Paleoceanographic evolution of the SW Svalbard margin (76°N) since 20,000 ¹⁴C yr BP

Abstract

Two cores from the southwestern shelf and slope of Storfjorden, Svalbard, taken at 389 m and 1485 m water depth have been analyzed for benthic and planktic foraminifera, oxygen isotopes, and ice-rafted debris. The results show that over the last 20,000 yr, Atlantic water has been continuously present on the southwestern Svalbard shelf. However, from 15,000 to 10,000 14C yr BP, comprising the Heinrich event H1 interval, the Bølling–Allerød interstades and the Younger Dryas stade, it flowed as a subsurface water mass below a layer of polar surface water. In the benthic environment, the shift to interglacial conditions occurred at 10,000 14C yr BP. Due to the presence of a thin upper layer of polar water, surface conditions remained cold until ca. 9000 14C yr BP, when the warm Atlantic water finally appeared at the surface. Neither extensive sea ice cover nor large inputs of meltwater stopped the inflow of Atlantic water. Its warm core was merely submerged below the cold polar surface water.

Pink marine sediments reveal rapid ice melt and Arctic meltwater discharge during Dansgaard–Oeschger warmings

“…1). The outflows during MIS 3 can probably best be compared with the outflow during the Bølling interstadial at the beginning of the deglaciation c. 14.5 kyr BP, when a 10 cm to more than 2 m thick laminated bed was deposited along the western margin of Svalbard over a time span of less than 400 years 23,24,28,33 , which is comparable to the estimated duration of the melting events during MIS 3 (see above). The bed is found at distances from the ice margin that are comparable to the distance from our core site to the ice margin during MIS 3.…”

“…However, it is more likely that the differences are primarily caused by frequent changes in sedimentation rate. Several studies have shown that the sedimentation rate on the Svalbard margin was low during Heinrich event H1 and very high during the following Bølling interstadial 13,[22][23][24][25] . It seems probable that similar differences occurred between the stadials and interstadials studied here.…”

Timing of massive ‘Fleuve Manche’ discharges over the last 350kyr: insights into the European ice-sheet oscillations and the European drainage network from MIS 10 to 2

“…For the last glacial period, the huge 'Fleuve Manche' discharges dating from ca. 18 ka correlate with significant freshwater fluxes from the circum-North Atlantic ice sheets, as reported from the FIS (Kleiber et al, 2000;Dahlgren and Vorren, 2003;Lekens et al, 2005;Rasmussen et al, 2007), the BIIS (Zaragosi et al, 2001;Hall et al, 2006;Ménot et al, 2006;Toucanne et al, 2008) and the LIS (Clarke et al, 1999;Tripsanas and Piper, 2008), indicating that the 'Fleuve Manche' activity reflected a large-scale event of meltwater releases. Geochemical and isotopical data from numerous cores from the North Atlantic show a sharp concomitant decrease in the rate of deep-water formation leading to the HE 1 and a collapsed THC until ca.…”

Reconstruction of Atlantic water variability during the Holocene in the western Barents Sea

“…Several studies record a cooling in the late Holocene in both the bottom (Ślubowska-Woldengen et al, 2007;Risebrobakken et al, 2010) and surface water masses (Voronina et al, 2001;Hald et al, 2007;Rasmussen et al, 2007;Risebrobakken et al, 2010), which could be related to declining summer insolation (Berger and Loutre, 1991) or displacements of Arctic and polar water masses (Hald et al, 2007). Opposite to this cooling, two high-resolution studies from Bear Island and the western and northern Svalbard shelf (Jernas et al, 2013) infer a warming over the last ∼ 200 yr induced by the renewed inflow of Atlantic water.…”