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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Earth Sci. | doi: 10.3389/feart.2019.00299

Weathering dynamics under contrasting Greenland Ice Sheet catchments

  • 1Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, United Kingdom
  • 2Florida State University, United States
  • 3University of Bristol, United Kingdom
  • 4German Research Centre for Geosciences, Helmholtz Centre Potsdam, Germany
  • 5School of Civil Engineering & Geosciences, Newcastle University, United Kingdom
  • 6Department of Environmental Sciences, Western Norway University of Applied Sciences, Norway
  • 7Department of Geosciences & Natural Resource Management, University of Copenhagen, Denmark
  • 8Geological Survey of Denmark and Greenland, Denmark
  • 9Department of Microbiology and Immunology, University of British Columbia, Canada
  • 10School of Geosciences, University of Edinburgh, United Kingdom

Chemical weathering dynamics in Greenland Ice Sheet (GrIS) catchments are largely unknown, due to a scarcity of field data. This paper presents the most comprehensive study to date of chemical weathering rates from four GrIS catchments of contrasting size. Cationic denudation rates varied greatly between catchments studied (2.6 to 37.6 tons km-2 a-1, world mean = 11.9 tons km -2 a -1), but were of the same order of magnitude to the world non-glacial riverine mean, and are greater than those documented in some major temperate rivers catchments (e.g. Mississippi (1.3 tons km-2 a-1) and Nile (0.4 tons km-2 a-1) rivers). These high chemical denudation rates indicate that the GrIS is a potential source of solute to downstream environments. Dissolved silica yields, indicative of silicate weathering rates, also varied by an order of magnitude, with upper values similar to the world mean (0.2 to 3.8 tons km-2 a-1, world mean = 3.53 tons km-2 a-1). Elevated chemical weathering rates in GrIS catchments are strongly influenced by the specific discharge, which drives flushing of the subglacial environment and physical erosion of the ice sheet bed. The direct relationship between specific discharge and chemical denudation rates supports the hypothesis that Greenland Ice Sheet chemical weathering rates and solute fluxes are likely to increase with enhanced melt rates in a warming climate.

Keywords: Solute fluxes, Cations, silica, Weathering, Denudation rates

Received: 09 Dec 2018; Accepted: 30 Oct 2019.

Copyright: © 2019 Urra, Wadham, Hawkings, Telling, Hatton, Yde, Hasholt, van As, Bhatia and Nienow. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: PhD. Alejandra Urra, University of Bristol, Bristol Glaciology Centre, School of Geographical Sciences, Bristol, United Kingdom, ale.urragallardo@bristol.ac.uk