A continuous marine record 8000-1600 cal. yr BP from the Malangenfjord, north Norway: foraminiferal and isotopic evidence

Abstract

Holocene oceanography and climate were studied in the continuous marine sediment sequence in a piston core from the high-latitude Malangenfjord, north Norway, using benthic foraminifera and stable isotopes. Radiocarbon dates indicate that the investigated sequence covers the period from c. 8000 to 1600 cal. BP and has a sedimentation rate of 0.3-12.7 m/1000 years. Bottom-water temperatures reconstructed from benthic foraminiferal stable isotopes in the Malangenfjord show a cooling of c. 3°C ranging from 10°C and reaching c. 7°C at 1600 cal. yr BP which is similar to present bottom-water temperature at the core location. A planktic foraminiferal °18O record was established from c. 6400 to 1600 cal. yr BP generally following the same pattem as the benthic record. This long-term cooling correlates to the decreasing insolation at 70°N following the orbital forcing. The long-term cooling also corresponds well with atmospheric proxy records implying a close ocean-atmosphere coupling. It is also indicated both by marine and atmospheric temperature and precipitation proxy records that the climate was more oceanic during the early Holocene. Several cold events are interpreted as decreased influence of Atlantic Water in the fjord.