Composition and Sources of Middle Paleozoic Basalts of the Vilyui Paleorift

摘要

During the Phanerozoic, the Siberian Craton was repeatedly involved in intraplate activity that produced flood basalts, rift and aulacogen systems, dike swarms, kimberlite fields, and alkaline massif belts. The geology and petrology of these complexes have been well studied, whereas some fundamental genetic problems—the sources of intraplate magmatic activity, their temporal evolution, and the geodynamic mechanisms that were responsible for repeated involvement of the Siberian Craton in intraplate activity—remain unsolved. The paper considers these problems in relation to the Middle Paleozoic magmatism of the Vilyui aulacogen (paleorift) on the basis of geochemical and Sr-Nd data on magmatic rocks that developed along its northwestern flank (Fig. 1). The occurrence of kimberlite and mafic magmatism in this part of the rift system is of special interest for deciphering deep-seated sources and geodynamic conditions of this magmatism in the southeastern Siberian Craton.