Oceanic and atmospheric variations during the last deglaciation in the Fram Strait (Arctic Ocean): a coupled high-resolution organic-geochemical and sedimentological study

Birgel, Daniel; Hass, H Christian

doi:10.1016/j.quascirev.2003.10.001

Cited by 51 publications

(46 citation statements)

References 104 publications

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“…As shown, our biomarker-based observations and interpretations align strongly with previous palaeoclimate records for the northern Fram Strait 9,12,19,23 , but they also provide more specific palaeoceanographic information. First, during intervals of the Late Weichselian, our biomarker record indicates extended periods of near-perennial sea-ice cover (29-27.5 kyr bp and 23.5-17 kyr bp; Fig.…”

supporting

confidence: 87%

“…These observations, together with an absence of benthic foraminifera in PS2837-5 (ref. 23), are associated with a deterioration of thermohaline processes and reduced bottom-current activity in Fram Strait 9 , and demonstrate that this permanent sea-ice cover affected both primary production and higher trophic levels, resulting in a widespread ecological decline. In previous studies carried out on PS2837-5, this abrupt cooling event was tentatively assigned as the Intra-Allerød Cold Period (IACP; refs 9, 23).…”

mentioning

confidence: 95%

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Variability of sea-ice conditions in the Fram Strait over the past 30,000 years

Müller

Massé²,

Stein³

et al. 2009

Nature Geosci

188

181

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Sea ice is a critical component of the climate system: variations in sea-ice cover affect the albedo of polar regions, and also the rate of deepwater formation 1,2 . Changes in the sea-ice cover of the North Atlantic Ocean are thought to have been related to abrupt climate changes throughout the last glacial termination 3 , but reconstructions of sea-ice conditions are rare. Here we use the sedimentary abundance of the IP 25 and brassicasterol biomarkers, produced by sea-ice-associated diatoms and open-water phytoplankton, respectively, to generate a record of sea-ice conditions in the northernmost Atlantic Ocean for the past 30,000 years. Our reconstruction shows that a stationary margin between sea-ice cover and the open ocean existed during the Last Glacial, although perennial sea-ice cover prevailed for most of the Last Glacial Maximum. An early warming about 14,000 years ago was associated with ice-free conditions; however, seasonal sea ice was present throughout the Holocene. We find temporal links between our record of sea ice and reconstructions of the amount of relatively warm Atlantic water advected into the Nordic Seas 4,5 . We therefore conclude that changes in sea-ice conditions are linked to regional and global climate anomalies and oceanographic circulation in the North Atlantic.The distribution of sea ice in Fram Strait, the only deepwater connection (∼2,600 m mean water depth) between the Arctic and Atlantic oceans, is mainly controlled by the inflow of temperate water from the North Atlantic along the western continental margin of Spitsbergen through the Norwegian and West Spitsbergen currents 1 . In contrast, the East Greenland current carries cold water (and sea ice) southward through this gateway 1 (Fig. 1). The relative contributions of these currents strongly influence the thermohaline circulation, thus contributing to global climate 1 .Previously, it has been shown that, when detected in marine sediments, a C 25 isoprenoid lipid (IP 25 ) biosynthesized by Arctic sea-ice diatoms acts as a proxy for previous spring sea-ice occurrence and subsequent melt 6,7 , whereas the phytoplanktonderived sterol brassicasterol, reflects open-ocean conditions during summer 8 . In the current study, we present organic carbon 9 (global productivity and terrigenous organic carbon input) and fluxes of IP 25 (sea ice) and brassicasterol (phytoplankton; ref. 9) for a sediment core (PS2837-5) from the western flank of the Yermak Plateau (81 • 13.99 N, 02 • 22.85 E, northwest of Spitsbergen, 1,042 m water depth; ref. 10) close to the present-day summer sea-ice margin in Fram Strait (Fig. 1). We use the previously reported age model of PS2837-5, which is based on 14 accelerator mass spectrometry 14 C ages of tests of the planktic foraminifer Neogloboquadrina pachyderma sin. and assumes a marine-reservoir correction of 400 years and linear interpolation between 14 C-dated horizons 11 . In the following, ages are given in calibrated calendar years before present. For much of the interval between 30 and 17 kyr bp (La...

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supporting

confidence: 87%

mentioning

confidence: 95%

Variability of sea-ice conditions in the Fram Strait over the past 30,000 years

Müller

Massé²,

Stein³

et al. 2009

Nature Geosci

188

181

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“…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.…”

Section: Discussionmentioning

confidence: 69%

“…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.…”

Section: Resultsmentioning

confidence: 99%

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

Rasmussen

Thomsen

2013

Nat Commun

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The climate of the last glaciation was interrupted by numerous abrupt temperature fluctuations, referred to as Greenland interstadials and stadials. During warm interstadials the meridional overturning circulation was active transferring heat to the north, whereas during cold stadials the Nordic Seas were ice-covered and the overturning circulation was disrupted. Meltwater discharge, from ice sheets surrounding the Nordic Seas, is implicated as a cause of this ocean instability, yet very little is known regarding this proposed discharge during warmings. Here we show that, during warmings, pink clay from Devonian Red Beds is transported in suspension by meltwater from the surrounding ice sheet and replaces the greenish silt that is normally deposited on the north-western slope of Svalbard during interstadials. The magnitude of the outpourings is comparable to the size of the outbursts during the deglaciation. Decreasing concentrations of ice-rafted debris during the interstadials signify that the ice sheet retreats as the meltwater production increases.

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“…Following Zamelczyk et al (2014), we correlated the magnetic susceptibility values of core MSM5/5-712-2 with the Western Svalbard slope MS stack by Jessen et al (2010) and the susceptibility values of core PS2837-5 from the Yermak Plateau (Niessen et al, 1997; see S1). Further, by means of correlating the TOC contents of core MSM5/5-712-2 and core PS2837-5 from the Yermak Plateau (S1; Birgel and Hass, 2004) we identified several tie points and selected three AMS 14 C ages of core PS2837-5 (Nørgaard-Pedersen et al, 2003 Table S2) that we adopted to improve the herein presented age model of core MSM5/5-712-2 (Fig. 2).…”

Section: Core Chronologymentioning

confidence: 99%