A new perspective on the Cenozoic evolution of the Arabia-Black Sea-Greater Caspian: insights from global plate tectonic modelling
During the Cenozoic, the area located at the junction of the Turkish, Caspian, Black Sea and Arabian plates records the closure of the residual segments of the Neotethys and the ongoing Alpine-Himalayan Collision. The geodynamic and kinematic history of this region is of a considerable importance for hydrocarbon exploration as it is critical for understanding the evolution of prolific mature hydrocarbon provinces, such as the Mesopotamian basin and the Western Caspian, along with promising frontier regions such as Kurdistan or the North East Black Sea.
In detail, this area represents a complex tectonic setting where several branches of the Neotethys closed successively between micro-continental blocks. The regional geodynamic evolution and the timing and total deformation of the different parts of the orogen are still debated. The use of a global geodynamic plate model provides accurate constraints to pin the boundaries of the system (i.e. the Eurasian and the Arabian Plate) and to discriminate between the different regional models.
The workflow we have used to revise the geodynamic evolution of this region includes 1) a tectono-structural review, resulting in a more accurate definition of the terranes 2) a redefinition of the isochrons in the Atlantic Ocean, Indian Ocean and Gulf of Aden, in order to accurately constrain the relative locations the major continental plates of Arabia, Africa, Eurasia and India, 3) the incorporation of multi-disciplinary data including geochronology, mineral deposits and sedimentary evidence, 4) integration of these elements with a regional knowledge and insight from the literature to redefine the kinematic (rotation poles) and tectonic (plate boundaries) evolution within a consistent global geodynamic framework.
As an illustration, closure of all oceanic domains between Arabia and the Trans-Caucasus terrane was achieved by the Early Oligocene (e.g. Jaffrey and Robertson, 2005; Oberhansli et al., 2010; Sosson et al., 2010), but regional convergence between Arabia and Eurasia continued during the Neogene. The globally constrained positions of Eurasia and Arabia during the Neogene provide an independent estimate of the magnitude of convergence between these plates that is consistent with regional estimates (e.g. Mouthereau et al., 2012). Limited shortening on the northern Arabian margin during the Neogene (e.g. Robertson et al., 2007) implies that most of the convergence between Arabia and Eurasia was accommodated in the Caucasus (Saintot et al., 2006; Mosar et al., 2010; Meisner et al., 2009). This compression can be modelled by rotation of a Black Sea Plate around an Euler pole located in the Western Black Sea. A consequence of this rotation is the inference of a trans-tensional regime on the western boundary of this Black Sea Plate; this motion provides a possible mechanism for the right-lateral offset of the eastern tip of the Balkan Fold-Thrust Belt observed in offshore Bulgaria (e.g. Doglioni et al., 1996).
This example demonstrates how this work results in a new consistent and more precise global geodynamic model that can be used to assess the tectonic evolution of complex regions. The insights gained from this model allow us to make better predictions of paleo-topography, timing of deformation, depositional systems and facies distribution, thus providing an improved understanding of regional petroleum systems.
AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015