Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland
The exchange of proglacial river water with active layer pore water could alter water chemical compositions in glacial outwash plains and oceanic solute fluxes. To evaluate effects of this exchange, we sampled Watson River and adjacent pore water during the 2013 melt season at two sandurs in western...
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ftuninebromaha:oai:digitalcommons.unomaha.edu:geoggeolfacpub-1094 2024-02-04T10:00:47+01:00 Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland Deuerling, Kelly M. Martin, Jonathan B. Martin, Ellen E. Scribner, Cecilia A. 2017-11-20T08:00:00Z application/pdf https://digitalcommons.unomaha.edu/geoggeolfacpub/101 https://digitalcommons.unomaha.edu/context/geoggeolfacpub/article/1094/viewcontent/Hydrologic_exchange_and_chemical_weathering_in_a_proglacial_watershed.pdf unknown DigitalCommons@UNO https://digitalcommons.unomaha.edu/geoggeolfacpub/101 https://digitalcommons.unomaha.edu/context/geoggeolfacpub/article/1094/viewcontent/Hydrologic_exchange_and_chemical_weathering_in_a_proglacial_watershed.pdf http://creativecommons.org/licenses/by-nc-nd/4.0/ Geography and Geology Faculty Publications Hydrologic exchange flows Bank storage Glacial weathering Chemical weathering Proglacial Greenland text 2017 ftuninebromaha 2024-01-07T17:40:53Z The exchange of proglacial river water with active layer pore water could alter water chemical compositions in glacial outwash plains and oceanic solute fluxes. To evaluate effects of this exchange, we sampled Watson River and adjacent pore water during the 2013 melt season at two sandurs in western Greenland; one in Sandflugtdalen and the other near the confluence with Søndre Strømfjord. We measured temperature, specific conductivity, and head gradients between the river and bank over a week-long period at Sandflugtdalen, as well as sediment hydraulic conductivity and chemical compositions of waters from both sites. Specific conductivity of pore water is four to ten times greater than river water as solutes are concentrated from weathering reactions, cryoconcentration, and evaporation. Pore water compositions are predominantly altered by carbonate dissolution and sulfide mineral oxidation. High concentrations of HCO3 and SO4 result from solute recycling and dissolution of secondary Ca-Mg carbonate/sulfate salts initially formed by near-surface evaporation in the summer and at depth by freeze-in of the active layer and cryoconcentration in the winter. High hydraulic conductivity (10−5 to 10−4 m/s) and diurnal fluctuations of river stage during our study caused exchange of river and pore water immediately adjacent to the river channel, with a net loss of river water to the bank. Pore water >6 m from the river continuously flowed away from the river. Approximately 1–8% of the river discharge through the Sandflugtdalen was lost to the river bank during our 6.75 day study based on calculations using Darcy’s Law. Although not sampled, some of this water should discharge to the river during low river stage early and late in the melt season. Elevated pore water solute concentrations in sandurs and water exchange at diurnal and seasonal frequency should impact fluxes of solutes to the ocean, although understanding the magnitude of this effect will require long-term evaluation throughout the melt season. Text Greenland Kangerlussuaq Søndre strømfjord University of Nebraska Omaha: DigitalCommons@UNO Greenland Kangerlussuaq ENVELOPE(-55.633,-55.633,72.633,72.633) Sandflugtdalen ENVELOPE(-50.333,-50.333,67.067,67.067) |
institution |
Open Polar |
collection |
University of Nebraska Omaha: DigitalCommons@UNO |
op_collection_id |
ftuninebromaha |
language |
unknown |
topic |
Hydrologic exchange flows Bank storage Glacial weathering Chemical weathering Proglacial Greenland |
spellingShingle |
Hydrologic exchange flows Bank storage Glacial weathering Chemical weathering Proglacial Greenland Deuerling, Kelly M. Martin, Jonathan B. Martin, Ellen E. Scribner, Cecilia A. Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
topic_facet |
Hydrologic exchange flows Bank storage Glacial weathering Chemical weathering Proglacial Greenland |
description |
The exchange of proglacial river water with active layer pore water could alter water chemical compositions in glacial outwash plains and oceanic solute fluxes. To evaluate effects of this exchange, we sampled Watson River and adjacent pore water during the 2013 melt season at two sandurs in western Greenland; one in Sandflugtdalen and the other near the confluence with Søndre Strømfjord. We measured temperature, specific conductivity, and head gradients between the river and bank over a week-long period at Sandflugtdalen, as well as sediment hydraulic conductivity and chemical compositions of waters from both sites. Specific conductivity of pore water is four to ten times greater than river water as solutes are concentrated from weathering reactions, cryoconcentration, and evaporation. Pore water compositions are predominantly altered by carbonate dissolution and sulfide mineral oxidation. High concentrations of HCO3 and SO4 result from solute recycling and dissolution of secondary Ca-Mg carbonate/sulfate salts initially formed by near-surface evaporation in the summer and at depth by freeze-in of the active layer and cryoconcentration in the winter. High hydraulic conductivity (10−5 to 10−4 m/s) and diurnal fluctuations of river stage during our study caused exchange of river and pore water immediately adjacent to the river channel, with a net loss of river water to the bank. Pore water >6 m from the river continuously flowed away from the river. Approximately 1–8% of the river discharge through the Sandflugtdalen was lost to the river bank during our 6.75 day study based on calculations using Darcy’s Law. Although not sampled, some of this water should discharge to the river during low river stage early and late in the melt season. Elevated pore water solute concentrations in sandurs and water exchange at diurnal and seasonal frequency should impact fluxes of solutes to the ocean, although understanding the magnitude of this effect will require long-term evaluation throughout the melt season. |
format |
Text |
author |
Deuerling, Kelly M. Martin, Jonathan B. Martin, Ellen E. Scribner, Cecilia A. |
author_facet |
Deuerling, Kelly M. Martin, Jonathan B. Martin, Ellen E. Scribner, Cecilia A. |
author_sort |
Deuerling, Kelly M. |
title |
Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
title_short |
Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
title_full |
Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
title_fullStr |
Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
title_full_unstemmed |
Hydrologic exchange and chemical weathering in a proglacial watershed near Kangerlussuaq, west Greenland |
title_sort |
hydrologic exchange and chemical weathering in a proglacial watershed near kangerlussuaq, west greenland |
publisher |
DigitalCommons@UNO |
publishDate |
2017 |
url |
https://digitalcommons.unomaha.edu/geoggeolfacpub/101 https://digitalcommons.unomaha.edu/context/geoggeolfacpub/article/1094/viewcontent/Hydrologic_exchange_and_chemical_weathering_in_a_proglacial_watershed.pdf |
long_lat |
ENVELOPE(-55.633,-55.633,72.633,72.633) ENVELOPE(-50.333,-50.333,67.067,67.067) |
geographic |
Greenland Kangerlussuaq Sandflugtdalen |
geographic_facet |
Greenland Kangerlussuaq Sandflugtdalen |
genre |
Greenland Kangerlussuaq Søndre strømfjord |
genre_facet |
Greenland Kangerlussuaq Søndre strømfjord |
op_source |
Geography and Geology Faculty Publications |
op_relation |
https://digitalcommons.unomaha.edu/geoggeolfacpub/101 https://digitalcommons.unomaha.edu/context/geoggeolfacpub/article/1094/viewcontent/Hydrologic_exchange_and_chemical_weathering_in_a_proglacial_watershed.pdf |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
_version_ |
1789966248690319360 |