Last Glacial ice-sheet dynamics offshore NE Greenland – a case study from Store Koldewey Trough

Olsen, Ingrid Leirvik; Forwick, Matthias; Laberg, Jan Sverre; Rydningen, Tom Arne; Husum, Katrine

doi:10.5194/tc-2019-281

Cited by 3 publications

(11 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…2017; Olsen et al . 2020). The central East Greenland shelf at 69–72°N and at 75°N is so intensively reworked by iceberg scouring that the deposits resemble tills (Dowdeswell et al .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Northeast Greenland: ice‐free shelf edge at 79.4°N around the Last Glacial Maximum 25.5–17.5 ka

Rasmussen

Pearce

Andresen

et al. 2022

Boreas

View full text Add to dashboard Cite

The size of the last glacial ice sheet on the Northeast (NE) Greenland shelf and its interaction with ocean circulation have been the subject of debate. Here we provide insights into the extent of the ice sheet around the Last Glacial Maximum (LGM) and investigate timing and strength of changes in the flow of Atlantic Water. The study is based on a multiproxy investigation of a marine sediment core, gravity core DA17-NG-ST01-019G, from 323-m water depth at the NE Greenland shelf edge at 79.4°N. We present benthic and planktic foraminiferal distribution data, AMS-14 C dates, sedimentological (ice-rafted debris (IRD) and grain sizes), and geochemical (XRF) data in combination with geophysical (sub-bottom profiler) data. The oldest sediments at the study site are dated to 25.5-17.5 ka, encompassing the time frame from the beginning of the LGM to the early deglaciation. This part is overlain by sediments from the late deglaciation and Holocene. The deposits dating from the LGM are very rich in both planktic and benthic foraminifera and macrofossils of excellent preservation. The faunas show that the site generally was affected by a strong flow of relatively warm subsurface Atlantic Water during the LGM and Early Holocene. Conditions turned more polar with cold bottom water flow in the Middle-Late Holocene (c. 7.5 ka to Recent) with presence of mainly agglutinated benthic foraminiferal species. Our data from the LGM also indicate that the deposits were mixed by iceberg scouring, confirmed by the geophysical data showing extensive ploughing of the sediments on the outer shelf area. The results further indicate that the Greenland Ice Sheet did not reach to the edge of the NE Greenland shelf at 79.4°N during the LGM 24-18 ka.

show abstract

“…2017; Olsen et al . 2020). The central East Greenland shelf at 69–72°N and at 75°N is so intensively reworked by iceberg scouring that the deposits resemble tills (Dowdeswell et al .…”

Section: Discussionmentioning

confidence: 99%

“…Olsen et al . 2020). So far, most 14 C dates of marine sediments from the northern part of the NE Greenland shelf indicate Younger Dryas and Holocene ages (Notholt 1998; Evans et al .…”

Section: Discussionmentioning

confidence: 99%

Northeast Greenland: ice‐free shelf edge at 79.4°N around the Last Glacial Maximum 25.5–17.5 ka

Rasmussen

Pearce

Andresen

et al. 2022

Boreas

View full text Add to dashboard Cite

show abstract

“…Marine studies have found evidence for past advancement and retreat of the NGIS along the continental shelf offshore Northeast Greenland (Evans et al, 2009;Winkelmann et al, 2010;Arndt et al, 2015Arndt et al, , 2017Laberg et al, 2017;Arndt, 2018;Olsen et al, 2020). Geomorphological findings in Store Koldewey Trough, a major shelf trough northeast of the study area (Fig.…”

Section: Introductionmentioning

confidence: 95%

Southern outlet of the Northeast Greenland Ice Stream, NE Greenland: post-Last Glacial Maximum response to climate warming

Zoller

Laberg²,

Rydningen³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. The Greenland Ice Sheet (GrIS) responds rapidly to the present climate, therefore, its response to the predicted future warming is of concern. To learn more about this, decoding its behavior during past periods of warmer than present climate is important. However, due to the scarcity of marine studies reconstructing ice sheet conditions on the Northeast Greenland shelf and adjacent fjords including the position of the ice sheet over marine regions, the timing of the deglaciation, and its connection to forcing factors including the Holocene Thermal Maximum (HTM) on NE Greenland remain poorly constrained. This paper aims to use bathymetric data and the analysis of sediment gravity cores to enhance our understanding of ice dynamics of the GrIS near the southern outlet of the Northeast Greenland Ice Stream (NGIS), as well as give insight into the timing of deglaciation and provide a palaeoenvironmental reconstruction of southwestern Dove Bugt and Bessel Fjord since the Last Glacial Maximum (LGM). The swath bathymetry data displayed in this study is the first time the bathymetry for Bessel Fjord has become available. North–south oriented glacial lineations, and the absence of pronounced moraines in southwest Dove Bugt, an inner continental shelf embayment (trough), suggests the southwards and offshore flow of the southern branch of the NGIS, Storstrømmen. Sedimentological data suggests that an ice body, theorized to be the NGIS, may have retreated from the region slightly before ~11.2 ka BP (in the Preboreal period). The seabed morphology of Bessel Fjord, a fjord terminating in southern Dove Bugt, includes numerous basins, separated by thresholds. The position of basin thresholds, which include some recessional moraines, suggest that the GrIS had undergone multiple halts or readvances during deglaciation. A minimum age of 7.2 ka BP is proposed for the retreat of ice to or west of its present-day position in the Bessel Fjord catchment area. This suggests that the GrIS retreated from the marine realm in early Holocene, around the time of the onset of the Holocene Thermal Maximum in this region, a period when the mean July temperature according to Bennike et al., (2008) was at least 2–3 °C higher than at present, and remained at or west of this onshore position for the remainder of the Holocene. The transition from predominantly mud to muddy sand layers in a mid-fjord core at ~4 ka BP may be the result of increased sediment input from nearby and growing ice caps. This shift may suggest that in late Holocene (Meghalayan), a period characterized by a temperature drop to modern values, ice caps in Bessel Fjord fluctuated with greater sensitivity to climatic conditions than the NE sector of the GrIS.

show abstract

“…Depth, temperature, and salinity are the main environmental drivers determine the spatial distribution of marine zooplankton Northeast Greenland. The bathymetry varies considerably between the Fjord, Shelf, and Slope locations (Table 1; Arndt et al 2015;Laberg et al 2017;Olsen et al 2020). Bathymetry and seabed features may redirect water currents on a small geographic scale, thus affecting both the extent of sea-ice cover, freshwater runoff from melting glaciers, and primary production by advection.…”

Section: Habitats and Water Massesmentioning

confidence: 99%

“…2a). The Store Koldewey Island, partly closing Dove Bugt, directs low-salinity glacial waters from Dove Bugt through the Store Koldewey Trough, whereas the Norske Through further north is less affected by freshwater and has colder and more saline waters (Arndt et al 2015;Olsen et al 2020).…”

Section: Habitats and Water Massesmentioning

confidence: 99%

Spatial occurrence and abundance of marine zooplankton in Northeast Greenland

2022

View full text Add to dashboard Cite

We present a large-scale survey of mesozooplankton (size range 0.2–20 mm) across coastal, shelf, and slope locations in Northeast Greenland (latitudes 74–79° N, August 2015 and September 2017). Our study is centred on the Video Plankton Recorder (VPR) for non-invasive in situ observations of taxa distribution and abundance while simultaneously recording oceanographic profiles. A modified WP-2 plankton net (85-μm mesh size) was used primarily not only to verify taxa detected by the VPR but also to make a preliminary comparison of abundance estimates by the two gears. A total of 35 zooplankton taxa were identified with 10 genera alone among copepods (Hexanauplia). Selected taxa from the VPR (N=16) were associated with the temperature-salinity spaces and the chlorophyll a-depth profiles in the study area. From surface to > 900 m depth, the overall temperature and salinity ranged between −1.9 and 6.8 °C and 26.6 and 35.3, respectively. Two copepod genera dominated, i.e. Pseudocalanus prevailed in the upper sub-zero layers in coastal waters whereas Calanus was omnipresent, but mainly abundant in the warmer Atlantic waters at the shelf break. Chlorophyll a levels were in general very low (< 2 mg m-3) and peaked at 30–50 m depth, suggesting post-bloom conditions. Overall, zooplankton abundances tended to increase from the coast towards the slope (9–344×103 individuals m-2). Biodiversity in terms of taxon richness, on the other hand, showed the opposite trend and decreased from 16 taxa at the coast to 5 taxa further offshore.

show abstract

Last Glacial ice-sheet dynamics offshore NE Greenland – a case study from Store Koldewey Trough

Cited by 3 publications

References 73 publications

Northeast Greenland: ice‐free shelf edge at 79.4°N around the Last Glacial Maximum 25.5–17.5 ka

Northeast Greenland: ice‐free shelf edge at 79.4°N around the Last Glacial Maximum 25.5–17.5 ka

Southern outlet of the Northeast Greenland Ice Stream, NE Greenland: post-Last Glacial Maximum response to climate warming

Spatial occurrence and abundance of marine zooplankton in Northeast Greenland

Contact Info

Product

Resources

About