BASIN MODELLING Tectonic development of the Ararat Basin, Lesser Caucasus, Armenia

The Paleocene-Miocene Ararat basin is located in the foreland to the south of the NW-SE trending Lesser Caucasus orogenic belt in the Republic of Armenia.In the foreland to the north are the hydrocarbon-bearing Kura andRioni basins of Georgia. On the basis of recent studies in Armenia together with a critical review of previous work, we propose a new model for the structure and development of the Ararat basin. The basin's development is here interpreted within a compressional regional framework which has been dominated since the Late Cretaceous by the closure of Neotethys and the Arabia-Eurasia collision. Previous studies have considered that the Ararat basin is an extensional graben, and that surface exposures of Palaeozoicrocks are related to horst structures controlled by normal faults. However new data suggest that surface structures in a study area in the northern flank of the basin arein fact oblique-slip reverse and thrust faults, activated in post-Oligocene-Miocene times (Fig.1). Regional compression resulted in the formation of asymmetric, fault-controlled folds including the Lanjanist and Urts anticlines to the NW of the Ararat basin and Parakar-bared and Sardarapat structures to the north and NW. The structural pattern is complicated by secondary normal faults which have resulted in gravitational slope processes and erosion. Pliocene and Quaternary (active) structures show evidence of structural inheritance. In the subsurface, the Ararat basinis interpreted to contain obduction-related ophiolitic nappes which are exposed at the surface at various locations such as Sari Pap. Together with compressional anticlines and thrust faults, these Mesozoic nappes have potential as structural traps for hydrocarbons.