Current sequence stratigraphical principles are based on large-amplitude sea-level oscillations (tens-hundreds of metres) on 3rd to 5th order time scales (millions to hundreds of thousands of years) in basins open to eustatic sea-level changes. Our central question is: Can sea-level cycles of smaller amplitude (metres) and time scales (decades, centuries, millennia), as evidenced from closed basins like the present-day Caspian Sea, be resolved in the sedimentary record? And if so, what are their specific characteristics? The study focuses on deltaic sequences in the Productive Series on the Apsheron Peninsula (Azerbaijan), deposited by a Paleo-Volga in the Lower Pliocene, after the closure of the Caspian Sea in the Messinian. Small-scale sea-level cycles in these Series will be investigated by comparison with the well-monitored sedimentary dynamics in the modern Volga Delta (Russia) during the last Caspian sea-level cycle (1929-1995 AD) and with Holocene sedimentary sequences in the modern Volga delta, which by C14 dating can be coupled to the Holocene sea-level oscillations.
The project comprises studies of the geometry and chronology of modern and Holocene Volga delta sedimentary sequences, using remote sensing, augering, shallow seismics, existing hydrological data and process-response modelling. Seismic, sedimentological, geochemical, bio- chrono- and chemostratigraphic data of the Paleo-Volga will be assembled and integrated with new insights arising form modern Volga studies into a 3-D geological model using up-to-date Geoframe and STORM/IRAP software.
As a result of the project we will be able to make considerable improvements in the interpretation of the 3-D geometry of the Productive Series, thus far only interpreted in terms of global eustasy. This will lead to a better understanding of the 3-D geometry of hydrocarbon occurrences in the South Caspian Basin and target new areas for exploration. It will lead as well to a better understanding of the architecture of sediment wedges in closed basins elsewhere in the geologic record, which must have existed in many closing oceans before continental collision (Iapetus, Tethys). At last it will lead to better understanding of rapid sea level change in the Caspian Sea, which is of utmost importance, both as a component of global climate change, and for environmental protection and coastal management of Caspian shores.
AB24 3UE Aberdeen