Structural Signes of Brittle-Ductile Transitions during Exhumation of Basement Rocks of the Southwestern Foreland of the Paleoproterozoic Lapland‒Cola Collision Orogen (Belomorian Province, Lyagkomina Dam Site): Analogue Model of Deformation Stages

The Late Paleoproterozoic structural evolution of Archean polymetamorphic rock complexes at the Lyagkomina Dam site, located in the central Belomorian Province region, has been studied. Four stages of deformation were identified using geological-structural mapping and geometric analysis methods. Under conditions of regressive metamorphism from granulite to amphibolite facies, at each stage of deformation, the properties of rocks change from ductile to predominantly brittle. It is shown that the Paleoproterozoic structural evolution is associated with the exhumation of a fragment of continental crust of the central Belomorian Province region during the formation of the Lapland–Kola collision orogen.