Structural architecture of the western Greater Caucasus pro-wedge: A case study from the Rioni foreland fold-and-thrust belt

Abstract

The Rioni foreland fold-and-thrust belt which is part of the western Greater Caucasus pro-wedge is located between the Lesser Caucasus and the Greater Caucasus orogens and is one of the most important examples of the collision-driven far-field deformation of the Arabia-Eurasia convergence zone (Alania et al., 2022). The Rioni foreland fold-and-thrust belt sedimentary infill consists of pre-and syn-orogenic sequences. Moreover, recent GPS and earthquake data indicate that the Rioni foreland fold-and-thrust belt is still tectonically active and the earthquakes’ focal mechanisms are mainly thrust faults (e.g., Tibaldi et al., 2017; Tsereteli et al., 2016).Fault-related folding and wedge thrust folding theories were used to interpret 2D depth-migrated seismic reflection profiles and to construct the regional balanced and restored cross-sections across Rioni foreland fold-and-thrust belt. The balanced cross-section is approximately parallel to the trust transport direction and has a total length of 64 km. On the other hand, the amount of shortening obtained for this part of the regional balanced cross-section is 40% (-42.78km).The main style of the deformation within the thin-skinned Rioni foreland fold-and-thrust belt is represented by a set of growth fault-propagation folds, duplexes, triangle zone, and a series of thrust-top basins. The evolution of the trust-top basins was mainly controlled by the kinematics of thrust sequences and competing growth fault-propagation folds and building compressional structures of the Rioni foreland fold-and-thrust belt was governed by the Greater Caucasus basement crustal-scale duplexes propagation along detachment horizons within the cover-generating thin-skinned structures.Acknowledgment: This work was supported by Shota Rustaveli National Science Foundation (SRNSF) [Structural model of the Rioni foreland fold-and-thrust belt and the Southern Slope of the Greater Caucasus (The Tekhuri river gorge area) Grant #: PHDF-21-087]