Radiocarbon dated common mussels Mytilus edulis from eastern Svalbard and the Holocene marine climatic optimum

The common mussel Mytilus edulis is an indicator of milder marine conditions in the Arctic, with stronger Atlantic Water influx, during the Holocene and earlier interglacials. Twelve Holocene radiocarbon dates of mytilus from eastern Svalbard fall between ca 8800 and 5000 BP and roughly delimit the marine climatic optimum period there. The beginning of this period in the east coincides with the immigration of boreal extralimital molluscs to western Svalbard, indicating the culmination of Holocene Atlantic influence.     

Eurasian ice-sheet interaction in northwestern Russia throughout the late Quaternary

Sediment successions from the Kanin Peninsula and Chyoshskaya Bay in northwestern Russia contain information on the marginal behaviour of all major ice sheets centred in Scandinavia, the Barents Sea and the Kara Sea during the Eemian-Weichselian. Extensive luminescence dating of regional lithostratigraphical units, supported by biostratigraphical evidence, identifies four major ice advances at 100-90, 70-65, 55-45 and 20-18 kyr ago interbedded with lacustrine, glaciolacustrine and marine sediments. The widespread occurrence of marine tidal sediments deposited c. 65-60 kyr ago allows a stratigraphical division of the Middle Weichselian Barents Sea and Kara Sea ice sheets into two shelf-based glaciations separated by almost complete deglaciation. The first ice dispersal centre was in the Barents Sea and thereafter in the Kara Sea. It is possible to extract both flow patterns from ice marginal landforms inside the southward termination. Accordingly, it is proposed that the Markhida line and its western continuation are asynchronous and originate from two separate glaciations before and after the marine transgression. The marine sedimentation occurred during a eustatic sea-level rise of up to 20 m/1000 yr, i.e. the Mezen Transgression. We speculate that the rapid eustatic sea-level rise triggered a collapse of the Barents Sea Ice Sheet at the MIS (Marine Isotope Stage) 4 to 3 transition. This is motivated by lack of an early marine highstand, the timing of events, and the marginal position of Arkhangelsk relative to open marine conditions.     

Impact of grazing from capelin (Mallotus villosus) on zooplankton: a case study in the northern Barents Sea in August 1985

The distribution of capelin was mapped in the area east of Hopen. Zooplankton was sampled with Juday net and 1 m² MOCNESS sampler, and analysed with respect to hydrography and capelin abundance. The capelin "front" coincided more or less with the physical Polar Front, and this complicated the interpretation of the results. Strong indications for a grazing impact by capelin on zooplankton were nevertheless obtained. The zooplankton biomass was significantly lower in the area with high abundance of capelin than in the area with no capelin. This effect was due to a lower biomass of relatively large zooplankton (> 1 mm size fraction) and seen most clearly in data obtained with the MOCNESS. The biomass of zooplankton in the upper 100 m was very low where capelin was present, suggesting rapid depletion of the major prey items. The biomass (m ⁻²) of capelin in the capelin front area was about three times higher than the biomass of zooplankton in areas without capelin. The capelin front would therefore have the potential to graze down the available prey in 3-4 days. Light seems to be an important factor for the predation impact by capelin, resulting in strong interactions between capelin predation and zooplankton vertical distribution.     

Glacial history of interior Jameson Land, East Greenland

The plateaus between 400 and 800 m a.s.l. around the water-divides on central and eastern Janieson Land are covered by the 'Jameson Land Drift' up to 50 m thick glacial. placiotluvial and glaciolacustrine deposits. A high content of far-travelled wcsterii rocks indicates the overriding by extensive glaciers channelled from the west through the Scoresby Sund basin. The Jameson Land Drift deposits have bccn lithostratigraphically divided into two groups. each representing the sedimentary successions from one glaciation in the wider sense of the word. sediments from the lower Lollandselv glaciation are upwards delimited by a distinct periglacial surface. TL-dates suggest a prc-Saalian (approximately isotope stages 11–9) age. The following Scoreshby Sund glaciation . when most of the studied Jameson Land Drift sediments were laid down. is of Saalian age (e. isotope stages 8 6). The deposits from the Scoresby Sund glaciation are interpreted as representing a complete glaciation deglaciation succession, including proglacial sandur and glaciolacustrine sediments. followed by till deposition, with an overlying succession of glaciolacustrinc and glaciofluvial sediments. From 200–250 m to c . 400 m a.s.l. there is a driftless area, exposing Jurassic sandstones, probably a result of intensive and long-lasting periglacial erosion. Extensive occurrences of tors and of glaciofluvially (subglacially as well as subaerially) eroded canyons and channels characterize the landscape. A similar. although less well defined. upper driftless zone is found above c 500 m a.s.l. on northern Jameson Land, north of the drift-covered plateaus. During the Wcichsclian (isotope stages 5d 2). thick glacial. fluvial and marine deposits were laid down in a coastal zone below c . 200 m a.s.l., and only cold-based local ice caps seem to have existed on the interior plateaus of Jameson Land. The now driftless areas were characterized by periglacial erosion during this period.     

Dynamics of the last glaciation in eastern Svalbard as inferred from glacier-movement indicators

Glacial striae and other ice movement indicators such as roche moutonées, glacial erratics, till fabric and glaciotectonic deformation have been used to reconstruct the Late Weichselian ice movements in the region of eastern Svalbard and the northern Barents Sea. The ice movement pattern may be divided into three main phases: (1) a maximum phase when ice flowed out of a centre east or southeast of Kong Karls Land. At this time the southern part of Spitsbergen was overrun by glacial ice from the Barents Sea; (2) the phase of deglaciation of the Barents Sea Ice Sheet, when an ice cap was centred between Kong Karls Land and Nordaustlandet. At the same time ice flowed southwards along Storfjorden; and (3) the last phase of the Late Weichselian glaciation in eastern Svalbard is represented by local ice caps on Spitsbergen, Nordaustlandet, Barentsoya and Edgeøya.
The reconstructed ice flow pattern during maximum glaciation is compatible with a centre of uplift in the northern Barents Sea as shown by isobase reconstructions and suggested by isostatic modelling.