Palaeoceanographic evolution of the SW Svalbard shelf over the last 14 000 years

Abstract

The palaeoceanographic evolution of the SW Svalbard shelf west of Hornsund over the last 14 000 years was reconstructed using benthic foraminiferal assemblages, stable oxygen and carbon isotopes, and grain‐size and ice‐rafted debris data. The results reveal the complexity of the feedbacks influencing the shelf environment: the inflow of Atlantic and Arctic waters (AW and ArW, respectively), and the influence of sea ice and tidewater glaciers. The inflow of subsurface AW onto the shelf gradually increased with the first major intrusion at the end of the Bølling‐Allerød. During the Younger Dryas, the shelf was affected by fresh water originating from sea ice and glacier discharge. Glaciomarine conditions prevailed until the earliest Holocene with the intense deliveries of icebergs and meltwater from retreating glaciers and the occasional penetration of AW onto the shelf. Other major intrusions of AW occurred before and after the Preboreal oscillation (early Holocene), which resulted in more dynamic and open‐water conditions. Between 10.5 and 9.7 cal. ka BP, the shelf environment transformed from glaciomarine to open marine conditions. Between c. 9.7 and 6.1 cal. ka BP the AW advection reached its maximum, resulting in a highly dynamic and productive environment. At c. 6.1 cal. ka BP, the inflow of AW onto the Svalbard shelf decreased due to the intensification of the Greenland Gyre and the subduction of AW under the sea‐ice‐bearing ArW. Bioproductivity decreased over the next c. 5500 years. During the Little Ice Age, bioproductivity increased due to favourable conditions in the marginal sea‐ice zone despite the effects of cooling. The renewed advection of AW after AD 1850 started the climate warming trend observed presently. Our findings show that δ18O can be used to reconstruct the dominances of different water‐masses and, with some caution, as a proxy for the presence of sea ice in frontal areas over the northwestern Eurasian shelves.

Holocene ice-free strait followed by dynamic Neoglacial fluctuations: Hornsund, Svalbard

“…BP (Figure 5) may not result from the glacier advances and the blockage of the strait. The IRD values from Storfjorden and the Svalbard shelf west of Hornsund remained low in these periods (Nielsen and Rasmussen, 2018; Telesiński et al, 2018) and lake records have not revealed glacier advances in other regions of Svalbard (Allaart et al, 2021; de Wet et al, 2018; Røthe et al, 2015, 2018; Svendsen and Mangerud, 1997). In Hornsund, the radiocarbon dates of peat melted on the surface of Hansbreen suggest significant reduction in the glacier area around 7.9 and 5.9 ka cal.…”

Multiproxy paleoceanographic study from the western Barents Sea reveals dramatic Younger Dryas onset followed by oscillatory warming trend

“…4). The YD is reflected in multiple records from the northeastern North Atlantic Ocean 7,8,19 . For instance, in Kveithola Trough located south of Storfjordrenna, the sea-ice proxy P III IP 25 (Fig.…”

“…Numerous marine sedimentary records attest that the northern hemisphere was subjected to rapid cooling over circa 1000 years during the YD 7,8 . As earlier investigations focused mainly on overviews of Late Glacial and Holocene paleoceanography of the Nordic Seas, the YD interval in marine records was presented in low temporal resolution (several hundreds of years).…”

The significance of Atlantic Water routing in the Nordic Seas: The Holocene perspective

“…interpreted as a direct proxy of AW inflow, raised slowly and gradually (Figure 5). In comparison with the Greenland Sea record, in the northeastern Nordic Seas, the sSST (site M23258, Risebrobakken et al, 2011), as well as the abundance of AW indicators (site JM07-015, Telesiński et al, 2018), increased rapidly (Figure 5) indicating a maximum in AW advection already 10-11 ka BP (Husum and Hald, 2012;Risebrobakken et al, 2011). Shallow water (<50 m) temperatures around Svalbard were higher than at present (Mangerud and Svendsen, 2017) and AW reached the northern Svalbard shelf (Ślubowska-Woldengen et al, 2007), the northern Barents Sea (Berben et al, 2017) and as far as the western Fram Strait.…”

“…Rasmussen and Thomsen, 2008, 2010) and the NAC flow along the Scandinavian, Barents Sea and Svalbard continental margins (e.g. Groot et al, 2014; Rasmussen et al, 2007, 2012, 2014; Ślubowska-Woldengen et al, 2007; Telesiński et al, 2018; Łącka et al, 2015, 2019) and/or through the Fram Strait into the Arctic Ocean (e.g. Aagaard-Sørensen et al, 2014; Spielhagen et al, 2011; Werner et al, 2015).…”