MEREDITH, DAVID J., Keele University, Dept. of Earth Sciences, Newcastle-under-Lyme, Staffordshire, England

ABSTRACT: Geological and Geodynamic Evolution of the Black and Caspian Seas

The Black and Caspian Seas of eastern Europe are two of the deepest basins in the world but the mechanisms that have controlled their subsidence history remain poorly understood. A lithospheric-scale tectonic modelling application has been developed to investigate the interplay, of geological and geodynamic processes that have controlled the evolution of these deep basins. It enables the forward modelling of extensional basin evolution followed by deformation via subsequent extensional and compressional events.

Modelling, constrained by results from regional basin analysis of the Black Sea, shows that the basin cannot be attributed entirely to either extensional or compressional tectonics. The uniform lithosphere extension mechanism cannot account for the thickness of sediment fill observed in the basin while the simulation of compressional deformation around the basin edges does not produce the large magnitude of subsidence in the central basin. Model results strongly suggest an influence of deep crustal and mantle lithosphere processes in controlling the evolution of the Black Sea. Combined with basin analysis techniques, modelling is currently being applied to the southern Caspian Sea, which has a similar tectonic history to the Black Sea basin, but is much deeper with over 20 km of subsidence.

It is hoped that the detailed investigation of the basins in conjunction with the development of the modelling software will: 1) help to elucidate the relative importance of global theories regarding the subsidence of deep intra-continental sedimentary basins; and 2) provide a diagnostic tool in the preliminary investigation as regards the effects of these processes on depocentre-migration and hydrocarbon generation.

AAPG Search and Discovery Article #90909©2000 AAPG Foundation Grants-in-Aid