+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Two deltas, two basins, one river, one sea; the modern Volga delta as an analogue of the Neogene productive series, South Caspian Basin



Two deltas, two basins, one river, one sea; the modern Volga delta as an analogue of the Neogene productive series, South Caspian Basin



Special Publication - Society for Sedimentary Geology 83(Pages 231-256



The Neogene Productive Series, the main reservoir unit of the prolific hydrocarbon province in the South Caspian Basin, and the modern Volga delta in the northern Caspian Sea, are deltas deposited by the same river into the same closed sea. Both deltas are lowgradient, mud-dominated, river-dominated, multichannel, ramp deltas without a shelf break, and show the impact of rapid changes in sea level, climate-driven discharge, and sediment input. But there are also prominent differences. The Productive Series forms the lowstand wedge of the most dramatic sea-level fall the Caspian has ever experienced. It consists of a succession, up to 7 km thick, of fluviodeltaic sediments, deposited at extremely high sedimentation rates (2-4 mm/y) by a paleo-Volga River in the narrow, rapidly subsiding South Caspian basin. Simultaneously, the paleo-Volga carved a canyon 2000 km long and up to 600 m deep far upstream into the Russian plain. The smaller Kura and Amu Darya rivers also contributed to the Productive Series. The sedimentary succession in the proximal part of the Productive Series shows the transition from an alternation of sheetflood sandstones and floodplain mudstones with great lateral continuity to finer-grained packages in which coarsening-upwards facies successions are common and there is evidence of repeated emergence and desiccation. A coarser-grained interval reflects increasing uplift in the adjacent Greater Caucasus mountains. The upsection increase in mud-dominated deposition in the Productive Series is thought to reflect a trend towards more humid climates. The modern Volga delta is not more than 20 m thick and has been deposited during the last 6000 years on a wide stable continental platform at a level halfway between a major Last Glacial highstand and a deep Early Holocene lowstand. It shows rapid lateral and vertical facies changes at the delta front, and it is characterized by many small radial sand bodies with low connectivity, coarsening-upwards mouthbar and levee deposits overlying clayey prodelta deposits, and fining-upwards channel fills. There is evidence of frequent emergence and submergence due to rapid sea-level changes. Average sedimentation rates are lower than in the Productive Series (0.7-1 mm/y in uncompacted muds). The reasons for the differences are threefold. Sedimentation in the Productive Series spanned two million years, but in the modern Volga delta less than 6,000 years, so the latter cannot be more than a partial analogue of the former. The outcropping sediments of the Productive Series were deposited in a more proximal position than the studied sediments of the modern Volga delta front, which may partly explain the difference in lateral continuity of the sandy successions. But above all the paleo-Volga shed its load in a narrow, rapidly subsiding basin, whereas the present Volga spreads its sediment across a wide and shallow stable continental platform. The differences in basin geometry and dynamics explain part of the differences in 3-D architecture and sedimentation rates.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 020528376

Download citation: RISBibTeXText


Related references

Fluvial sedimentology of the Neogene productive series, Azerbaijan; implications for reservoir quality and exploration in the South Caspian Basin. Annual Meeting Expanded Abstracts - American Association of Petroleum Geologists 2002(Pages 77, 2002

Fluvial sedimentology of the Neogene Productive Series, Azerbaijan; implications for reservoir quality and exploration in the South Caspian Basin. Open File Report University of Nebraska Lincoln, Conservation and Survey Division: 125. 2001., 2001

Fluvial sedimentology of the Neogene productive series, Azerbaijan; implications for reservoir quality and exploration in the South Caspian Basin. Annual Meeting Expanded Abstracts - American Association of Petroleum Geologists 2002(Pages 77, 2002

Contrasting Pliocene fluvial depositional systems within the rapidly subsiding south Caspian Basin; a case study of the palaeo-Volga and palaeo-Kura River systems in the Surakhany Suite, Upper; Productive Series, onshore Azerbaijan. Marine and Petroleum Geology 27.10, 2010

The paleo-Volga Delta and lacustrine sequence stratigraphy of the South Caspian Basin. The Bulletin of the Houston Geological Society 41(8): 14-15, 1999

Climate-controlled sedimentary architecture of the paleo-Volga Delta in the South Caspian Basin. Annual Meeting Expanded Abstracts - American Association of Petroleum Geologists 2001(Pages 145, 2001

Reservoirs of the lower Pliocene productive series at the western flank of the South Caspian Basin. Lithology and Mineral Resources 40(3): 267-278, 2005

Reservoirs of the lower Pliocene productive series at the western flank of the South Caspian Basin. Lithology and Mineral Resources 40(3): 267-278, 2005

Provenance of clay minerals in the sediments from the Pliocene Productive Series, western South Caspian Basin. Marine and Petroleum Geology 73: 517-527, 2016

Investigation of the ecology of arboviruses in river deltas of the Caspian and Azov Sea basins. 1971

Estimation of free and bound water balance in productive series Ps within the western part of south Caspian Basin. Annual Meeting - American Association of Petroleum Geologists, 2009

Deltas at rapidly changing sea level; the Recent and Pliocene Volga deltas in the Caspian Sea. Abstracts with Programs - Geological Society of America 34(6): 482, 2002

Natural lands of northern Caspian coasts and Volga and Ural river deltas as habitat of waterfowl in the end of XX century. Trudy Instituta Zoologii - Almaty 48: 228-259, 2004

Sedimentology, stratigraphy, petrography of mid-Pliocene Productive Series, Azeri Field offshore Azerbaijan south Caspian Basin. Annual Meeting - American Association of Petroleum Geologists, 2008

Migrations of birds of river deltas of the Azov and Caspian Basins and their possible role in the transportation of arboviruses. Unknown, 1975