Short- and Long-Term Development of the Miankaleh Spit, Southeast Caspian Sea, Iran

Abstract

Kakroodi, A.A.; Kroonenberg, S.B., and Naderi Bonab, M. 2014. Short- and long-term development of the Miankaleh Spit, southeast Caspian Sea, Iran.The development of the 60-km-long Miankaleh Spit in the southeastern corner of the Caspian Sea has been studied in two different timescales. At the start of the twentieth century 3 m sea-level cycle, the spit already existed, but it emerged prominently during the lowstand in the late 1970s, and drowned and fell apart into several islands during the following highstand that culminated in 1995. The analysis of core data and sedimentological analyses (grain size, biofacies, carbonate content, heavy mineral, and magnetic susceptibility) show that the Miankaleh Spit and the Gorgan Bay did not yet exist during the well-known 2600–2300 cal. YBP highstand, and at that time waves and longshore currents deposited barrier systems along the mainland coast. During the lowstand, deltas from rivers draining the eastern Alborz Mountains extended much more westward than at present. It was only during the last major highstand in the Little Ice Age that the present-day Miankaleh Spit was formed by eastward progradation caused by strong longshore currents.