Upper Triassic Sequences of the Crimean Mountains: First Results of U–Pb Dating of Detrital Zircons

Abstract

The first results of U–Pb dating of detrital zircons from two samples that characterize the Tauric and Eski-Orda Series of the Cimmerian structural complex of the Crimean Mountains are presented. The strong similarity between the detrital zircons ages from the Lower Tauric Formation of the Tauric Series and the Salgir sequence of the Eski-Orda Series confirms the facial character of the primary relationships of these series. The studied Upper Triassic sandstones had a common source area and were most likely formed in different parts of the same sedimentary basin. It is most likely that this sedimentary basin was part of the continental margin of Baltica. The presence of a significant number of very ancient detrital zircons (>3.0 Ga, including three oldest detrital zircons grains with ages of ~3.9 Ga) in samples suggests that the crystalline complexes represented in the present-day structure of the Ukrainian Shield had very likely been primary sources of these zircons. Crystalline complexes with such ancient ages are extremely rare over the world, but are widely represented in the Podolian and Azov blocks of the Ukrainian Shield.