic rocks contain primary alkaline basalts and subordinate tholeiites. The trace element curve pattern is similar to that of OIB, but completely different from that of MORB, while the LREE are more enriched than HREE. The geochemical features of the volcanic rocks and the entrained mantle xenoliths reveal the broad heterogeneities of the lithospheric mantle and varieties of the volcanic rock evolution in the south Daxing'anling. The Cenozoic volcanism in eastern Inner Mongolia, and even within the east Asian plate, is attributed to the westward subduction and rolling backward of the Pacific slab as well as the trench retreat.
