Paleoceanography of the Barents Sea during the Holocene

Abstract

[1] We measured the oxygen isotopic composition of planktonic and benthic foraminifera in three cores collected at key positions to reconstruct the paleoceanography of the Barents Sea: core ASV 880 on the path of the northern branch of Atlantic water inflowing from the Arctic Ocean, core ASV 1200 in the central basin near the polar front, and core ASV 1157 in the main area of brine formation. Modern seawater d 18 O measurements show that far from the coast, d 18 O variations are linearly linked to the salinity changes associated with sea ice melting. The foraminifer d 18 O records are dated by 14 C measurements performed on mollusk shells, and they provide a detailed reconstruction of the paleoceanographic evolution of the Barents Sea during the Holocene. Four main steps were recognized: the terminal phase of the deglaciation with melting of the main glaciers, which were located on the surrounding continent and islands, the short thermal optimum from 7.8 ka B.P. to 6.8 ka B.P., a cold mid-Holocene phase with a large reduction of the inflow of Atlantic water, and the inception of the modern hydrological pattern by 4.7 ka B.P. Brine water formation was active during the whole Holocene. The paleoclimatic evolution of the Barents Sea was driven by both high-latitude summer insolation and the intensity of the Atlantic water inflow.

Late Weichselian and Holocene palaeoceanography of Storfjordrenna, southern Svalbard

“…13 000 cal yr BP). We suggest that the records located on the western and northern shelf of Svalbard directly mirror the effect of warmer Atlantic Water inflow, whereas records from Storfjordrenna were under the influence of isotopically lighter Arctic Water from the Barents Sea (Duplessy et al, 2005). The shift from the Arctic Water domain to the Atlantic Water domain during the end of the early Holocene is also visible on a scatter plot of δ 13 C against δ 18 O (Fig.…”

“…6 reflect temperature variations at the coring site according to the isotopically lighter ArW palaeotemperature model (Duplessy et al, 2005). Another explanation for the heavier δ 18 O periods during the YD could be the intermittent inflow of warmer AW; however, this is unlikely to cause the synchronous disappearance of IRD.…”

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

“…An increased inflow of Atlantic water in the early Holocene is also evident from several records from the Svalbard and Barents Sea region (e.g., Duplessy et al, 2005;Ślubowska-Woldengen et al, 2007;Chistyakova et al, 2010;Rasmussen et al, 2012;Klitgaard-Kristensen et al, 2013) Sea , transfer-function-generated bottom water temperatures , and benthic foraminiferal assemblages (Ślubowska et al, 2005;Skirbekk et al, 2010) at the western and northern Svalbard shelf. Timing of the onset of increased inflow of Atlantic water agrees well between the SW Barents Sea, Kveithola, and the western Svalbard margin with an onset around 11 500 yr BP (Fig.…”

The Early to Mid‐Holocene Thermal Optimum in the North Atlantic

“…Some of the sites providing evidence for a colder early to mid-Holocene are from upwelling regions; hence some of the cold anomalies may be related to enhanced wind-driven upwelling. There appears to be a poleward amplification of the thermal anomaly, as well as a clear tendency that the warmest temperature interval started earlier and lasted for a shorter period towards the Arctic than further south, where it often appeared as a warm phase between about 8 to 6 ka (Koç et al 1994;Sarnthein et al 2003;Duplessy et al 2005;Hald et al personal communication). Jansen et al ..…”