Fruergaard, Mikkel

Johannessen, Peter N.

Morigi, Caterina

Nielsen, Lars Henrik

Pejrup, Morten

Sander, Lasse

English

Copenhagen University Research Information System

u n i ve r s i t y  o f  co pe n h ag e n  Københavns UniversitetCoastal lagoon systems as indicator of Holocene sea-level development in aperiglacial soft-sediment setting: Samsø, DenmarkSander, Lasse; Fruergaard, Mikkel; Johannessen, Peter N.; Morigi, Caterina; Nielsen, LarsHenrik; Pejrup, MortenPublished in:Geophysical Research AbstractsPublication date:2014Document versionEarly version, also known as pre-printCitation for published version (APA):Sander, L., Fruergaard, M., Johannessen, P. N., Morigi, C., Nielsen, L. H., & Pejrup, M. (2014). Coastal lagoonsystems as indicator of Holocene sea-level development in a periglacial soft-sediment setting: Samsø, Denmark.Geophysical Research Abstracts, 16, [6890].Download date: 03. Feb. 2020Geophysical Research AbstractsVol. 16, EGU2014-6890, 2014EGU General Assembly 2014© Author(s) 2014. CC Attribution 3.0 License.Coastal lagoon systems as indicator of Holocene sea-level development ina periglacial soft-sediment setting: Samsø, DenmarkLasse Sander (1,2), Mikkel Fruergaard (1), Peter N. Johannessen (2), Caterina Morigi (2,3), Lars Henrik Nielsen(2), and Morten Pejrup (1)(1) Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark, (2) GeologicalSurvey of Denmark and Greenland (GEUS), (3) Department of Geosciences, University of Pisa, ItalyConfined shallow-water environments are encountered many places along the coast of the inner Danish waters.Despite their common occurrence, these environments have rarely been studied as sedimentary archives. In thisstudy we set out to trace back changes in relative sea-level and associated geomorphological responses in sedimentcores retrieved from coastal lagoon systems on the island of Samsø, central Denmark.In the mid-Atlantic period, the post-glacial sea-level rise reached what is today the southern Kattegat Sea. Waves,currents and tides began to erode the unconsolidated moraine material and melt-out deposits. This initiatedsedimentation in adjacent coastal lagoons and further supported the formation of coastal barriers. Until presentday, the ongoing isostatic uplift caused a continuous drop of relative sea-level resulting in shoreline accretion andsuccessive lagoonal infilling.Stratigraphy, grain-size distribution, fossil and organic matter content of cores retrieved from the lagoons wereanalyzed and compared. Age control was established using radiocarbon and optically stimulated luminescencedating.Our data produced a surprisingly consistent pattern for the sedimentary successions found in the lagoons. Theperiod of initial transgression can be identified as the onset of deposition of fine-grained, organic-rich sediments.However, radiocarbon dates evidence a punctuation of these deposits further upcore. Grain-size analysis suggeststhat the reworking and abrasion of the lagoon sediments resulted from the gradual lowering of the wave-base.The core sequence is topped-off by marine sands and wind-blown deposits. Based on these findings, we suggesta conceptual model that allows inferring age and elevation of transgressive and regressive stages from the lagooncores.The common occurrence of similar environments distributed along gradients of isostatic uplift/subsidence(approximately +0,5 to -0,5 mm/yr) in the south-western Baltic, makes coastal lagoon systems a valuable archivefor the reconstruction of Holocene sea-level and coastal evolution.

Coastal lagoon systems as indicator of Holocene sea-level development in a periglacial soft-sediment setting: Samsø, Denmark

https://curis.ku.dk/portal/files/140582927/EGU2014_coastal_lagoons.pdf

Coastal lagoon systems as indicator of Holocene sea-level development in a periglacial soft-sediment setting: Samsø, Denmark

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