Plio-Quaternary paleostress regimes and relation to structural development in the Kertch–Taman peninsulas (Ukraine and Russia)

In the Kertch–Taman peninsulas, located between the Crimean and NW-Caucasus Mountains, deep troughs developed since Oligocene time. Sediments were subsequently folded. Folding was associated with thrusting. Paleostress analyses allowed constraint of the tectonic evolution of the area. An extensional event occurred before folding, perhaps related to the trough development. This event was followed by compression associated with Plio-Quaternary folding. Stress tensors determined in older rocks in the Crimean and NW-Caucasus belts are correlated with this regional Plio-Quaternary compression. In detail, N–S compression followed NW–SE compression. This change in direction could be explained by a change of the direction of convergence of the Black Sea Plate with the Scythian Plate. The NW–SE compression induced NE–SW folds in the southern part of the peninsulas. The N–S compression corresponds to E–W folds of the northern part, suggesting a northward propagation of the deformation front. The structural evolution of the Kertch–Taman region is controlled by (1) pre-existing structures, (2) a change in the direction of compression related to a change of the direction of convergence of the Black Sea with the Scythian Plate and (3) the northward propagation of the compressional front with the continuing indentation of the Black Sea block.