ORGANIC-MATTER IN OLIGOCENE MENILITE FORMATION ROCKS OF THE UKRAINIAN CARPATHIANS - PALEOENVIRONMENT AND GEOCHEMICAL EVOLUTION

The Ukrainian Carpathians form the middle sector of the Carpathian Arc. The Menilite black shale Formation (Oligocene-Early Miocene) is the youngest part of the flysch sequence and occurs in a wide depth range. The anaerobic bacterial processes during early diagenesis led to formation of C-13-rich carbonate concretions and C-13 depleted organic matter. Black shales contain Type II kerogen with high source rock potential. In the upper 4 km of the sequence the rocks preserved their pre-overthrusting level of maturity (close to the beginning of the oil window), while at greater depths the maturity increases under the influence of present day heat flow.