Lithofacies characteristics of the Petino deposits in the Voronezh anteclise

Abstract

Introduction: Sedimentary rocks of the Upper Frasnian Petino suite were first described by V. N. Krestovnikov in 1925. Since then, they have been studied by a number of authors. However, the formations within the whole Voronezh anteclise remain understudied. The aim of this article is to fill this gap. Methodology: The deposits were studied using lithofacies analysis. The facie maps were based on the sections of several hundred wells. Results and discussion: The results of a detailed lithological characterisation of the main types of Petino deposits in the Voronezh anteclise demonstrated that the formation of the studied sediments practically all over the studied territory occurred under shallow-marine conditions with the weak and medium activity of the hydrodynamic regime. At the borders of the areas lacking deposits in the central and south-eastern parts of the studied area, Petino deposits accumulated in the coastal-marine conditions with different hydrodynamics of the environment, from weak to high, with a sand-clay sedimentation. Conclusions: The Petino period is characterised by the development of sand-clay formations of coastal-marine facies in the south and south-east of the studied area, which to the north and north-east are replaced by coastal-marine carbonate-argillaceous sediments.