A Holocene sea-level database for the Baltic Sea

• Main Authors: Bagge Meike, Bennike Ole, Berglund Mikael, Bitinas Albertas, Clemmensen Lars B., Grudzinska Ieva, Hansson Anton, Hede Mikkel U., Klemann Volke, Kroon Aart, Kubilitskiy Yuriy, Lampe Matthias, Lampe Reinhard, Latinović Milena, Nielsen Lars, Nigri Triine, Ojala Antti, Pejrup Morten, Peterson Becher Gustaf, Rosentau Alar, Sander Lasse, Schoning Kristian, Schwarzer Klaus, Stattegger Karl, Steffen Holger, Subetto Dmitry, Uścinowicz Szymon, Vassiljev Jüri, Wehr Jasmin
• Other Authors: geologia, Geology, 2606902
• Language: English
• Published: Elsevier Ltd 2022
• Subjects: Ice Sheet
• Online Access: https://www.utupub.fi/handle/10024/164616; https://www.sciencedirect.com/science/article/pii/S027737912100278X?via%3Dihub

Abstract We present a compilation and analysis of 1099 Holocene relative shore-level (RSL) indicators located around the Baltic Sea including 867 relative sea-level data points and 232 data points from the Ancylus Lake and the following transitional phase. The spatial distribution covers the Baltic Sea and near-coastal areas fairly well, but some gaps remain mainly in Sweden. RSL data follow the standardized HOLSEA format and, thus, are ready for spatially comprehensive applications in, e.g., glacial isostatic adjustment (GIA) modelling. We apply a SQL database system to store the nationally provided data sets in their individual form and to map the different input into the HOLSEA format as the information content of the individual data sets from the Baltic Sea area differs. About 80% of the RSL data is related to the last marine stage in Baltic Sea history after 8.5 ka BP (thousand years before present). These samples are grouped according to their dominant RSL tendencies into three clusters: regions with negative, positive and complex (transitional) RSL tendencies. Overall, regions with isostatic uplift driven negative tendencies dominate and show regression in the Baltic Sea basin during the last marine stage. Shifts from positive to negative tendencies in RSL data from transitional regions show a mid-Holocene highstand around 7.5–6.5 ka BP which is consistent with the end of the final melting of the Laurentide Ice Sheet. Comparisons of RSL data with GIA predictions including global ICE-5G and ICE-6G_C ice histories show good fit with RSL data from the regions with negative tendencies, whereas in the transitional areas in the eastern Baltic, predictions for the mid-Holocene clearly overestimate the RSL and fail to recover the mid-Holocene RSL highstand derived from the proxy reconstructions. These results motivate improvements of ice-sheet and Earth-structure models and show the potential and benefits of the new compilation for future studies.