The first geological record of a palaeotsunami on the southern coast of the Baltic Sea, Poland

Authors

  • Karol Rotnicki 1-University of Szczecin, 2-Adam Mickiewicz University in Poznań
  • Joanna Rotnicka Adam Mickiewicz University in Poznań
  • Tomasz Goslar 1-Adam Mickiewicz University in Poznań, 2-Poznań Radiocarbon Laboratory
  • Brygida Wawrzynniak-Wydrowska University of Szczecin

DOI:

https://doi.org/10.7306/gq.1294

Keywords:

Baltic Sea, onshore tsunami deposits, age of tsunami, Holocene coastal changes, meteorite impact

Abstract

Tsunami deposits were unknown along the southern coast of the Baltic Sea for a long time. The results of present research provided evidence of high-energy event layers. They occur on the bottom of two hemispherical hollows that are cut into glaciolimnic silt and glaciofluvial sand and gravel from the Late Weichselian Age. The event deposits are represented by poorly sorted marine sand with admixtures of pebbles and allochthonous detritus of biogenic origin: marine, brackish and occasionally freshwater shells and shell debris of molluscs and snails, plant macrofossils from the marine nearshore zone, shreds and lumps of peaty material, gyttja and organogenic silt, lumps of charcoal, wood pieces and tree branches and trunks. All these features are commonly considered indicative of tsunamis. The age of the biogenic detritus found in the tsunami layer ranges from 10 390 to 6 630 cal. yr BP, whereas the oldest gyttja covering the event layers is 6 600 cal. yr BP old. This means that the tsunami occurred between 6 630 and 6 600 cal. yr BP. Various causes of tsunami event have been taken into consideration, including the impact of meteorites within the coastal plain and the littoral zone of the southern Baltic Sea.

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Published

2016-05-13

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Section

Thematic issue