Composition and Sources of Volcanic Rocks of the Dariganga Plateau: An Assessment of the Formation Mechanisms of the Late Cenozoic Intraplate Volcanic Province of Central and East Asia

Abstract

New data are presented on the petrochemical, geochemical, and isotopic (Sr, Nd, and Pb) characteristics of volcanic rocks of the Dariganga Plateau, which is one of the largest volcanic fields in the Late Cenozoic volcanic province of Central and East Asia. Regular trends were observed in the composition of volcanic rocks versus time indicating cyclic changes in the chemistry of magma sources and conditions of melt generation during the formation of the Dariganga Plateau. During the early cycle, which included the middle Miocene and the late Miocene–early Pliocene stages, the metasomatically altered lithospheric mantle contributed significantly to magma formation. The magmatism of the late cycle was dominated by an asthenospheric (plume) source. Regional correlations confirmed a similar pattern of development in other volcanic areas of the province. The identified similarity indicates that the magmatic activity within the province was controlled by a single regulator; according to geophysical data, it was the Hangai plume. The sporadic occurrence of volcanism in various areas of the province reflects the pulsed activity of the mantle plume, and the absence of a strict correlation between the timing of eruptions and the scale of their productivity indicates a certain inertia in the propagation of the mantle signal from the source of activity to the periphery.