The Pieniny Klippen Belt is in geology a tectonically and orographically remarkable zone in the Western Carpathians, with a very complex geological structure. It is a narrow (only 0.4 to 19 km) and extremely long (about 600 km) north banded zone of extreme shortening and sub-vertical strike-slip fault zone, with complex geological history, where only fragments of individual strata and facies are preserved. The Pieniny Klippen Belt is considered one of the main tectonic sutures of the Carpathians and forms the boundary between the Outer (externides a thin-skin thrustbelt) and Central Western Carpathians (internal thick-skin thrustbelt).
The Pieniny Klippen Belt emerges from beneath the Neogene sediments of the Vienna basin near Podbranč in western Slovakia and continues eastward to Poland, where it bends and returns to Slovakia in the area of Pieniny. The klippen belt then continues to Ukraine and ends in Romania. In some places it is covered with younger deposits, for example in the Podhale basin in Poland, or in the Vihorlat Mountains in Slovakia.
Klippes, which are the most characteristic features of the belt, are Jurassic to lower Cretaceous lenses - rigid blocks of limestone, tectonically separated from their unknown substratum. These blocks are also cropping out in tectonic windows in the overlying middle Cretaceous to Paleogene sediments. Strong tectonic deformation is a result of two main phases during the Alpine orogeny. The oldest phase is called the Laramide phase or Jarmuta phase and occurred in the Cretaceous and Paleogene periods. It caused thrusting of the nappes. The second phase is called the Savian or Helvetian phase. It was induced by subduction of the Northern Penninic ocean and caused the formation of the Carpathian Flysch Belt.