Tectonics in the Baltic Shield in the period 2000-1500 million years ago

Abstract

The effects of deformation during the SvecokareIian orogenic episode on pre-2000 m.y, sedimentary and volcanic assemblages, developed in contrasted crustal environments, are compared end related to the effects of coeval deformation on older crystalline basement. Comparability in both the polyphase structural sequences and the orientations of successively formed structural elements in schistose and gneissose cover rooks indicate an overall unity of the complex framework from eastern Finland to Sweden. Correspondence of this framework with that resulting from deformation of 2200-2000 m.y, cover rocks during the Laxfordian orogenic episode in northwesten Britain, together witch comparison with the effects of coeval deformation of crystalline basement, suggest a unity of structural framework from Finland to Scotland c 2000–1700 m.y. ago.
Epeirogenic movements in the post-orogenic cratonic stage of the orogenic cycle c 1700–1500 m.y. ago, or even younger, were associated with granite emplacement, sedimentation, extrusive volcanism and faulting. The fault patterns developed on the lower crust had a marked effect on the geological evolution of the region during the remainder of Proterozoic and Phanerozoic times.