Surface ocean properties of the Norwegian Sea during MIS5e, based on dinoflagellate cysts and foraminiferal assemblages

• Main Authors: Van Nieuwenhove, Nicolas, Bauch, Henning, Matthiessen, Jens
• Format: Conference Object
• Language: unknown
• Published: GEUS 2006
• Subjects: Arctic; Norwegian Sea; Foraminifera*; Iceberg*; Nordic Seas; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/8177/

The Nordic Seas are considered to be a crucial area in terms of climate-regulating processes. Although the last interglacial, Oxygen Isotope Stage 5e (OIS5e), is regarded as an analogue for Holocene climate, detailed dinoflagellate cysts studies have not been done on OIS5e from this region. Here, the well-established relation between dinoflagellate cyst assemblages and sea-surface parameters for the (sub)Arctic is applied on the last interglacial section using a sediment core from the eastern Norwegian Sea. Considering the long-term climate trend, combined data of foraminifers, dinoflagellate cysts and iceberg-rafted debris (IRD) indicate that proper, peak interglacial conditions occurred only during the later phase of OIS5e, and only after IRD-input and, thus, surface freshening had come to an end. While dominance of Operculodinium centrocarpum indicates that inflow of warm North Atlantic water persisted in the area throughout this climatically optimal period, short-term fluctuations in the dinoflagellate cyst assemblages show that, oceanographically, the climatic optimum was not a period of entire stability. Moreover, like in the South-Icelandic basin (Eynaud et al., 2004), we find a relative abundance peak of Spiniferites mirabilis in the Norwegian Sea at the very end of the IRD-free interval. This finding denotes the occurrence of warmest surface waters during the latest phase of the last interglacial, just before the transition towards the much colder stadial OIS5d.