Sources of Neogene Rare Metal–Titanium Placers of the Northeastern Wall of the Dnieper–Donets Basin: First Results of U–Pb Geochronological Studies of Detrital Zircon

Abstract

Runoff of terrigenous material involved in the structure of Neogene rare metal–Ti placers of the northeastern side of the Dniepr–Donets Basin (DDB) is determined using lithological and mineralogical methods including U–Pb geochronological and chemical study of detrital zircon. The peculiarities of an assemblage of accessory minerals of heavy fraction of placers, the morphology of individual grains, and the depletion of most zircons in U, Th, Y, and Yb indicate that the material was sourced from chemical weathering mantles, which probably developed after Proterozoic (70%) and Neoarchean (15%) metamorphic rocks. The presence of Paleozoic zircon crystals and a higher U, Th, Y, and Yb content are evidence of the erosion of igneous rocks of the Neoproterozoic–Early Paleozoic trap complexes and Devonian intrusive and volcanosedimentary rocks of the DDB. The involvement of clasts of the above rocks in sedimentary recycling was promoted by the evolution of abundant DDB salt tectonics.