Integrated sedimentology and organic geochemistry of world-class source rocks in the Black Sea
thesisposted on 10.09.2021, 13:26 by Michael T. Morton
The Eocene Kuma Formation and Oligocene - Miocene Maikop Group are marine mudstones and source rock components of Black Sea petroleum systems. The Kuma Formation was deposited in the Peri-Tethys realm a the northern margin of the Tethys Ocean whilst the Maikop Group was deposited later in the younger Paratethys, a partially disconnected seaway further isolated during Arabia-Eurasia collision and Greater Caucasus uplift, and by Oligocene regression. The Maikop Group has been extensively studied for its source rock potential with fewer studies conducted on the Kuma Formation. While there are published geochemical data on these rocks, there are no studies to date that have analysed their sedimentological facies, processes or depositional environment, and their link with organic carbon burial. This thesis presents the first detailed sedimentological study of the Kuma Formation and Maikop Group by; 1) identifying and interpreting microlithofacies through thin section petrography; 2) conducting organic geochemical analysis of the Kuma Formation to produce the first dual data set for source rock characterisation; and, 3) undertaking strontium isotope analysis to determine basin connectivity. The investigation into the Kuma Formation and Maikop Group sedimentology reveals a wide variety of sedimentary processes in a dynamic depositional environment that verifies interpretations in previous studies and offers novel insights into the marginal marine setting of the Paratethys during the Early Cenozoic. Both intervals are summarised to be of good source rock quality with the Kuma Formation in particular demonstrating a variety of sedimentological facies that all contain preserved organic material and have good hydrocarbon potential. This thesis illustrates the wealth of understanding that can be gained from studying mudstones at the microscale and offers insights into the relationship between depositional history and environments, and source rock production. Indeed, source rocks can be deposited under a variety of conditions and not uniformly stratified and anoxic.