Structural–Kinematic Parageneses and Dynamic Evolution Model of the Baltic–Mezen Shear Zone in the Phanerozoic, the Northwestern Part of the East European Platform

AbstractThe tectonic features of the Baltic–Mezen shear zone that developed along the border of the Fennoscandian Shield and the Russian Plate in the north of the East European Platform are considered. It is established that tectonic evolution of the considered zone was associated with strike-slip displacements in the basement rocks, which occurred and were dispersed in cover deposits in the form of low-amplitude faults and diagonal fold-and-thrust systems associated with sublayer detachments. The dynamic relationship of the geological–structural and geomorphic anomalies of the Baltic–Mezen zone with segments of bending of its mainline and virgation, as well as with the nodes of intersection of the main shear zone with transverse faults, is noted. Based on a study of structural and kinematic parageneses, it has been established that the Baltic–Mezen shear zone in the Phanerozoic developed mainly under dextral strike-slip displacement and transpression conditions during eight activation phases of the Caledonian, Hercynian, and recent deformation stages. Periodically there was a change in deformation regimes and kinematic inversions, and a shear zone evolved in conditions of transtension and sinistral strike-slip displacements. The kinematics of the Baltic–Mezen shear zone is consistent with the general dynamic patterns of the evolution of the East European Platform, in particular, with the formation of collision structures of the Scandinavian Caledonides, with extensive Late Devonian tectonic–magmatic events and features of the recent development of the Euro–Arctic region.