Neotectonic Evolution of the Caucasus: Recent Vertical Movements and Mechanism of Crustal Deformation

Abstract—It is generally recognized that the formation of the fold-and-thrust tectonic structures of mobile belts on continents is associated with crushing and narrowing of the Earth’s crust due to collision of lithospheric plates. The deformation of the Caucasian lithosphere in the recent time is generally consistent with these ideas. However, the block differentiation of the Caucasian lithosphere brings specificity into the directionality of recent vertical and horizontal movements. In this paper, we analyze vertical movements of the Caucasus estimated by means of high-precision leveling over a period of more than a century and consider their spatial correlation with the tectonics, seismicity, stress-strain state, and geophysical fields. A clear correlation indicating the deep tectonic nature of the long-term uplifts of the Caucasus crust is revealed. The differentiation of the Arabian plate movement causes partitioning of the Caucasus territory into provinces that differ by the pattern of recent movements, orientation of faults, and stress-strain state of the geomaterial. These provinces also have distinctions in seismicity in terms of the number of seismic events and focal mechanisms of the earthquakes. We propose a model of a deformation mechanism of the Greater Caucasus, which accommodates the long-term trend of the Caucasus uplift in the conditions of general shortening of the Earth’s crust. The results of the analysis provide a basis for discussion of a probable mechanism of neotectonic evolution of the Greater Caucasus, which can be used in the seismic hazard assessment of the North Caucasus.