Sub-Cambrian peneplain

The sub-Cambrian peneplain is a geomorphic unit covering large swathes of Fennoscandia. It consists in a series of discontiguous low relief zones that are at some locations covered by sedimentary rock dating to the Cambrian. Close to the cover rocks the exposed parts of the peneplain are extraordinarily flat.

The Sub-Cambrian peneplain extends as an almost continuous belt along the eastern coast of Sweden for some 700 km from north to south. Near Stockholm and Hudiksvall the peneplain is densely dissected by joint valleys and at the High Coast is the Sub-Cambrian penepain is both highly uplifted and eroded. More inland the peneplain to the crestal region of the South Swedish Dome (South Swedish highlands) where it is dissected by joint valleys, a similar situation occurs in central Norrland, including Stöttingfjället, where the peneplain is estimated to have been uplifted about 650 meters giving origin to a series of water gaps including those of Ångermanälven, Indalsälven and Ljusnan.

To the east the Sub-Cambrian peneplain continues as an unconformity beneath the East European Platform. The island Blå Jungfrun in the Baltic Sea is an ancient inselberg belonging to the Sub-Cambrian peneplain. Being a inselberg formed in Precambrian time it was buried in sandstone after its formation and remained buried until erosion of the East European Platform freed it in geologically recent times.

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