Recent mountain-building at the boundary juction of the North-Western Caucasus and intermediate Kerch-Taman Region, Russia

Abstract

In this paper the recent evolution of marginal segment of the North-Western Caucasus orogen in its junction to Kerch-Taman periclinal trough was studied. Geomorphological analysis included geological, tectonophysics data and digital elevation models was carried out. The North-Western Caucasus torn-folded morphostructures that had their extension in intermediate Kerch-Taman region westward to North-Western Caucasus mountain structure are both established to be developed in uniform regional compression settings. The prevailing horizontal compression direction changed from N–E in the North-Western Caucasus to the meridional one in Taman region, which was expressed in the reorientation of the axes of the folded morphostructures and geophysical anomalies from N–W to the latitudinal direction. The separation of the compressional vectors occurred in Pliocene-Quaternary period. Pre-Pliocene fault structures of N–E strike in this area were replaced with meridional Anapa-Dzhiginka and Abrau active fault zones.We compared Abrau zone with Anapa-Dzhiginka zone and established the faulting in Abrau zone became more dynamic in Pliocene-Quaternary stage, we revealed clear signs of vertical amplitude droppable-sliding kinematics of 500–600 m of normal fault deformation in Abrau zone during this stage. Abrau zone is the Greater Caucasus western boundary zone.The possible reasons for the restructuring of regional structural geometry and lateral transition activity of the faults transverse to the Northern-Western Caucasus orogen, are considered.