Geochemistry and age of detrital zircon from the Quaternary deposits from the Ufaley block (Middle Urals): provenance and the problem of Precambrian

Research subject. Detrital zircons from the Quaternary deposits from the frame of pyroxenite composing the Shigirsky hills in the western part of the Ufaley block. Aim. The verification of the Pre-Cambrian dating, evaluation of the substrate type and geotectonic settings of rocks enclosing ultramafites of the Ufaley block. Materials and methods. U-Pb isotope dating and determination of rare and rare-earth elements in detrital zircon by laser ablation, RSMA investigation of minerals, establishing of zircon nature and provenance and the distance of zircon migration. Results. Dominant Paleoproterozoic (2100–2000 Ma) maximum for the distribution of detrital zircon age accompanied by lower picks of the Archean and Neoproterozoic-Lower Ordovician age has been established. Detrital zircon was derived from continental-type sources corresponding to igneous and metamorphic rocks of basic, intermediate and acidic composition. The transfer distance was negligible. Conclusions . Zircon morphology, its internal structure, mineral inclusions, geochemistry and age allow to suggests the similar protolith and joint the Precambrian evolution at least the western part of the Ufaley block and Taratash and Alexandrovsky blocks, which are the fragments of crystalline complexes of the Archean Volga-Uraliya craton. This conclusion supports additionally by similarity in composition of high-Ca mafic-ultramafic rocks known in these blocks.