Search

The Volga Delta developed in the closed Caspian basin can be classified as a river-dominated type. The subaqueous part of the delta (avandelta) is characterized by an extremely gentle slope and may be subdivided into shallow and deep parts. The very low-angle slope of the shallow avandelta is a major factor to mitigate impacts of Caspian sealevel (CSL) changes on the Volga Delta during the last 100 years. The CSL has fluctuated 3.46 m in the last 100 years, with a high of −25.55 m relative to the Baku Datum (BD) in 1903 and a low of −29.01 m BD in 1977. Sea-level changes can be grouped into three stages: (1) slowly falling at an average rate of 1.1 cm yr−1 in 1900–1929; (2) rapidly falling at an average rate of 6.3 cm yr−1 in 1930–1977; (3) rapidly rising at an average rate of 8.8 cm yr−1 in 1978–1999. During the rapid fall stage of sea level, the Volga delta-plain expanded at a rate of 2.3 km2 yr−1 to 180 km2 yr−1 because of alluvial accumulation and exposure of the shallow avandelta. Flourishin...