Northern Svalbard Margin Research Articles

Arctic Marine Geology and Geophysics cruise to the northern Svalbard Margin and the Yermak Plateau

From the evening of July 23rd to the morning of August 1st, the Department of Geosciences at UiT The Arctic University of Norway, arranged an educational cruise to the northern Svalbard Margin/Yermak Plateau (Figure 1) for the courses GEO-3144 and GEO-8144 (Marine geology and geophysics cruise). The main aim of the cruise was to introduce the students to work at sea, which included acquisition of marine geological data (acoustic data and sediment cores) and lab analyses of split gravity cores. The students worked 12-hour shifts during the cruise The cruise may be known as: IG19-3_AMGG

CAGE15-1 Cruise Report : CAGE-CO2 Winter Cruise to the western and northwestern Svalbard margin and the Barents Sea

From the afternoon of April 1st to the morning of April 9th 2015, CAGE at the Department of Geology Uit, the Arctic University of Norway, arranged a scientific cruise aimed at investigating the western Barents Sea slope, western and northern Svalbard margin, methane seep sites at Vestnesa and Storfjorden Trough and the Barents Sea on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): Malangen Trough, Bjørnøya Trough Mouth Fan south and mid, Storfjorden Fan, Vestnesa Ridge, the northwest Svalbard slope to north of Schmeerenburgfjorden. On the track towards Tromsø we sampled in Storfjorden Trough. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE -Centre for Arctic Gas hydrate, Environment and Climate”, in which the sub-projects “Paleo-CIRCUS”, “OA-Ocean Acidification” is included.
 A total of 2 gravity cores, 8 plankton net casts and 22 CTD (conductivity-temperature-depth) casts were performed along the route to Northern Svalbard at the western Barents Sea slope. Data were also collected in Storfjorden Trough and the mouth of Storfjorden. In addition, CTD’s and a small chirp and multibeam survey was performed off Schmeerenburgfjorden, north of fjorden and in its northernmost part.
 Chirp profiles and multibeam lines were acquired during transits and during the survey of outer Schmeerenburgfjorden. The recording started from c. 71 N on the western Barents Sea slope and ended at 70.00 N.
 The cruise may be known as: CAGE15_1_CO2

CAGE15-6 Cruise Report: Arctic gas hydrate studies

RV Helmer Hanssen is the only vessel operating so far north (81 N) in October. One of the research questions addressed during this cruise is: Where do gas hydrate exist in the seabed and how much methane does it actually release? The CAGE 15-6 cruise explored potential gas hydrate charged sub-seabed environments and gas release zones at Storfjordrenna, Vestnesa and Svyatogor Ridge, Yermak Plateau, Sofia Basin and west of Prins Karls Foreland. Our route was traceable by www.sailwx.com. The weather forecasts from www.windyty.comwere used to prepare and adjust our cruise activities. In these Barents Sea-Arctic areas we carried out seismic profiling (mini GI 15/45 in 3 and large GI45/105 in 3) and 6 m long gravity coring for detecting gas hydrate, acoustic profiling (18, 38 and 120 kHz) for detecting gas flares in the water column, and CTD water sampling for gas analyses. Multibeam bathymetry mapping (EM300) data was collected on route for the entire cruise. We also ran echo sounder profiles along the NW Svalbard margin, across Yermak Plateau from west to east into the Sofia Basin and upslope towards the northern Svalbard margin. We reached the upper gas hydrate stability (GHSZ) theoretical outcrop zone but no acoustic evidence for extended gas release activity was found along the GHSZ outcrop zone at Yermak Plateau. The cruise may be known as: CAGE15_6

CAGE15-7 Cruise Report: GEO8144/3144 – Marine Geology and Geophysics Cruise, Greenhouse Gases in the Ocean

From the late afternoon of July 23rd to the morning of August 3rd, 2015, the Department of Geology Uit, the Arctic University of Norway, arranged a AMGG-Research School scientific teaching cruise aimed atinvestigating the western and northern Svalbard margin and the Barents Sea, the Fram Strait to east Greenland, methane seep sites at Vestnesa, Prins Karls Forland and Storfjorden Trough and on R/V “Helmer Hanssen”. Investigated areas were (in order of visiting sites on the cruise): west of Prins Karls Forland, Vestnesa Ridge, Molloy Deep, Fram Strait, East Greenland margin, Smeerenburgfjorden, Hinlopen, Storfjorden, Storfjorden Trough, and Leirdjupet south of Spitsbergenbanken. The scientific sampling was done within the framework of several ongoing projects at the Department of Geology, University of Tromsø: “CAGE – Centre for Arctic Gashydrate, Environment and Climate”, in which the sub-projects “Paleo-CIRCUS”, “OA-Ocean Acidification” is included. The responsible for this year’s course in GEO8144/GEO3144 is Prof. T.L. Rasmussen. A total of 26 gravity cores, 5 piston cores, 12 plankton net casts and 27 CTD (conductivity-temperature-depth) casts were performed at the planned stations. A total of 86.3 km (46 nm) of airgun surveys were run. 108.97 m mud was obtained in total. Chirp profiles and multibeam lines were acquired during transits and during surveys in Storfjorden, Storfjorden Trough and Leirdjupet. In addition, CTD’s and a small chirp and multibeam survey was performed Storfjorden and in Leirdjupet and airgun lines were run in Storfjorden Trough. The recording of echo-sounding started from c. 78 °N on the shelf outside Isfjorden and ended at c. 72 °N, with pauses when passing through protected areas of Svalbard (Smeerenburgfjorden and Hinlopen and respecting the 12 nm zone in Storfjorden). The cruise may be known as: CAGE15_7_AMGG

A 190-ka biomarker record revealing interactions between sea ice, Atlantic Water inflow and ice sheet activity in eastern Fram Strait

The northeastern Fram Strait at the entrance to the Arctic Ocean represents a key observatory for sea ice reconstructions as it sensitively reacts to environmental changes. A combined biomarker approach (HBIs, sterols, alkenones) was carried out on Core PS93/006-1 from the western Svalbard margin to reconstruct sea ice conditions related to glacial–interglacial cycles of the last 190 ka. The continuous presence of sea ice demonstrates the strong influence of polar water masses in the eastern Fram Strait. Glacial intervals are characterised by extended sea ice conditions with perennial sea ice cover during early MIS 6, the Penultimate Glacial Maximum, the interstadial MIS 5d, MIS 4 and the Last Glacial Maximum. Less severe, yet highly variable, sea ice conditions with more frequent summer melt dominated the interglacial stages. The opposing sea ice conditions along the western and northern Svalbard margin highlight the different regional impact of various environmental forces in eastern Fram Strait. Thus, the major expansion of the Svalbard Barents Sea Ice Sheet favoured the formation of perennial sea ice west of Svalbard while it triggered the establishment of marginal ice cover on the Yermak Plateau.

Late Weichselian ice stream configuration and dynamics in Albertini Trough, northern Svalbard margin

Ice stream configuration and sedimentary processes in Albertini Trough, north of Nordaustlandet, were studied using multibeam bathymetry, seismic reflection and sub-bottom profiles together with sediment gravity cores. Progradational sediment packages in the outer Albertini Trough suggest that streaming ice reached the shelf edge multiple times during the last c. 2.6 Ma. S–N-oriented glacial lineations imply that the Last Glacial Maximum (LGM) ice flow reached Albertini Trough mouth, and likely sourced from Duvefjorden and Albertinibukta. The ice flows from these two areas were separated on the inner shelf until they merged north of Karl XII Island, suggesting a geologic control on the ice flows. The scarceness of landforms characteristic of grounded ice margin retreat in the outermost Albertini Trough suggests a locally floating ice tongue. The presence of iceberg ploughmarks on the outer shelf suggests that the ice margin mainly disintegrated through calving. Push moraines and De Geer moraines superimposed on terminal moraines and a grounding zone wedge with superimposed SSW–NNE-oriented glacial lineations indicate a stepwise retreat of the ice margin with at least three readvances during deglaciation. Grounding line stabilization in the outer Albertini Trough is partly attributed to southwards shallowing and narrowing trough geometry. However, a southwards change in the orientation of glacial lineations from S–N to SSW–NNE suggests that the ice flow from Duvefjorden became more dominant in Albertini Trough during deglaciation. Spacing between the De Geer moraines generally increases southwards in Albertini Trough, implying an increased retreat rate during deglaciation. Three acoustic units were distinguished in the chirp data and correlated with till, glacimarine and marine deposits, respectively. Two sediment cores west of Albertini Trough consist of subglacial diamicton at the base with a sharp transition to homogenous marine mud above. The diamicton–mud transition in the cores was 14C-dated to 15.3 and 14.0 ka, implying increased retreat rate of the ice sheet margin during deglaciation across the continental shelf. The increased retreat rate is attributed to rapid sea level rise. Well-preserved listric fault scarps in the Albertini Trough mouth indicate relatively recent formation. The locally downfaulted bedrock beneath the glacial–interglacial sediments at the trough mouth probably contributed to the formation of thick and unstable sediment succession, which resulted in the faulting.

Geomorphology of the huge Hinlopen–Yermak landslide on the northern Svalbard margin

Submarine landslide scars, including the huge Hinlopen–Yermak slide-scar north of Svalbard (Fig. 1) (Vanneste et al. 2006; Winkelmann et al. 2006), are relatively common geomorphological features on glaciated continental margins. However, landslide characteristics, for example scar area, run-out and displaced volume, vary significantly (Hogan et al. 2013). A key pre-condition for failure is rapid deposition of mainly diamictic glacier-derived sediment on the slope during full-glacials, alternating with fine-grained interglacial deposition. This layered architecture, and the varying geotechnical properties of the debris, facilitate downslope mass-movements with a variety of possible triggers. Fig. 1. Marine geophysical data over Hinlopen–Yermak landslide scar, northern Svalbard. ( a ) Multibeam image showing slide scar. PR, arcuate pressure ridges. DR, detached sediment ridges. Acquisition systems Kongsberg EM300. Frequency 30 kHz (RV Jan Mayen ). Hydrosweep DS2. Frequency 15.5 kHz (RV Polarstern ). Kongsberg EM120. Frequency 12 kHz (RSS James Clark Ross ). Grid-cell size 100 m. ( b ) Seismic-reflection profile of slide headwall and post-slide sediment fill. Acquisition system two 40 cubic inch airguns. VE×6. ( c ) Bathymetric image of the complex eastern headwall area showing detached sediment ridges (DR and inset; VE×7) and blocky debris (BD) on slip planes. ( d ) Bathymetric image of rafted mega-blocks within slide debris. Ridges of material pushed up …

Huge iceberg ploughmarks and associated corrugation ridges on the northern Svalbard shelf

Linear to curvilinear depressions on high-latitude continental shelves have long been regarded as the signature of the ploughing action of iceberg keels impinging on the sedimentary seafloor (e.g. Woodworth-Lynas et al. 1991). These depressions vary in dimensions and pattern with the size of calved icebergs and their drift tracks through the polar seas. Two different sizes of iceberg have affected the shelf north of Svalbard, producing distinctive sets of ploughmarks (Dowdeswell et al. 2010). Large numbers of linear and curvilinear depressions are present on the seafloor of the northern Svalbard margin at water depths of <615 m (Fig. 1). The depressions are of two types. The first are large quasi-linear features up to 23 km long, 1 km wide and 80 m deep (Fig. 1a, d). These features are clustered within a fairly well-defined band of water depths (from 400 to 615 m over an area of c. 800 km2), above and below which few are present. At first sight many features appear linear; detailed inspection shows that some are slightly curvilinear, whereas others are composed of several straight sections interspersed with directional shifts of sometimes just a few degrees. In addition, individual linear features often appear to …

Glaciomarine sedimentation and bottom current activity on the north-western and northern continental margins of Svalbard during the late Quaternary

Palaeo-bottom current strength of the West Spitsbergen Current (WSC) and the influence of the Svalbard-Barents Sea Ice Sheet (SBIS) on the depositional environment along the northern Svalbard margins are poorly known. Two gravity cores from the southern Yermak Plateau and the upper slope north of Nordaustlandet, covering marine isotope stage (MIS) 1 to MIS 5, are investigated. Five lithofacies, based on grain size distribution, silt/clay ratio, content and mean of sortable silt (SS), are distinguished to characterise the contourite-dominated sedimentary environments. In addition, depositional environments are described using total organic carbon (TOC), total sulphur (TS) and calcium carbonate (CaCO3) contents of sediments. Facies A, containing coarse SS, suggests strong bottom current activity and good bottom water ventilation conditions as inferred from low TOC content. This facies was deposited during the glacial periods MIS 4, MIS 2 and during the late Holocene. Facies B is dominated by fine SS indicating weak bottom current and poor ventilation (cf. high TOC content of 1.2–1.6%), and correlates with the MIS 4/3 and MIS 2/1 transition periods. With an equal amount of clay and sand, fine SS and high content of TOC, facies C indicates reduced bottom current strength for intervals with sediment supply from proximal sources such as icebergs, sea ice or meltwater discharge. This facies was deposited during the last glacial maximum. Facies D represents mass-flow deposits on the northern Svalbard margin attributed to the SBIS advance at or near the shelf edge. Facies E sediments indicating moderate bottom current strength were deposited during MIS 5 and MIS 3, and during parts of MIS 2. This first late Quaternary proxy record of the WSC flow and sedimentation history from the northern Svalbard margin suggests that the oceanographic conditions and ice sheet processes have exerted first-order control on sediment properties.

Palaeoceanography of the Barents Sea continental margin, north of Nordaustlandet, Svalbard, during the last 74 ka

We investigated gravity core HH11‐09GC from 488 m water depth at the northern Svalbard margin in order to reconstruct changes in Atlantic Water (AW) inflow to the Arctic Ocean. The study was based on the distribution patterns of benthic and planktic foraminifera, benthic and planktic oxygen and carbon isotopes, lithology and physical properties of the sediments. The core contains sediments from Marine Isotope Stages (MISs) 5a to 1. MIS 4 was characterized by glacial conditions and at c. 65 ka the Svalbard‐Barents Sea Ice Sheet (SBIS) advanced. Polynya was formed in front of the SBIS at c. 62 ka. During late MIS 3 (32–29 ka) and MIS 2 (22–20 ka), a strong influence of AW resulted in high productivity of both planktic and benthic foraminiferal faunas. During 23–22 ka, the SBIS advanced to the shelf edge. The last deglaciation began at 18.5 ka and at 16.9 ka ‘a peak’ influx of meltwater from the retreating SBIS caused a weakening of the ocean circulation. At the start of the Bølling‐Allerød interstadial at c. 15.5 ka, inflow of relatively warm AW probably intensified the release of meltwater at 14 and 12.8 ka. This probably led to expansion of sea ice cover during the Younger Dryas stadial. The late Holocene from 3.7 ka was characterized by the presence of seasonal to perennial sea ice cover and a slight warming of the bottom waters. The sea ice cover decreased for a short period at 1.5 ka owing to the advection of relatively warm AW. Correlation with results from the northwestern Svalbard margin shows that the patterns of ice retreat and advance correlate closely with changes in inflow of AW and were regulated by meltwater discharge, sea ice export and insolation.

Late Quaternary ice flow and sediment delivery through Hinlopen Trough, Northern Svalbard margin: Submarine landforms and depositional fan

The morphology and distribution of submarine landforms in Hinlopen Trough, Northern Svalbard margin, and the upper continental slope beyond, are investigated using swath-bathymetric data, together with side-scan sonar, acoustic profiler records and sediment cores. Sun-illuminated images reveal a number of landform assemblages on the sea floor of Hinlopen Trough and confirm that this depression was occupied by an ice stream during the Late Weichselian glaciation around 20 ka before present. The geomorphology of the inner-shelf is characterised by bedrock drumlins and ice-sculpted bedrock. There is a middle-shelf transition from a rock bed to an unconsolidated sedimentary bed that contains highly-attenuated drumlins and megaflutes formed within a dark grey, matrix-supported diamict, interpreted as subglacial till. Outer-shelf landforms are mainly iceberg ploughmarks. The geomorphological imprint identified from Hinlopen Trough is similar to that of many former ice streams; the trough is dominated by elongate landforms orientated parallel to the inferred flow direction and is lacking in transverse features indicative of inter-ice stream locations. A characteristic down-flow progression in landform elongation is also observed, suggesting an increase in ice velocity across the continental shelf. The lack of grounding-zone features imaged from swath-bathymetric data implies that deglaciation was probably rapid within the trough. A large depositional fan exists on the upper continental slope beyond the trough, characterised by debris flow deposits relating to the down-slope transport of glacigenic sediment. Order of magnitude calculations of the volume of glacigenic sediment on the continental slope indicate that the ice stream provided high rates of debris delivery of around 5–7.5 m/ka. This suggests that Hinlopen Trough ice stream represented a major route for the transfer of ice and debris to the Hinlopen Fan on the northern continental margin of Svalbard during the Late Weichselian glaciation.

High-resolution geophysical observations of the Yermak Plateau and northern Svalbard margin: implications for ice-sheet grounding and deep-keeled icebergs

High-resolution geophysical evidence on the seafloor morphology and acoustic stratigraphy of the Yermak Plateau and northern Svalbard margin between 79°20′ and 81°30′N and 5° and 22°E is presented. Geophysical datasets are derived from swath bathymetry and sub-bottom acoustic profiling and are combined with existing cores to derive chronological control. Seafloor landforms, in the form of ice-produced lineations, iceberg ploughmarks of various dimensions (including features over 80 m deep and down to about 1000 m), and a moat indicating strong currents are found. The shallow stratigraphy of the Yermak Plateau shows three acoustic units: the first with well-developed stratification produced by hemipelagic sedimentation, often draped over a strong and undulating internal reflector; a second with an undulating upper surface and little acoustic penetration, indicative of the action of ice; a third unit of an acoustically transparent facies, resulting from debris flows. Core chronology suggests a MIS 6 age for the undulating seafloor above about 580 m. There are several possible explanations, including: (a) the flow of a major grounded ice sheet across the plateau crest from Svalbard (least likely given the consolidation state of the underlying sediments); (b) the more transient encroachment of relatively thin ice from Svalbard; or (c) the drift across the plateau of an ice-shelf remnant or megaberg from the Arctic Basin. The latter is our favoured explanation given the evidence currently at our disposal.

The 2005 HOTRAX Expedition to the Arctic Ocean

The Healy–Oden Trans-Arctic Expedition (HOTRAX'05) recovered 29 long piston cores and associated multicores along a transect from the Alaskan margin across the central Arctic Ocean to the northern Svalbard margin. The initial results focus on the age and stratigraphy of these cores using a variety of approaches including radiocarbon, paleomagnetic and other chronostratigraphic methods as well as detailed correlations of proxy records. High sedimentation cores from probable drift deposits are described from the shelf and continental slope north of Alaska. Provenance and sedimentary processes in these deposits include both currents and sea-ice rafting. Much lower sedimentation rates in the central Arctic Ocean show geographic variability consistent with the patterns of expected sediment distribution by ice and, to a smaller extent, subsurface currents. Insights into the Upper Quaternary stratigraphy and depositional history are provided in two papers on a core from the Mendeleev Ridge with sedimentation rates relatively elevated for this region. To compliment the results from the HOTRAX cores, two papers are included dealing with the stratigraphy and sedimentary processes on the Chukchi shelf and a modeling study addressing why the Marine Isotopic Stage 6 (ca. 140 ka) glaciation was substantially more extensive in the Arctic than the Last Glacial Maximum.

Dynamics of the Late Weichselian ice sheet on Svalbard inferred from high‐resolution sea‐floor morphology

High‐resolution bathymetric mapping of the fjords and continental shelf around the Svalbard archipelago shows an extensive pattern of large‐ and medium‐scale submarine landforms formed by differences in ice‐flow regimes. Mega‐scale glacial lineations, lateral moraines, transverse ridges and glaciotectonic features are superimposed on the large‐scale fjord, shelf and cross‐shelf trough morphology of the margin. From these landforms we have inferred the flow and dynamics of the last ice sheet on Svalbard. Major fjords and their adjacent cross‐shelf troughs have been identified as the main routes for ice streams draining the ice sheet. On the west coast of Svalbard major pathways existed along Bellsund, Isfjorden and Kongsfjorden. Along the northern Svalbard margin most of the ice drained through the Woodfjorden cross‐shelf trough and Wijdefjorden‐Hinlopen strait. Extensive areas with trough‐parallel glacial lineations in the cross‐shelf troughs suggest fast ice flow by palaeo‐ice streams. Lateral ice‐stream moraines, several tens of kilometres in length, have been mapped along the margins of some of the cross‐shelf troughs, identifying the border zone between fast ice flow and stagnant or slow‐flowing ice on intervening banks. Several general implications can be drawn from the interpretation of the glacier‐derived submarine landforms around Svalbard. Firstly, the Late Weichselian ice sheet was partitioned into fast‐flowing ice streams separated by slower moving ice. Secondly, our submarine morphological evidence supports earlier sedimentological, stratigraphical and chronological studies in implying that a large ice sheet reached the shelf edge around almost all of western and northern Svalbard in the Late Weichselian. The idea of a relatively restricted ice sheet over Svalbard, with ice‐free conditions in some areas of the west coast at the Last Glacial Maximum, is therefore unlikely to be correct. Thirdly, the ice sheet appears to have retreated more rapidly from the cross‐shelf troughs and outer fjords, although sometimes this occurred in a punctuated pattern indicated by grounding‐zone wedges, and more slowly from the intervening shallower banks. In addition, a grounding zone for the ice sheet has been mapped at the shelf edge 10–20 km off the northwest coast of Svalbard, suggesting that ice did not reach the adjacent Yermak Plateau during the Late Weichselian.

The Hinlopen Slide: A giant, submarine slope failure on the northern Svalbard margin, Arctic Ocean

New swath bathymetry data unveil a giant, submarine landslide located at the mouth of the Hinlopen transverse trough on the northern Svalbard margin, Arctic Ocean. Despite the relatively small drainage and slide scar areas, the Hinlopen Slide is exceptional in volume, headwall height and dimensions of the rafted blocks. From the c. 2200 km 2 large headwall area, approximately 1350 km 3 of Plio-Pleistocene sediments have been evacuated from the continental margin to the Nansen Basin. The escarpment heights are unprecedented, exceeding 1400 m, whereas the rafted blocks observed in the intermediate part of the slide area are up to 450 m high and more than 5 km wide. These characteristics make the Hinlopen Slide one of the largest landslides worldwide, and the first mapped mega-slide in the Arctic Ocean. Within the amphitheatre-shaped slide scar area, a composite set of escarpments and multiple, roughly planar slip surfaces occur, as well as detached sediment ridges adjacent to the outer escarpment, arcuate pressure ridges in debris lobes and isolated slump debris or blocks. From this complex slide scar geomorphology, we infer that the Hinlopen Slide was a translational, multi-phase slope failure that developed retrogressively. The slide has not been dated yet; however, the geophysical data suggest a relatively young age, though probably pre-Holocene, inferred from the pattern of sediment infill within the slide scar area derived from the Hinlopen cross-shelf trough. A submarine landslide with these dimensions could have created a devastating tsunami, although its potential depends on sea ice conditions as well as the time lags of the multi-phase, retrogressive movement. Climate changes and the response of ice sheets, ocean-current systems, sediment delivery and seismicity related to glacio-isostatic deformation appear as critical factors controlling stability on glaciated margins.

Changes in the flow of Atlantic water into the Arctic Ocean since the last deglaciation: Evidence from the northern Svalbard continental margin, 80°N

The Svalbard archipelago is located in the high Arctic (76°–80°N) within the northernmost reach of the West Spitsbergen Current, which is the continuation of the North Atlantic Current. In this specific setting close to the Polar Front, even small variations in the current system are expected to give large and distinct signals in paleoceanographic parameters. Thus the Svalbard area is ideal for monitoring the past history of the inflow of Atlantic water to the Arctic Ocean. We have studied sediment core NP94‐51 taken outside the mouth of the Hinlopen Strait on the northern Svalbard shelf. The paleoceanographic development of the last deglaciation and the Holocene has been reconstructed using benthic and planktonic foraminifera, oxygen isotopes, and ice‐rafted detritus. The results show that the first strong subsurface inflow of Atlantic water to the Arctic Ocean after the Last Glacial Maximum commenced at 12.6 14C kyr B.P. (circa 15,000 calendar (cal) years B.P.) during the Bølling‐Allerød interstadial. During the Younger Dryas, polar conditions prevailed at the surface with extensive sea ice cover, and the inflow of Atlantic‐derived water was generally diminished. The inflow of more saline, but still cold Atlantic water was relatively strong during the early Holocene and caused intensified seasonal biological productivity. The Atlantic water inflow declined gradually during the mid‐Holocene. Between 4500 and 1100 cal years B.P. the inflow was very weak, and the bottom waters over the northern Svalbard margin were cold and of lower salinity. During the last ∼1000 years, climatic conditions improved such that the subsurface inflow of Atlantic‐derived water increased. However, the surface waters were still cold.

Late glacial palaeoceanography of Hinlopen Strait, northern Svalbard

Timing and structure of the Late and post-glacial development of the northern Svalbard margin, together with the initial influx of Atlantic water into the Arctic Ocean are still very poorly constrained. We investigated a sediment core (NP94-51) from a high accumulation area on the continental shelf north of Hinlopen Strait with the purpose of resolving the timing and structure of the last deglaciation. Detailed analyses of ice-rafted detritus, benthic and planktonic foraminiferal fauna, diatom flora, grain size and radiocarbon dates are used to reconstruct the palaeoceanographic evolution of the area. Our results indicate that the disintegration of Hinlopen Strait ice and possibly the northern margin of the Svalbard Ice Sheet commenced between 13.7 and 13.9 14C Ky BP. Influx of subsurface Atlantic waters into the area (12.6 14C Ky BP) and the retreat of the sea ice cover, with the accompanying opening of the surface waters (10.8 14C Ky BP), happened at different times and both much later than the disintegration of the ice sheets. The transition into the Holocene shows a two-step warming.