Pre-Mesozoic Crimea as a continuation of the Dobrogea platform: insights from detrital zircons in Upper Jurassic conglomerates, Mountainous Crimea

Abstract

U–Pb dating, Hf-isotope, and trace-element studies on two detrital zircon samples from sandstone interlayers in the Upper Jurassic conglomerates of the Southern coast of the Mountainous Crimea provide new information on the primary crystalline complexes from which those conglomerates were sourced. The U–Pb age spectra of studied zircons suggest that they were most likely sourced from the (meta)sedimentary complexes of the Eastern and Western Pontides blocks and the Dobrogea platform. In particular, a close similarity of the Precambrian age spectra with the detrital zircons from Late Neoproterozoic–Late Paleozoic (meta)sedimentary complexes of the Dobrogea block provides strong supporting evidence for the affinity between the Pre-Mesozoic basement of the Crimea and the Dobrogea platform. The zircons in the first sample were recycled through Dobrogea sedimentary complexes and originated from terranes with Amazonia affinities, while zircons in the second sample were recycled through the Taurides and originated from terranes related to northeastern Africa and Arabia. The strong similarity of the Precambrian parts of the age spectra of the Dobrogea complexes and the sample K15-007 suggests a resemblance of the Crimea’s Pre-Mesozoic foundation and the Dobrogea platform. Initial analytical data are provided in Electronic Supplementary Materials A (ESM A). Descriptions of measurement parameters, methodologies, and constants used to process primary analytical data and some processing results are reported in ESM B (Figs. B1–B8). Schemes of locations within Balkans–Anatolia–Black Sea–Caucasus region the crystalline complexes with Jurassic, Triassic, Permian–Carboniferous, as well as Late Neoproterozoic–Cambrian and Ordovician–Devonian ages are in ESM C (Figs. C1, C3–C5).