A LOCALIZED STUDY OF GEORGIAN CAUCASUS' TECTONICS

Deformational structures within the Kura River Basin, located northwest of the Georgian capital of Tbilisi, are thought to be a microcosm of the regional structural style of the Caucasus region. Details of the region’s structural evolution are indistinct; thorough mapping of the area is necessary in understanding the structures in the area and will expectantly provide insight into the paleo- and neotectonics of the surrounding region. Multi-disciplinary data (e.g. regional seismicity, GPS) is being integrated to determine if small-scale structures agree with contemporary tectonic theory and if these structures (and their components) improve understanding of some proposed models for deformation in the area. The study area covers approximately 85km² of the north and south sides of the Kura River Basin northwest and south/southeast of the city of Kaspi. Using traditional and modern methods, field mapping at a 1:25,000 scale was completed in this area to better understand the Late Paleogene and Early to Middle Neogene stratigraphic relationships and deduce the evolution of present day structures. The juxtaposition of these units generally agrees with GPS-derived stress axes and compression directions; however, on a local scale, the position of these units suggests a more complicated tectonic history. Within the study area, a mapped thrust fault trends NW-SE (~300°), approximately normal to the modern principal compressive stress direction (σ₁=030°), while strike-slip features appear to run parallel to this direction insinuating a different σ₁. The first phase of the project, geological fieldwork, was completed during the summer of 2004 and preliminary geological mapping results agree with previously calculated convergence axes in the Kura River Basin. Successive research phases will approach the following areas: subsurface interpretation, an assessment of the quality of available geodetic and geophysical data and its relevancy to the project, the application of relevant geodetic and geophysical constraints to study area (if necessary), and proposal of local tectonic evolution, its regional implications, and comparison to other models.