Preprints
https://doi.org/10.5194/tc-2021-25
https://doi.org/10.5194/tc-2021-25

  15 Feb 2021

15 Feb 2021

Review status: this preprint is currently under review for the journal TC.

Holocene sea-ice dynamics in Petermann Fjord

Henrieka Detlef1,2, Brendan Reilly3, Anne Jennings4, Mads Mørk Jensen5, Matt O'Regan6, Marianne Glasius5, Jesper Olsen2,7,8, Martin Jakobsson6, and Christof Pearce1,2 Henrieka Detlef et al.
  • 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

Abstract. 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, offering a unique opportunity to study ice-ocean-sea ice interactions at the interface of these realms. 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. Here we use a multi-proxy approach (sea-ice related biomarkers, total organic carbon and its carbon isotopic composition, and benthic and planktonic foraminiferal abundances) to explore Holocene sea-ice dynamics at 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.

The late stages of the regional Holocene Thermal Maximum (5,500–6,900 cal yrs BP) were marked by reduced seasonal sea-ice concentrations in Nares Strait and the lack of ice arch formation. This was followed by a transitional period towards neoglacial cooling from 3,500–5,500 cal yrs BP, where a southern ice arch might have formed, but an early seasonal break-up and late formation likely caused a prolonged open water season and enhanced pelagic productivity in Nares Strait. Between 1,400 cal yrs BP and 3,500 cal yrs BP, regional records suggest the formation of a stable northern ice arch only, with a short period from 2,100–2,500 cal yrs BP where a southern ice arch might have persisted in response to atmospheric cooling spikes. A stable southern ice arch, or even double arching, is also inferred for the period after 1,400 cal yrs BP. Thus, both the inception of a small Petermann ice tongue at ~2,200 cal yrs BP and its rapid expansion at ~600 cal yrs BP are preceded by a transition towards a southern ice arch regime with landfast ice formation in Nares Strait, suggesting a stabilizing effect of landfast sea ice on Petermann Glacier.

Henrieka Detlef et al.

Status: open (until 21 Apr 2021)

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  • RC1: 'Comment on tc-2021-25', Anonymous Referee #1, 14 Apr 2021 reply

Henrieka Detlef et al.

Henrieka Detlef et al.

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Short summary
Here we examine the mid-to-late Holocene sea-ice dynamics in Nares Strait and their implications for the late Holocene re-advance of the floating part of Petermann Glacier. We propose that the historically observed sea-ice dynamics are a relatively recent feature, while most of the mid-Holocene was marked by variable sea-ice conditions in Nares Strait. Nonetheless, major advances of the Petermann ice tongue were preceded by a shift towards harsher sea-ice conditions in Nares Strait.