Carpathian Flysch Belt

The Carpathian Flysch Belt is an arcuate tectonic zone included in the megastructural elevation of the Carpathians on the external periphery of the mountain chain. Geomorphologically it is a portion of Outer Carpathians. Geologically it is a thin-skinned thrust belt, formed by rootles nappes consisting of so-called flysch - alternating marine deposits of claystones, shales and sandstones which were detached from their substratum and moved tens of kilometers to the north (generally). The Flysch Belt is together with Neogene volcanic complexes only tectonic zone occurring along the whole Carpathian arc.

The Carpathian Flysch Belt is connected to the flysch belt of the Alps (Rhenodanubian Flysch) and continues through the territory of the Czech Republic, Slovakia, Poland, Ukraine and Romania. The belt is about 1,300 km long and 60 – 75 km wide. Sequences of the Flysch belt are thrusted over the margin of Carpathian foredeep in the north. The foreland of the Flysch belt is built by Bohemian Massif in the west, East-European Platform in the north and Moesian Platform in the east. In the south it is bounded by the Pieniny Klippen Belt in its western segment. The southern boundary of the Flysch Belt in the area of the Romanian Carpathians is covered by nappes of the crystalline-Mesozoic zone.

The Zone is composed basically of sedimentary rocks which were deposited since the Upper Jurassic up to Cretaceous-Paleogene time. The Flysch Belt is structural remnant of several basins, developed in front of the advancing ancestral Carpathians and later incorporated in the Tertiary Carpathian fold and thrust belt. Former sedimentary basin of the Carpathian Flysch belt were portion of the Alpine Tethys Ocean. Present rocks are not in their former position because they were detached from their basement during closure and subduction of basins and pushed as nappe pile, forming Carpathian accretionary wedge. Fold axial planes have generally north vergence, North-western in the western sector, northern in the central sector and north-eastern to eastern in the eastern sector. Only nappes of South Carpathians have eastern to south-eastern vergence.

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