RELATIONSHIPS OF LATE PALEOZOIC VOLCANIC RIFT BELTS AND GRANITIC BATHOLITHS ON THE EASTERN SLOPE OF THE URALS TO PLUME TECTONICS

Abstract

In an increasing number of recent publications, one can find the statement that it is impossible to explain the formation of foldbelts, especially at late stages of their evolution, in terms of plate tectonics. The Ural Foldbelt is not an exception in this respect. The suggested suprasubduction development of the Late Paleozoic Magnitogorsk, Irgiz, and Valer’yanovka volcanic belts on the eastern slope of the Urals and their analogy with active island arcs comes into conflict with the succession of their evolution and composition of rocks. As is known, the evolution of suprasubduction island-arc volcanic belts is characterized by progressive increase in their alkalinity (potassium content) from the ocean toward the continent, i.e., from forearc to backarc zones. Such zoning is not revealed in the Late Paleozoic rift-related volcanic belts of the eastern slope of the Urals either from west to east (from the Magnitogorsk belt to the Irgiz belt and farther to the Valer’yanovka belt) or in the opposite direction.