Comparison of Meso-Cenozoic Tectonic Subsidence of Odessa Shelf and Azov Sea, Ukrainian Offshore

Khriachtchevskaia, Oxana I.¹, Sergiy M. Stovba¹, Randell A. Stephenson² (1) Scientific Research Institute of Oil and Gas Industry of National Joint-Stock Company “Naftogaz of Ukraine” (“Naukanaftogaz”), Kyiv, Ukraine (2) Vrije Universiteit, Amsterdam, Netherlands

The evolution of the Ukrainian offshore - Odessa Shelf (NW Black Sea) and Azov sea was studied using seismic/well data. Three stages of the Meso-Cenozoic tectonic history of Odessa shelf were revealed from seismic data: rifting due to extension (Early Cretaceous – earliest Late Cretaceous); post-rift thermal subsidence (middle Late Cretaceous - Middle Eocene); inversion (Late Eocene – Middle Miocene). 1D backstripping and forward model­ling was applied to confirm these stages. The modelling results clearly demonstrate the stages of tectonic evolution of the Odessa shelf and specify their age: rifting (middle Early Cretaceous – Santonian) with delta factor of 1.13; the post-rift thermal subsidence (Campanian – Middle Eocene) with delta factor of 1.0; the compression with delta factor of

0.9 (Late Eocene – Middle Miocene).

The modelling results demonstrate only two stages of tectonic evolution of the Azov sea: rifting (Albian) with delta factor of 1.05; post-rift thermal subsidence (Late Cretaceous – Eocene) with delta factor of 1.0. Tectonic events during Oligocene-Early Miocene within the Azov sea very likely connected with the formation of the Indolo-Kuban Foreland of the Great Caucasus. The normal post-rift subsidence that existed during Late Cretaceous – Eocene, was reestablished after Early Miocene. Thus, the tectonic evolution of the Odessa shelf had only some resemblance to the one of the Azov sea in the Cretaceous – Eocene time as we can recognise the same stages of their tectonic history. The rift stage of the Azov sea com­pleted earlier than it happened within the Odessa shelf.