reconstruction of the older phases of development is not possible because of absence of pre-triassic rocks. the development of pieniny klippen belt started on passive margin of european platform in lower jurassic with rifting and tectonic subsidence of oravic unit. during the middle jurassic to lowermost cretaceous an elevated continental ribbon called the czorsztyn ridge evolved due to the thermal uplift and continental break-up at the southern side of the czorsztyn ridge. rifting resulted in the opening of basinal area called the kysuca basin or vahic ocean (south penninic or piemont ocean equivalent) to the south of the oravic area. in the upper jurassic entire oravic domain began to thermally subside. since lowermost cretaceous time probably an asymmetrical rifting affected the area to the north of the czorsztyn ridge where a magura basin (north penninic or valais ocean equivalent) started to evolve.