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

Abstract

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.