STRUCTURAL ARCHITECTURE & TECTONIC DEVELOPMENT OF THE LATE CENOZOIC KURA BASIN OF THE CAUCASUS MOUNTAINS (AZERBAIJAN) IN A BROAD CONTINENTAL COLLISION ZONE

The Late Cenozoic Kura basin in Azerbaijan represents an intermontane basin between the Greater and Lesser Caucasus Mountains, ~600 km north of the Arabia–Eurasia collision zone. The nearly ~125-km-wide Kura Basin contains 5- to 7-km-thick, Plio–Pleistocene fluvial, lacustrine, and alluvial fan deposits, forming a geological archive of sedimentary, climatic, and tectonic processes that have occurred in an oblique collision zone. As a SW–vergent tectonic wedge, the Kura Basin is bounded in the west by an active frontal thrust zone facing the Lesser Caucasus, and in the east by the Greater Caucasus Mountains that have been uplifting fast during the past 5 m.y. This tectonic system produced the Kura fold–thrust belt (KFTB), which is currently experiencing average shortening rate of 8 mm/yr. This active deformation has resulted in the development of major fault systems in the Kura Basin. The SE-flowing Kura River is a major, axial fluvial system, draining the Kura Basin, and its main channel and tributaries show sharp 90° deflections corresponding to active faults. Although some of the faults in the region have been mapped in previous studies, most faults, their orientations and slip directions are little known. Yet, the Kura Basin and its environs are seismically active as evidenced by historically important, high-magnitude earthquakes. Understanding the fault patterns and kinematics have not only scientific significance but also societal relevance, both of which motivate me and my thesis work.

Working hypothesis posits that the active deformation in the KFTB is a result of strain partitioning between thrust and strike-slip fault systems as a result of the far-field stress effects of the oblique collision between Arabia and Eurasia. The combination of thrust and strike-slip faults caused both basin–parallel and basin–perpendicular segmentation of the Kura Basin, producing sub–basins and topographic highs. The possible impact of this segmentation on sedimentation patterns is also an important question. This is a case study of how young sedimentary basins in active orogens become segmented, inverted, and integrated into growing mountains in convergent zones. Its results should help us predict where in Azerbaijan we can anticipate future earthquakes, and prepare a seismic geohazard map based on the studied fault patterns and kinematics in the Kura Basin.