Late Pleistocene and Holocene sea-level change and coastal paleoenvironment evolution along the Iranian Caspian shore

• Published in: Marine geology 2015-03, Vol.361, p.111-125
• Main Authors: Kakroodi, A.A., Leroy, S.A.G., Kroonenberg, S.B., Lahijani, H.A.K., Alimohammadian, H., Boomer, I., Goorabi, A.
• Format: Article
• Language: English
• Subjects: Caspian Sea; Coastal; Corners; Deposition; Diatom; Holocene sea-level change; Marine environments; Marine geology; Pollen; Rapid sea-level change; Sediments; Shells
• ISSN: 0025-3227; 1872-6151
• DOI: 10.1016/j.margeo.2014.12.007

The level of the Caspian Sea is influenced by rivers mostly from the high latitudes of the Northern hemisphere and therefore any change of its catchments including temperature and precipitation directly reflects on Caspian Sea-level. We reconstructed Late Pleistocene to Holocene Caspian Sea-level by a multi-disciplinary approach from a 27.7m long core in the SE corner of the Iranian Caspian coast in the Gomishan Lagoon. Late Pleistocene deposits containing typical Pleistocene fauna and dated around 20,120calyrBP bordered with a major hiatus indicating sea-level fall. Lagoonal deposits with shells dated at around 10,590calyrBP suggest that, after this deep lowstand, an initial transgression started, leading to landward advance of barrier–lagoon systems which still continued without any lowstand until 8400calyrBP. This corresponded to a biofacies change from lagoonal to the deeper biofacies including diatom and Gastropoda species. Around 8400calyrBP sea-level started to fall again, and reddish oxidized sediments with abundant foraminifera (Ammonia beccarii) record a regressive phase around 7700calyrBP. The mid-Holocene between 15.7 and 4.9 depths is characterized by a shallow marine environment mostly with high carbonate and gypsum contents, and lagoonal and highstand tract with no subaerial facies. The upper part of the core above a 4.9m depth reflects at least five Late Holocene Caspian Sea-level cycles from 3260calyrBP onward. The Caspian Sea-levels are influenced both by global and regional events. •Similar deposits have been found between the Caspian Sea and the Black sea in the Late Pleistocene.•Caspian Sea level experienced a deep lowstand between the boundary of Pleistocene and Holocene.•The Caspian Sea was at its maximum level between around 10,500 and 8400calyrBP.•Five Holocene sea level cycles have been identified commencing at 3255calyrBP.•Caspian Sea levels are influenced by global factors as its catchments extend over the Northern hemisphere.