Late Weichselian and Holocene palaeoceanography of Storfjordrenna, southern Svalbard

Abstract

Abstract. Multiproxy analyses (including benthic and planktonic foraminifera, δ 18 O and δ 13 C records, grain-size distribution, ice-rafted debris, XRF geochemistry and magnetic susceptibility) were performed on a 14 C-dated marine sediment core from Storfjordrenna, located off of southern Svalbard. The sediments in the core cover the termination of Bølling-Allerød, the Younger Dryas and the Holocene and reflect general changes in the oceanography/climate of the European Arctic after the last glaciation. Grounded ice of the last Svalbard-Barents Sea Ice Sheet retreated from the coring site ca. 13 950 cal yr BP. During the transition from the subglacial to glaciomarine setting, Arctic Waters dominated the hydrography in Storfjordrenna. However, the waters were not uniformly cold and experienced several warmer spells. A progressive warming and marked change in the nature of the hydrology occurred during the early Holocene. Relatively warm and saline Atlantic Water began to dominate the hydrography starting from approximately 9600 cal yr BP. Although the climate in eastern Svalbard was milder at that time than at present (smaller glaciers), two periods of slight cooling were observed in 9000-8000 and 6000-5500 cal yr BP. A change in the Storfjordrenna oceanography occurred at the beginning of the late Holocene (i.e. 3600 cal yr BP) synchronously with glacier growth on land and enhanced bottom current velocities. Although cooling was observed in the Surface Water, Atlantic Water remained present in the deeper portion of the water column of Storfjordrenna.

Geophysical constraints on the dynamics and retreat of the Barents Sea ice sheet as a paleobenchmark for models of marine ice sheet deglaciation

“…Similarly, radiocarbon dates from ice‐proximal sediments within Franz Victoria Trough and Svyataya Anna Trough confirm that the deepest troughs along the northern Barents Sea were ice free by circa 16 cal ka B.P. (Figure ) [ Polyak and Solheim , ; Polyak et al ., ; Kleiber et al ., ; Łącka et al ., ].…”

Atlantic Water advection vs glacier dynamics in northern Spitsbergen since early deglaciation

“…During the Late Glacial Maximum (∼ 21-18 ka; Svendsen et al, 2004), Svalbard's glaciers and ice caps were part of the Svalbard-Barents Sea Ice Sheet. This grounded ice sheet covered the entire Barents Sea and expanded as far as the shelf break of Svalbard (Landvik et al, 1998). It must have been connected to the Fennoscandian Ice Sheet during the Last Glacial Maximum (Hughes et al, 2016;Landvik et al, 1998;Svendsen et al, 2004).…”

A new genus and two new species of Thyasiridae associated with methane seeps off Svalbard, Arctic Ocean

“…The Håkon Mosby mud volcano (HMMV) was discovered in 1989 at the southern border of the Barents Sea (72°N) and has been the focus of extensive biogeochemical and bio-logical studies (Gebruk et al 2003;Niemann et al 2006;Lösekann et al 2007;Decker & Olu 2012;Ryba-kova et al 2013). Seafloor emissions of methane at HMMV occur from gas hydrates in the sub seabed (Vogt et al 1997;Lein et al 1999) and support chemo-associated faunal populations. The macrofauna at HMMV caldera is represented by known chemosym-biotic organisms including siboglinid worms mixed with bivalves e.g.…”

“…During the Last Glacial Maximum (Late Weichselian interstadial period), the Barents Sea and Svalbard were covered by an extensive marine-based ice sheet, with average global sea level ∼126 m lower than today (Peltier & Fairbanks 2006;Patton et al 2015). Deglaciation of this Barents Sea Ice Sheet (BSIS) from the shelf break started around 20,000 years ago (Jessen et al 2010) and seawater began to penetrate outer troughs in the Barents Sea by 16,000 ka BP and later on also into the fjords of Svalbard (Jessen et al 2010;Łącka et al 2015). Palaeontological records from sediment cores sampled in Storfjordrenna show that communities of foraminifera followed the different water masses (Arctic, Atlantic, fresh or saline), entering Storfjordrenna throughout the degla-ciation of the BSIS (Rasmussen et al 2007;Rüther et al 2011;Łącka et al 2015).…”

“…Deglaciation of this Barents Sea Ice Sheet (BSIS) from the shelf break started around 20,000 years ago (Jessen et al 2010) and seawater began to penetrate outer troughs in the Barents Sea by 16,000 ka BP and later on also into the fjords of Svalbard (Jessen et al 2010;Łącka et al 2015). Palaeontological records from sediment cores sampled in Storfjordrenna show that communities of foraminifera followed the different water masses (Arctic, Atlantic, fresh or saline), entering Storfjordrenna throughout the degla-ciation of the BSIS (Rasmussen et al 2007;Rüther et al 2011;Łącka et al 2015). The physical conditions at the seabed close to a glacier front are an extreme environment for many benthic and sessile organisms (Włodarska- Kowalczuk & Pearson 2004;Włodarska-Kowalczuk et al 2005).…”