3D Model and Structural-Kinematic Evolution of the Pre-Jurassic Crystalline Basement of the Western Georgia

Abstract

The modern structure of Western Georgia is determined mainly by the meridional (sub-meridional) and latitudinal systems of faults covering different depths of the Earth's crust. The noted faults are often-sided boundaries of the blocks of the crystalline basement of the Earth's crust, creating a picture of its mosaic-block structure. The analysis of the lithofacies and thicknesses of the sedimentary cover developed within their limits, in several cases, indicating their autonomous and inversion nature of development. The comparison of geophysical and drilling data and applying the system analysis method of disjunctive structures made it possible to clarify some issues of the structural-kinematic evolution and morphogenetic of individual blocks and faults of the pre-Jurassic crystalline basement within the limits of the Southern Caucasus. A 3D physical model of the surface of the crystalline basement constructed by us within Western Georgia shows the spatial arrangement and the character of the inversion nature of individual blocks, indicating the manifestations of the Alpine and Late Alpine orogeneses. Analysis of the actual material, geophysical, and geological data for the intra-Caucasian intermountain area allows us to draw the following conclusions: the Georgian Block (a fragment of the Transcaucasian median massif, microplates, and terranes), with a pre-Jurassic crystalline basement exposed in its central part, is divided into the western and eastern subsidence zones, which in turn disintegrate into separate blocks. From the central zone of the uplift of the Georgian Block to the east and west, a gradual "stepwise" subsidence and tilting of the blocks of the crystalline basement is outlined. Similar structures are known in the literature as the so-called tilt blocks.