Holocene sea-ice dynamics in Petermann Fjord
- 1Department of Geoscience, Aarhus University, Høegh-Guldbergs Gade 2, 8000 Aarhus C, Denmark
- 2Arctic Research Centre, Aarhus University, Ny Munkegade 114, 8000 Aarhus C, Denmark
- 3Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, USA
- 4Institute of Arctic and Alpine Research, University of Colorado, Boulder, CO 80309-0450, USA
- 5Department of Chemistry, Aarhus University, Langelandsgade 140, 8000 Aarhus C, Denmark
- 6Department of Geological Sciences, Stockholm University, 106 91 Stockholm, Sweden
- 7Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Aarhus C, Denmark
- 8School of Culture and Society – Centre for Urban Network Evolutions, Moesgård Alle 20, 8270 Højbjerg, Denmark
Today Nares Strait is covered by sea ice for 11 months per year. The seasonal sea-ice regime and formation of landfast ice depend on the development of ice arches. Historically a northern and southern ice arch have been observed in Robeson Channel and Smith Sound, respectively, with only the southern arch leading to a complete freeze up of the strait. In recent decades, the northern arch has become more prominent, indicating a regime shift in Nares Strait sea-ice dynamics with important consequences for the export of ice from the Lincoln Sea, the regional oceanography, and the ecosystem related to the annual opening of the North Water Polynya lee of the southern ice arch. Modelling studies suggest a link between mobile sea ice and enhanced Ekman transport of modified Atlantic Water to Greenland fjord systems bordering Nares Strait. Further, a reduction in the fjords’ fast ice season, in response to Nares Strait sea-ice dynamics, might decrease its buttressing effect on the marine-terminating outlet glaciers in northern Greenland. One such glacier is Petermann Glacier, draining 4% of the Greenland Ice Sheet and terminating in a 48 km long ice tongue in Petermann Fjord.
The Petermann 2015 Expedition to Petermann Fjord and adjacent Hall Basin recovered a transect of cores from Nares Strait to under the 48 km long ice tongue of Petermann glacier. First results suggest that no ice tongue existed in Petermann Fjord for large parts of the Holocene, raising the question of the role of the ocean and the marine cryosphere in the collapse and re-establishment of the ice tongue. We present a multi-proxy study (sea-ice related biomarkers, total organic carbon and its carbon isotopic composition, and benthic and planktonic foraminiferal abundances) exploring the Holocene sea-ice dynamics at site OD1507-03TC-41GC-03PC in outer Petermann Fjord. Our results are in line with a tight coupling of the marine and terrestrial cryosphere in this region and, in connection with other regional sea-ice reconstructions, give insights into the Holocene evolution of ice arches and associated landfast ice in Nares Strait.
How to cite: Detlef, H., Reilly, B., Jennings, A., Mørk jensen, M., O'Regan, M., Glasius, M., Olsen, J., Jakobsson, M., and Pearce, C.: Holocene sea-ice dynamics in Petermann Fjord , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14309, https://doi.org/10.5194/egusphere-egu21-14309, 2021.
