Mid-Holocene paleoceanographic conditions in the Limfjord region from gastropod (Littorina littorea) oxygen and carbon isotopes
Abstract
Stable oxygen and carbon isotope intrashell transects of common intertidal gastropods Littorina littorea have been used to reconstruct environmental conditions in the Limfjord region during the mid-Holocene (late Atlantic time). The subfossil specimens studied are from the excavated Stone Age Kitchenmidden in Ertebølle, northern Denmark, dated between 5970±95 to 5070±90 B.P. In addition recent specimens were studied from different coastal localities within the Limfjord, along a salinity gradient from the west to east. These modern shells were used as control samples, in order to construct an oceanographic model for the Limfjord, in which the seasonal isotopic range from the Littorina subfossils could be interpreted. The coastal marine climate in the Ertebølle region during the mid-Holocene indicates summer-SST close to 22^oC and 4-5 ppm reduced salinity compared to fully marine conditions. The mid-Holocene central Limfjord can be described as a coastal area, which experienced similar salinity conditions (c. 30.5 PSU) that prevail in the western part (Odden area) today. In terms of summer-SST as compared with a 10-year average (1989-1998) for the Limfjord region, temperatures were 2-3^oC above recent climatic settings. These results point towards a mid-Holocene Limfjord in contact with the North Sea/Skagerrak with possibly more pronounced water exchange with the North Sea than today.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA....14193B