Junction zone structure of the Sarmatia, Volga-Uralia, and Fennoscandia microcontinents as part of the East European Platform basement

Research subject. The structure of the pre-Paleozoic deposits and different-age Precambrian basement of the East European platform based on geological and geophysical data.Aim. To trace the evolution of the area under study and to study the geodynamics of processes in order to reconstruct the paleostructure of the Baltica continent.Materials and methods. The current state of the consolidated crust was studied using a geological interpretation of seismic profiling data (transects: “EB-1”, “Tatseys”, “Magnit”) and materials of gravity and geomagnetic surveys. The material composition of the basement rock complexes was studied based on drilling data.Results. The Baltica continent forms the basement of the modern East European Platform. After the Sveconorwegian folding about 1000 Ma, Baltica had become part of the Rodinia supercontinent and merged with the North American platform. A passive continental margin with the Riphean-Vendian sedimentary cover was formed on the eastern Baltica edge. The Petrozavodsk-Khopersky orogen, which arose in the place of the Karelian (Early Proterozoic) Petrozavodsk-Khopersky paleoocean, was reconstructed. The submeridional suture was a result of this paleoocean closure. The orogen structure, as well as that of the paleocontinent Baltica, was disturbed and partially destroyed by subsequent tectonic processes, which continue at the present time with modern rifting.Conclusions. The closure of the Petrozavodsko-Khopersky paleoocean led to the formation of the Baltica continent, which included three microcontinents – Sarmatia, Fennoscandia and Volga- Uralia. Baltica became part of the Rodinia supercontinent during the Sveconorwegian orogeny. Volga-Uralia was located on the border with the PaleoPacific and had a Late Riphean sedimentary cover of the Rodinia supercontinent. This margin underwent destruction during a collision with the Timanides. The scale and extent of the reconstructed Petrozavodsk-Khopersky orogen is comparable to Paleozoic orogenic belts, such as Cadomides, Caledonides, Variscides, or Timanides.