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International audience; A high-resolution piston core, ENAM93-21, from a water depth of 1020 m near the Faeroe-Shetland Channel is investigated for variations in magnetic susceptibility, surface oxygen isotopes, grain size distribution, content of ice-rafted detritus (IRD), and distribution of planktonic and benthic foraminifera. The core, coveting the last 58,000 years, is correlated with the Greenland ice cores and compared with paleorecords from the Norwegian Sea and the North Atlantic Ocean. All fifteen Dansgaard-Oeschger climatic cycles recognized from the investigated time period in the Greenland ice cores have been identified in the ENAM93-21 core. Each cycle is subdivided into three intervals on the basis of characteristic benthic and planktonic faunas. Interstadial intervals contain a relatively warm planktonic fauna and a benthic fauna similar to the modem fauna in the Norwegian Sea. This indicates thermohaline convection as at present, with a significant contribution of deep water to the North Atlantic Deep Water (NADW). Transitional cooling intervals are characterized by more cold water planktonic foraminfera and ice-related benthic species. The benthic fauna signifies restricted bottom water conditions and a reduced contribution to the NADW. The peak abundance of N. pachyderma (s.) and the coldest surface water conditions are found in the stadial intervals. The benthic fauna is dominated by species with an association to Atlantic Intermediate Water, suggesting an increased Atlantic influence in the Norwegian Sea, and there was probably no contribution to the NADW through the Faeroe-Shetland Channel. The three different modes of circulation can be correlated to paleoceanographic events in the Norwegian Sea and the North Atlantic Ocean.

High-resolution magnetic analysis has been performed on the top ∼25 m of core MD99-2275 (66°33.06′N, 17°41.59′W; 440 m water depth) from the mid-outer shelf off North Iceland. This is a key boundary region for climate changes related to atmospheric and oceanographic variations influenced by the moving limit between the cold and warm water masses at the Polar Front and the low depression track with its associated westerlies situated across Iceland. An age model based on tephrochronology was previously reported for this core and has allowed precise timing of significant variations in the magnetic mineral concentration and grain size over the last 10 cal kyr. The ‘Holocene climatic optimum’ identified in North Iceland between ∼ 10 and 6 cal kyr BP is characterized by minor variations in the magnetic record, while there is a clear increase in oceanographic instability from ∼ 6 cal kyr BP to the present. At large scale, a decreasing trend in the magnetic mineral content toward the present is presumably associated with a change in the circulation pattern and coincides in time with decreasing North Atlantic Deep Water formation. Short-term intervals of decreased magnetic mineral content are also identified at 5.2–4.9, 3.77–3.41, 3.01–2.7 and 0.93–0.62 cal kyr BP, the youngest one (AD 1020 to 1330) corresponding in time to the Medieval Warm Period. These events are interpreted to reflect periods of increased activity of the relatively warm, high salinity surface Irminger Current related to stronger input of North Atlantic waters into the Nordic Seas. In addition, spectral analysis of selected magnetic parameters demonstrates centennial-scale periodicities of ∼715, 240, 170 and 100 yr, which are more clearly expressed in the last 6 cal kyr BP than in the previous period. These periodicities might be attributed to intervals of persistence in the North Atlantic Oscillation (NAO) mode at centennial timescales. This record, therefore, indicates that the Holocene climate was more unstable than is often assumed, and it demonstrates the importance of high-resolution climatic studies for this recent time period to improve climate model predictions.

In order to contribute to our understanding of the linkage between climate and ocean circulation we have studied benthic foraminifera from near the northern end of the Faeroe–Shetland Channel covering isotope stages 6 to lower stage 3 (∼150–55 ka). Our records demonstrate shifts between recurring assemblages, which on millennial timescales monitor the outflow history of Norwegian Sea Deep Water. The records show that the outflow is closely linked to the climate of the region as documented in the Greenland ice cores. Outflow was relatively strong during all major warmer interstadials whereas there was no outflow during the colder stadials. During isotope substage 5e outflow was stable for ∼10–12 kyr with significant changes at the beginning and end only.

A core from the margin of the Faeroe-Shetland Channel covering the last glacial period (58–10 ka) reveals a very detailed record of oscillations in benthic and planktic foraminifera, oxygen isotopes, and ice-rafted detritus. The oscillations correlate almost exactly with the Dansgaard-Oeschger cycles in the Greenland ice cores, including similar subdivision of the cycles into warmer interstadial and colder stadial sections. The remarkably close agreement between the benthic faunas and their δ 18 O data and the record of the ice cores provides new empirical evidence for a close relationship between the deep-ocean circulation and the abrupt climatic changes of the last glacial period.