Structure of the South-Western Part of the Curonian Spit

This article addresses the southern sector of the Curonian Spit, the largest coastal barrier of the Baltic Sea. A comparative analysis of the deposits that make up parts of the Curonian and Vistula Spits is given. The detailed analysis of the geological and geomorphological structure of the southern part of the Curonian Spit suggests that, within this sector, it is not a sedimentary barrier created by wave action and Aeolian processes in the Holocene, but a part of a pre-Holocene fluvioglacial plain. Field work has shown that the ancient alluvial or fluvioglacial plain is in the lagoon shore of the Vistula Spit

SOLAR-FORCED 2600 BP AND LITTLE ICE AGE HIGHSTANDS OF THE CASPIAN SEA

The researches combining a social, economic and ecological content, find out a generality of appendix area and global purpose. This purpose image is hidden behind the term sustainable development". These restrictions are presented as the multiplicative index of the development. This index is reflecting an information balance of a territory.The level of the Caspian Sea, the largest inland sea in the world, has fluctuated capriciously in history, with amplitudes up to 3 m in the last century, to 25m in the last millennium, and to over 150m since the Last Glacial. The results suggest that the last major highstands occurred around 2600 BP and in the Little Ice Age and coincide with global cooling events associated with minima in solar activity. This suggests that millennial precipitation changes in the Volga River drainage basin are also forced by solar activity

Two deltas, two basins, one river, one sea. The modern Volga Delta as an analogue of the Neogene Productive Series, South Caspian Basin

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 low-gradient, 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.\ud \ud 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 River Deltas -Concepts, Models, and Examples 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.\ud \ud 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

Two deltas, two basins, one river, one sea. The modern Volga Delta as an analogue of the Neogene Productive Series, South Caspian Basin

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 low-gradient, 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 River Deltas -Concepts, Models, and Examples 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