Diachronous evolution of sea surface conditions in the Labrador Sea and Baffin Bay since the last deglaciation

Gibb, Olivia; Steinhauer, Sarah; Fréchette, Bianca; Vernal, Anne de; Hillaire‐Marcel, Claude

doi:10.1177/0959683615591352

Cited by 56 publications

(113 citation statements)

References 92 publications

(158 reference statements)

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“…The hypothesis that dense sea ice persisted in Baffin Bay into the Early Holocene (Gibb et al . ) is not supported by our results, or those of Knudsen et al . ().…”

Section: Discussioncontrasting

confidence: 98%

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Furze

Pieńkowski

McNeely

et al. 2017

Boreas

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Core 2011804-0010 from easternmost Lancaster Sound provides important insights into deglacial timing and style at the marine margin of the NE Laurentide Ice Sheet (LIS). Spanning 13.2-11.0 cal. ka BP and investigated for ice-rafted debris (IRD), foraminifera, biogenic silica and total organic carbon, the stratigraphy comprises a lithofacies progression from proximal grounding line and sub-ice shelf environments to open glaciomarine deposition; a sequence similar to deposits from Antarctic ice shelves. These results are the first marine evidence of a former ice shelf in the eastern Northwest Passage and are consistent with a preceding phase of ice streaming in eastern Lancaster Sound. Initial glacial float-off and retreat occurred >13.2 cal. ka BP, followed by formation of an extensive deglacial ice shelf during the Younger Dryas, which acted to stabilize the retreating margin of the NE LIS until 12.5 cal. ka BP. IRD analyses of sub-ice shelf facies indicate initial high input from source areas on northern Baffin Island delivered to Lancaster Sound by a tributary ice stream in Admiralty Inlet. After ice shelf break-up, Bylot Island became the dominant source area. Foraminifera are dominated by characteristic ice-proximal glaciomarine benthics (Cassidulina reniforme, Elphidium excavatum f. clavata), complemented by advected Atlantic water (Cassidulina neoteretis, Neogloboquadrina pachyderma) and enhanced current indicators (Lobatula lobatula). The biostratigraphy further supports the ice shelf model, with advection of sparse faunas beneath the ice shelf, followed by increased productivity underopen water glaciomarine conditions. The absence of Holocene sediments in the core suggests that the uppermost deposits were removed, most likely due to mass transport resulting from the site's proximity to modern tidewater glacier margins. Collectively, this study presents important new constraints on the deglacial behaviour of the NE Laurentide Ice Sheet, with implications for past ice sheet stability, ice-rafted sediment delivery, and iceÀocean interactions in this complex archipelago setting.

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“…The hypothesis that dense sea ice persisted in Baffin Bay into the Early Holocene (Gibb et al . ) is not supported by our results, or those of Knudsen et al . ().…”

Section: Discussioncontrasting

confidence: 98%

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Furze

Pieńkowski

McNeely

et al. 2017

Boreas

View full text Add to dashboard Cite

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“…However, after 3350 cal a bp , core 204 is marked by a major change in the dinocyst assemblages with a dominance shift from O. centrocarpum to cysts of P. dalei (Fig. ), suggesting changes in surface water conditions during this period, which were not observed in other regional dinocyst records (e.g., Ouellet‐Bernier et al ., ; Gibb et al ., ). In the Arctic, cysts of P. dalei are associated with relatively warm, stratified and highly productive waters, and generally require SST higher than 4°C (Rochon et al ., ; Matthiessen et al ., ; Ribeiro et al ., ).…”

Section: Discussionmentioning

confidence: 92%

“…Harsh sea‐surface conditions likely prevented the development of phototrophic dinocyst taxa in this area, while primary producers such as diatoms may account for the presence of heterotrophic dinocyst taxa. Previous studies (e.g., Ouellet‐Bernier et al ., ; Gibb et al ., ) in the region of Disko Bugt have also observed dinocyst assemblages dominated by heterotrophic taxa prior to 7300 and 7400 cal a bp, respectively. Besides, Jennings et al .…”

Section: Discussionmentioning

confidence: 99%

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Evolution of sea‐surface conditions on the northwestern Greenland margin during the Holocene

Caron

Rochon

Montero‐Serrano

et al. 2019

J Quaternary Science

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Reconstructions of sea‐surface conditions during the Holocene were achieved on two sediment cores from the northwest Greenland margin (AMD14‐204) and Kane Basin (AMD14‐Kane2B) based on dinoflagellate cyst assemblages. On the northwest Greenland margin, sea‐surface conditions were cold with an extended sea ice cover prior to 7750 cal a bp associated with the end of the deglaciation. A major change occurred around ca. 7750 cal a bp with enhanced influence of warmer water from the West Greenland Current, and optimal sea‐surface conditions were observed around 6000 cal a bp. After 3350 cal a bp, results reflect the establishment of the modern assemblages. In the Kane Basin, sea‐surface conditions were not favourable for dinocyst productivity prior to 7880 cal a bp, as the basin was still largely covered by ice. The presence of warmer water is recorded between 7880 and 7200 cal a bp and the highest primary productivity between 5200 and 2100 cal a bp, but sea‐surface conditions remained cold with an extended sea ice cover throughout the Holocene. Overall, the results from this study revealed the strong influence of meltwater discharges and oceanic current variability on the sea‐surface conditions. Copyright © 2019 John Wiley & Sons, Ltd.

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“…; Gibb et al . ). This implies a widespread freshening and cooling of subsurface waters within the sub‐polar North Atlantic region.…”

Section: Discussionmentioning

confidence: 97%

Subarctic Front migration at the Reykjanes Ridge during the mid‐ to late Holocene: evidence from planktic foraminifera

Perner

Moros

Jansen

et al. 2017

Boreas

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Prins, M. A. 2018 (January): Subarctic Front migration at the Reykjanes Ridge during the mid-to late Holocene: evidence from planktic foraminifera. Boreas, Vol. 47, pp. 175-188. https://doi.org/10.1111/bor.12263. ISSN 0300-9483.Expansion of fresh and sea-ice loaded surface waters from the Arctic Ocean into the sub-polar North Atlantic is suggested to modulate the northward heat transport within the North Atlantic Current (NAC). The Reykjanes Ridge south of Iceland is a suitable area to reconstruct changes in the mid-to late Holocene fresh and sea-ice loaded surface water expansion, which is marked by the Subarctic Front (SAF). Here, shifts in the location of the SAF result from the interaction of freshwater expansion and inflow of warmer and saline (NAC) waters to the Ridge. Using planktic foraminiferal assemblage and concentration data from a marine sediment core on the eastern Reykjanes Ridge elucidates SAF location changes and thus, changes in the water-mass composition (upper~200 m) during the last c. 5.8 ka BP. Our foraminifer data highlight a late Holocene shift (at c. 3.0 ka BP) in water-mass composition at the Reykjanes Ridge, which reflects the occurrence of cooler and fresher surface waters when compared to the midHolocene. We document two phases of SAF presence at the study site: from (i) c. 5.5 to 5.0 ka BP and (ii) c. 2.7 to 1.5 ka BP. Both phases are characterized by marked increases in the planktic foraminiferal concentration, which coincides with freshwater expansions and warm subsurface water conditions within the sub-polar North Atlantic. We link the SAF changes, from c. 2.7 to 1.5 ka BP, to a strengthening of the East Greenland Current and awarming in the NAC, as identified by various studies underlying these two currents. From c. 1.5 ka BP onwards, we record a prominent subsurface cooling and continued occurrence of fresh and sea-ice loaded surface waters at the study site. This implies that the SAF migrated to the southeast of our core site during the last millennium.

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Diachronous evolution of sea surface conditions in the Labrador Sea and Baffin Bay since the last deglaciation

Cited by 56 publications

References 92 publications

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Deglaciation and ice shelf development at the northeast margin of the Laurentide Ice Sheet during the Younger Dryas chronozone

Evolution of sea‐surface conditions on the northwestern Greenland margin during the Holocene

Subarctic Front migration at the Reykjanes Ridge during the mid‐ to late Holocene: evidence from planktic foraminifera

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