Geochemistry of Bashibos-Bajrambos metasedimentary unit, Serbo-Macedonian massif, North Macedonia: Implications for age, provenance and tectonic setting

Abstract

Metasediments of the Paleozoic Bashibos-Bajrambos unit, comprising the western perimeter of the Serbo-Macedonian Massif in SE Republic of North Macedonia, were investigated by employing whole-rock geochemistry and detrital zircon geochronology to put constraints of age, provenance and depositional tectonic setting. The metasedimentary unit consists of polymetamorphic and highly altered pelitic mica-schists and phyllites and metamafic rocks. The first limited data from the whole-rock composition of the metapelites and zircon Th/U ratios suggest derivation of detrital material from felsic and recycled older upper crustal sources. At the same time, mafic samples indicate an origin from a volcanic source without a significant contribution from ultramafic rocks. Whole-rock data and the detrital zircon record suggest that deposition of the sequence took place in collision-related, foreland basin, formed by the merging of Pelagonian and the Serbo-Macedonian Massifs. The population of the youngest recorded zircons indicates Early Permian sedimentation. The detrital zircon record speaks for significant sedimentary input of old crustal material from the Serbo-Macednonian Massif, while younger Carboniferous-Permian magmatic zircon populations support the significant influence of the Pelagonian Massif.