Lithofacies characteristics of the Vorobiev deposits in the Voronezh anteclise

Abstract

Introduction: Lower Givetian deposits of the Vorobiev formation were first described by A. I. Lyashenko in 1953 by the core of well No. 86 near the village of Vorobievka in the Voronezh Region. Despite the conducted studies, the facial aspects of the formation of the studied formations, with the exception of their distribution in the south-east of the anteclise, have not been thoroughly studied yet. 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: A detailed lithological characteristic of the main types of Vorobiev formations of the Voronezh anteclise were used to show that their formation within almost the entire studied area occurred in coastal-marine conditions with weak and medium activity of the hydrodynamic regime and in shallow-marine conditions with weak activity of the hydrodynamic regime. What is more, coastal-marine conditions prevailed within most of the area of the Voronezh anteclise. At the boundaries of the areas lacking in deposits in the central and south-eastern parts of the studied area, Vorobiev deposits accumulated in the transitional conditions with clay sedimentation. Conclusion: The Vorobiev period is characterised by the development of sand-clay formations of coastalmarine facies in the south, south-east, and north-west of the studied area, which to the north and north-east are replaced by shallow-marine clay sediments.