Review of the Cretaceous-Paleogene tectonic evolution of the Black Sea. A new kinematic model in a transtensional Back-arc context

Abstract

The complex geodynamic evolution of the Black Sea as of yet has not been resolved in a way to fine-tune our understanding of the regional petroleum systems. The Black Sea region is part of the southern limit of Baltica and while there is some general agreement on the major periods of extension and inversion, underlying kinematics that drive these processes, are still controversial.

Here we propose a new kinematic model based on the review and integration of published data with gravity and density maps, 2D regional seismic interpretation, new field observations and palaeogeographic reconstructions fully explained by Iwaniw et al. 2015 (this volume).

It is proposed that the transform faults crossing Dobrogea and Predobrogea region are closely related to the NW-SE Tornquist-Tesseyre line. The latter structure resulted from the opening of the Tornquist Sea during the late Proterozoic and the subsequent Palaeozoic suture has related strike-slip faults at the Eastern Coast of the Black Sea including the Vaslui, Trotus, Saint Gheorghe, Pecenega-Camena, Capadivia-Ovidiu and Intramoesia Faults.

On the Odesa platform the general fault trend is deflected to the North and delineates a regional release bend-fault zone during the NW-SE extension in lower Cretaceous Times which will be responsible for the transtensional opening of the Karkinitsk Trough. In Romania and on the Bulgarian shelf the NW-SE trending faults crosscut NE-SW trending faults and create a zone of compartmentalized basins.

It seems unlikely that the Proterozoic/Palaeozoic plate-boundary is discontinued in the Black Sea region. In fact, the underlying structures are readily identified in the basement of the Black Sea and we suggest that their tectonic heritage played a significant role in the Mesozoic and Cenozoic tectonic evolution of the region.

The back-arc extension during the Early Cretaceous in the Black Sea area; induced by the northward subduction of NeoTethys plate below the Pontides arc partly follow existing Palaeozoic WNW-ESE trending structures including the Pecenega-Camena, Capadivia-Ovidiu and Intramoesia Faults. Back-arc extension also follows the NNW-SSE trend delineated by the Western Black Sea and West Crimea faults.

Based on the above, we propose the following structural evolution: 1) the Western Black Sea Basin opened in the Aptian-Albian in a NW-SE sinistral transtensional back-arc context and was controlled by WNW trending transform faults. 2) The Eastern Black Sea Basin opened through N-S extension with a final stage of anticlockwise rotation north of the Eastern Pontides. 3) The northern Black Sea basins opened as a consequence of a regional release bend-fault zone. 4) Cenozoic inversion is related to a regional NW-SE compression which induced dextral transpression in the Odesa Platform, Azov Sea, Great Caucasus and northern Pontides.

AAPG Datapages/Search and Discovery Article #90226 © 2015 European Regional Conference and Exhibition, Lisbon, Portugal, May 18-19, 2015