Exploration and recognition of active basement thrust sheet and crustal-scale duplex in the central Lesser Caucasus orogen using seismic reflection profile, Georgia

Abstract

The Lesser Caucasus (LC) double-wedge orogen accommodates the crustal shortening due to far-field effects of the collision between the Arabian and Eurasian plates. Subsequent convergence of Arabia and Eurasian plates during the late Alpine time caused extensive intracontinental deformation in the LC. Herein we introduce the active deformation structural style of the Georgian part of the LC orogen based on seismic reflection profile, several oil-well, and surface geology data. Seismic reflection data reveals the presence of a Khrami basement thrust sheet, fault-related folds, triangle zone, and duplexes. The rocks involved in the deformation range from Paleozoic basement rocks to Pliocene-Quaternary basaltic lava flows.Pliocene-Quaternary lava flows are involved in compressional deformation and are related to an out-of-thrust sequence of the Khrami basement thrust sheet. Based on the interpreted seismic reflection profile, the crustal-scale duplex was recognized under the basement thrust sheet which propagates northward along the Early Jurassic shale layers.The structural architecture and tectonic evolution will be briefly presented and discussed in the new regional balanced and reconstructed cross-section across the axial zone and retro-wedge of the LC and published fission-track data (Gusmeo et al., 2021, 2022), as well as detailed examples of active tectonics, and seismicity (e.g., Tsereteli et al., 2016).ReferenceGusmeo, T., et al. (2022). Tectono-thermal evolution of central Transcaucasia: Thermal modelling, seismic interpretation, and low-temperature thermochronology of the eastern Adjara-Trialeti and western Kura sedimentary basins (Georgia). J. As. Earth Sci. 238, 105355.Gusmeo, T., et al. (2021). Structural inversion of back-arc basins-The Neogene Adjara-Trialeti fold-and-thrust belt (SW Georgia) as a far-field effect of the Arabia-Eurasia collision. Tectonophysics 803, 228702.Tsereteli, N. et al. (2016). Active tectonics of central-western Caucasus, Georgia. Tectonophysics 691, 328-344.