Gypsum crystals observed in experimental and natural sea ice

Authors

  • N.-X. Geilfus,

    Corresponding author
    1. Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
    2. Arctic Research Centre, Aarhus University, Aarhus, Denmark
    • Corresponding author: N.-X. Geilfus, Arctic Research Centre, Aarhus University, Aarhus, 8000, Denmark. (Geilfus@biology.au.dk)

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  • R. J. Galley,

    1. Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
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  • M. Cooper,

    1. Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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  • N. Halden,

    1. Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
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  • A. Hare,

    1. Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
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  • F. Wang,

    1. Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
    2. Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, Canada
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  • D. H. Søgaard,

    1. Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
    2. Department of biology, University of Southern Denmark, Odense, Denmark
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  • S. Rysgaard

    1. Centre for Earth Observation Science, University of Manitoba, Winnipeg, Manitoba, Canada
    2. Arctic Research Centre, Aarhus University, Aarhus, Denmark
    3. Department of Geological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
    4. Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
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Abstract

[1] Although gypsum has been predicted to precipitate in sea ice, it has never been observed. Here we provide the first report on gypsum precipitation in both experimental and natural sea ice. Crystals were identified by X-ray diffraction analysis. Based on their apparent distinguishing characteristics, the gypsum crystals were identified as being authigenic. The FREeZing CHEMistry (FREZCHEM) model results support our observations of both gypsum and ikaite precipitation at typical in situ sea ice temperatures and confirms the “Gitterman pathway” where gypsum is predicted to precipitate. The occurrence of authigenic gypsum in sea ice during its formation represents a new observation of precipitate formation and potential marine deposition in polar seas.

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