Carpathian Flysch Belt

Geologically it is a thin-skinned thrust belt or accretionary wedge, formed by rootless 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 southern boundary of the Flysch Belt in the area of the Romanian Carpathians is covered by nappes of the crystalline-Mesozoic zone.

The present rocks are not in their former position because they were detached from their basement during the closure and subduction of basins and pushed as nappe pile, forming the Carpathian accretionary wedge.

Approximately at the line of the Hodonín – Námestovo – Nowy Sacz – Neresnica distinct zone of negative gravimetric anomaly that follows the southern edge of the Bohemian Massif and East-European Platform, which are underthrust below the Carpathians.

From the neotectonic point of view, the whole area of the Flysch belt is affected by extension, locally up to 12 mm per year.

Outer Carpathian tectonic units included in the Flysch Belt are divided according to their structural position in the frame of mountain range.

Generally these principal zones can be recognized:[4][5] Sedimentation in the basins of the Flysch Belt is recorded since the Upper Jurassic period up to Oligocene resp.

In the past it was believed that the source area of the clastic sediments supplied to the basins was built by a system of linear island elevations which were parallel to the axis of the mountain chain.

Loading of the Flysch zone nappes forced subsidence in its foreland, causing formation of the Carpathian foredeep.