Insight into Oligocene–Early Miocene palaeogeography of the Carpathians in Poland: first cycle and recycled detrital zircon provenance in the Menilite and Krosno formations

Abstract

A set of 6368 U–Pb isotope ages of detrital zircons from 53 samples of the Oligocene to Early Miocene Menilite and Krosno formations (Outer Western Carpathians) was obtained and interpreted in terms of their sources. In both units the most frequent are mid-Variscan and Cadomian zircons that were derived from the Variscan Internides underlying the studied basin, and from the Brunovistulia Terrane, respectively. The coincidence of detrital zircon ages and clast ages indicates that zircons of that age can be at least partly of first cycle. Sveconorwegian and Calymmian–Statherian recycled zircons of Baltica origin, highly frequent in the Menilite Formation, are most probably sourced from Lower Devonian sediments of the Małopolska Massif. The Oligocene basin of the Menilite Formation was supplied in detrital material largely from the north where the Meta-Carpathian Swell was elevated in the area of the Małopolska Massif and Brunovistulia Terrane. During sedimentation of the Krosno Formation this source expired. A considerable input to the Menilite Formation of Baltica derived zircons and a limited number of zircons from sources located SE of the study area suggests that they were deposited in a relatively shallow and isolated basin. Supplementary material : A list of samples collected, lithological features of sampled rocks and lithostratigraphic sub-units, methods of zircon separation and U–Pb dating, and detailed results of the dating of detrital zircons, with concordia plots and probability density diagrams are available at https://doi.org/10.6084/m9.figshare.c.7100071