First U–Pb LA-ICPMS Zircon Ages from the Devonian–Carboniferous Boundary Ash Beds in Domanik Facies of the Kama–Kinel Trough System (Volga–Ural Petroleum Province, East European Platform)

For the first time, zircons from thin volcanic ash layers interbedded within organic-rich Domanik facies (hydrocarbon source rocks) at the Devonian–Carboniferous boundary have been dated using the U–Pb LA-ICPMS method. The studied material derives from core samples of two boreholes located in the axial and marginal zones of the Kama–Kinel Trough System within the Volga–Ural Petroleum Province. In the axial zone, the base of the Siphonodella quadruplicata conodont zone yielded a concordant U–Pb age of 358.3 ± 1.7 Ma. In the marginal zone, the upper part of the Palmatolepis gracilis expansa Zone provided a concordant U–Pb age of 360.0 ± 1.2 Ma. These ages agree, within analytical uncertainty, with the current conodont-based chronostratigraphic framework and allow refinement of the onset of the Hangenberg Event in the studied basin.