Nowe stanowisko osadów miocenu koło Dubiecka

Marek Cieszkowski, Krzysztof Witek, Antoni Wójcik



A patch of Miocene deposits was recently discovered at Przedmieście Dubieckie on the left bank in San river valley 2.5 km WNW of Dubiecko (36 km W of Przemyśl). The Miocene is represented here by sands with sandstone and fine gravel intercalations discardantly overlying folded Flysch deposits of the Skole nappe. A rich micro- and macrofaunal assemblage found in the upper part of the profile indicates, similarly as the nature of the deposit yielding it, a sedimentation in shallow marine basin. The paper presents ,the lithological characteristics of the Miocene deposits and their foraminifer assemblage. The assemblage comprises single specimens of Uvigerina costata, Marginulina hirsuta, Cibicides conspiciendus, Orbulina suturalis, Globigerina bulloides, Globigerinoides trilobus which are characteristic of the assemblage II A (Lancentdorfian fauna) known from basal parts of the Badenian from the Carpathian Foredeep. Shallow-water species such as Elphidium crispum, E. fichtelianum, Ammonia beccari, Asterigerina planorbis and Heterostegina costata quantitatively predominate in the microfaunal assemblage from sands so this assemblage from Przedmieście Dubieckie may be regarded as shallow-water biofacies of the assemblage II A. Taking into account the extent of transgression of the Miocene sea in marginal parts of the External Carpathians and the presence of traces of marine abrasion in basal parts of Miocene deposits from other localities in the vicinities of Dubiecko there is appears a question whether or not at least a part of so-called forland destruction horizon from Polish Carpathians did originate in result of abrasion by Miocene sea entering the area of the Carpathians.

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