Existence and Distribution of Basin-Wide Strike Slip Fault Systems in an Asymmetrical Back Arc Rift System: The Black Sea Basin

The Black Sea Basin has been a focus of interest due to its economically promising hydrocarbon reserves and complex tectonic history. Several different theories were proposed to decipher its enigmatic basin formation and tectonic evolution processes.

One important characteristic of the Black Sea Basin that makes it unique is its isolation from the world oceans, and global sea level changes for long periods during the geological time. This provides a good realm to correlate tectonic episodes with rapid sedimentation patterns in its thick sedimentary section. With the aim of modelling this sequence of events, we reviewed and reinterpreted previously proposed scenarios. We focus on the back-arc rifting and subsequent tectonic inversion that led the surrounding mountain belts to form. By reinterpreting 24 long-offset 2D seismic lines acquired by GWL in 2011, we propose a new structural framework for the Black Sea Basin.

Our structural geology analyses show that in addition to basin-bounding normal faults and inversion tectonics, numerous flower structures occur in both the western and eastern Black Sea subbasins. These flower structures are typical indicators of strike-slip fault systems and in the Black sea Basin case, the orientation of these fault systems is roughly east-west. Our interpretations align with the hinge model that Stephenson and Schellart (Geological Society London Special Publications, 2010) proposed to explain the opening of the Black Sea Basin as one basin rather than the conventional interpretation of a two separate rifted basin configuration. The proposed tectonic framework sheds light on the geometry of the Black Sea Basin’s bounding faults, complex faulting and folding recognized in the sedimentary section, and complex ridge-depression geometry.