Composition and provenance of Cenozoic siliciclastic depositional systems supplying the Eastern Black Sea

Reservoir quality is a key uncertainty for hydrocarbon geologists in the Black Sea. Petrographic data from the proximal, onshore components of depositional systems that supplied the Eastern Black Sea have been analysed in Georgia, Russia and Ukraine. Sandstone compositions vary from quartz arenites with ~95% quartz to lithic arenites with up to 90% volcanic rock fragments. These data can help delineate depositional systems with differing reservoir potentials, although it is only when they are integrated with sediment provenance studies that a thorough assessment can be made. For instance, once the sediment source area for a particular depositional system has been established, field observations and analysis can constrain likely variations in sediment flux from this source area and thus its relative importance within the Eastern Black Sea basin fill through time.

In the Eastern Black Sea region, three main source areas have been identified that were capable of supplying quartz-rich sediments during the Cenozoic; the Russian Platform, western Greater Caucasus and Dziruli Massif. These have been distinguished by field mapping and sedimentological analysis, standard heavy mineral analysis, single mineral grain geochemistry and U-Pb zircon dating. Furthermore, the controls on variations in sediment composition derived from the western Greater Caucasus have been investigated through the analysis of reworked palynomorphs. This indicates that different stratigraphic units were reworked along the length of the range during Greater Caucasus Basin inversion.

Provenance work is ongoing in Turkey, Bulgaria and Romania in order to expand the geographic scope of this research.