Structure and Evolution of the Belomorian–Severodvinsk Shear Zone in the Late Proterozoic and Phanerozoic,East European Platform

Geotectonics - The tectonics, morphological features, and development stages of the Belomorian‒Severodvinsk shear zone (northwestern part) found in the East European Platform are considered....     

Structural assemblies of the Vladimir-Vyatka dislocation zone and the position of the Puchezh-Katunki Crater,East European Platform

The Puchezh-Katunki (PK) structural unit is situated in the Middle Volga region of the central East European Platform (EEP). It is expressed as a system of complex dislocations and a meteoritic crater with a central uplift. Based on the results of structural study, the attributes of its long evolution have been revealed. Four deformation stages have been established: Hercynian (1) fold-nappe and (2) trancpressional deformations, (3) formation of the Early Jurassic impact crater and the related system of radial-concentric faults, and (4) low-amplitude tectonic reactivation of Hercynian faults during the Kimmerian-Alpine stage of evolution. In general, the PK structural unit is localized in the most strained segment of the Vladimir-Vyatka Dislocation Zone, which separates the largest structural domains of the EEP. This is a long-lived zone, which developed cyclically beginning from Paleoproterozoic collisional events and up to the Kimmerian-Alpine stage of reactivation. Such a direct impact to the cluster of concentrated deformations in one of the largest tectonic zones of the EEP seems unlikely. Nevertheless, available evidence, including the estimated stress related to the impact effect (up to 50 GPa) and its decrease with depth, does not rule out the meteoritic origin of the PK structural unit.     

Trace elements in Upper Devonian rocks of the Andoma Hill zone of fold-and-fault dislocations (southeastern Onega region) as indicators of source areas

The paper reports the results of lithogeochemical studies of the Upper Devonian rocks from the Andoma Hill zone of fold-and-fault dislocations (SE Onega region). The rocks are characterized by the negative Eu anomaly (from 0.4 to 0.65) that maks them different from modern sediments of the White Sea. The latter can be regarded as the average composition of mainly Archean (Karelian–Kola) part of the Baltic Shield. In terms of the contents of some trace elements, they also differ from the Vendian rocks of the Zimnii Bereg area. Since the considered rocks are geochemically similar to the Svecofennian metamorphic rocks and Paleoproterozoic granite rapakivi, they could be formed by the erosion of these complexes. The clastic material was transported via a channel confined to the Baltic Shield and Russian Platform junction known as the Polkanov geoflexure.     

Deep Electrical Conductivity in the Vicinity of the Orsha Depression: 2D REBOCC Inversion of Synthetic and Observed Magnetotelluric Data

Izvestiya, Physics of the Solid Earth - Abstract—The geoelectric structure of the junction region between three largest segments of the East European Craton (EEC)–Volga–Uralia,...