EGU22-4347, updated on 27 Mar 2022
https://doi.org/10.5194/egusphere-egu22-4347
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Retreat of the Northeast Greenland ice stream during the last glacial termination - a case study from Norske Trough

Adrián López-Quirós1, Katrine J. Andresen1, Joanna Davies1, Tuomas Junna1, Tove Nielsen2, Christof Pearce1, and Marit-Solveig Seidenkrantz1
Adrián López-Quirós et al.
  • 1Department of Geoscience, Aarhus University, Høegh-Guldbergs Gade 2, 8000 Aarhus C, Denmark (alquiros@geo.au.dk)
  • 2Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350 Copenhagen K, Denmark

The Greenland Ice Sheet (GIS), the second largest ice sheet on Earth, has experienced a dramatic ice mass reduction during the last decades, coincident with global warming and an increase in atmospheric CO2. About 16% of the GIS is currently drained via marine terminating glaciers, mostly through the Northeast Greenland Ice Stream (NEGIS; with ~12%). Two cross-shelf troughs (Norske and Westwind troughs) served as drainage pathways of the NEGIS. According to numerical ice-sheet models, a whole meltdown of the GIS may cause a global sea−level rise of >7 m, causing permanent damage to the environment and countless economic impacts on our coastal society. In order to better understand the processes driving these present changes, studies of the development of glaciers/glacial troughs and ice sheets in response to past climate changes are required for testing numerical models that seek to predict ice-sheet response to anthropogenic climate change.

In this study, high-resolution INNOMAR sediment subbottom profiler data combined to multi-proxy analyses of gravity core DA17-NG-ST10-117G, obtained from Norske Trough during the NorthGreen17 expedition, are investigated. Multi-proxy data derived from the sediment gravity core include 14C-derived ages, descriptions of sedimentary units, compositional variability of ice-rafted debris, and continuous logging of magnetic susceptibility and micro-XRF core scanning. In Norske Trough, submarine glacial landforms indicate that ice sheet retreat to the outer middle shelf after the Last Glacial Maximum (LGM) was stepwise, with phases of grounding line stabilization, while ice sheet retreat from the middle shelf to the coastline during deglaciation was fast. Sedimentological evidence at our recorded coring site captures the transition from sub–ice stream (subglacial) environments to proximal (proglacial)/distal glaciomarine conditions during the LGM to Holocene recession. In addition, preliminary foraminifera analysis indicates warmer recirculating Atlantic Water on the middle Norske Trough immediately on deglaciation, suggesting that oceanic forcing very likely played a significant role during the retreat of the ice margin. This presentation will include a comprehensive comparison of the spatio-temporal sedimentation patterns across the Norske Trough.

How to cite: López-Quirós, A., Andresen, K. J., Davies, J., Junna, T., Nielsen, T., Pearce, C., and Seidenkrantz, M.-S.: Retreat of the Northeast Greenland ice stream during the last glacial termination - a case study from Norske Trough, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4347, https://doi.org/10.5194/egusphere-egu22-4347, 2022.

Corresponding displays formerly uploaded have been withdrawn.