Lower Devonian of the Varandej-Adz’va structural zone (stratigraphy, korrelation)

The Varandej-Adz’va structural zone located in the northeastern part of the Timan-Northern Ural region, where Lower Devonian represented all stages: Lochkovian, Pragian and Emsian. The Lower Devonian sediments were accumulated under conditions of shallow marine basin with unstable sedimentation (argillaceous-carbonate, carbonate, sulphate-carbonate and mixed clastic-argillaceous-carbonate), shown in different types of a rhythmical composition of sections.