Holocene relative sea-level changes in the eastern part of Pomeranian Bay and the Szczecin Lagoon, Southern Baltic Sea

Abstract

Sea-level changes of the Baltic Sea have been in the focus since the beginning of Baltic history studies. The main goal of the study is to reconstruct Holocene sea-level changes in the eastern part of Pomeranian Bay and the Szczecin Lagoon. For this purpose, 171 radiocarbon dates were used for the eastern part of Pomeranian Bay and 131 radiocarbon dates for the Szczecin Lagoon. The data allow reconstructing sea-level changes in the last 8500 years in the eastern part of Pomeranian Bay and 7500 years in the Szczecin Lagoon. The sea level 8500 yr b2k was ca. 16 m in Pomeranian Bay, while 7500 yr b2k in the Szczecin Lagoon, it was ca. 8 m below the present sea level. Initially, the fast sea-level rise (up to 9.0 mm/yr) slowed down about 6000 yr b2k to ca. 1.0 mm/yr. In the last 5000 years, the sea level rose at a rate of 0.5 mm/yr in both sites. Analysed data allow distinguishing an extreme event (or events) that disturbed a rather regular course of sea-level rise, which occurred between 7314 and 7022 yr b2k. The history of sea-level changes was similar in the eastern part of Pomeranian Bay and the Szczecin Lagoon despite differences in the geological structure of the pre-Quaternary bedrock and potential various trends in vertical crustal movements. Similarities to some other regions of the southern Baltic and the world ocean allow assuming that sea-level changes in the study area in the last 9000 years in general were eustatic in nature.