Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada
Recent marine sedimentary deposits and river discharge in two subarctic fjords in Nunatsiavut (Northern Labrador, Canada) have been studied to elucidate patterns and mechanisms of fluvial sediment transfer and accumulation in the fjords, to further our understanding of the longer-term sedimentary re...
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crcansciencepubl:10.1139/e2012-052 2023-12-17T10:30:36+01:00 Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada Bentley, Samuel J. Kahlmeyer, Elisabeth Bustin, Marc R.M. 2012 http://dx.doi.org/10.1139/e2012-052 http://www.nrcresearchpress.com/doi/full-xml/10.1139/e2012-052 http://www.nrcresearchpress.com/doi/pdf/10.1139/e2012-052 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Canadian Journal of Earth Sciences volume 49, issue 10, page 1200-1215 ISSN 0008-4077 1480-3313 General Earth and Planetary Sciences journal-article 2012 crcansciencepubl https://doi.org/10.1139/e2012-052 2023-11-19T13:38:32Z Recent marine sedimentary deposits and river discharge in two subarctic fjords in Nunatsiavut (Northern Labrador, Canada) have been studied to elucidate patterns and mechanisms of fluvial sediment transfer and accumulation in the fjords, to further our understanding of the longer-term sedimentary record. Multibeam and sub-bottom acoustic data and sediment cores were collected in Nachvak and Saglek fjords, within Canada’s Torngat Mountains National Park, as part of the most extensive study of the park’s marine resources to date. Cores were subsampled for X-radiography, grain size, and 210 Pb/ 137 Cs geochronology. Muddy basin sediments within each fjord are bioturbated, indicating circulation of oxygenated bottom water. Depositional fluxes and inventories of 210 Pb indicate efficient marine scavenging of 210 Pb by fine suspended sediments. In Nachvak Fjord, with small rivers and steep, presently glaciated catchments, postglacial and recent sediment accumulation rates are similar, implying relatively constant sedimentation over time. In Saglek Fjord, fed by larger rivers with more extensive catchments that lack glaciers, recent sediment accumulation is more rapid than that averaged over postglacial time. Present mass accumulation rates for the Nachvak Fjord basin are on average 39 000 t·year –1 for the entire basin, and for Saglek 43 000 t·year –1 for the entire basin, with sediment-gravity flows being one likely mechanism for sediment delivery to deep basins. Results collectively suggest that both marine basins are excellent natural sediment traps. Comparison of accumulation rates from 137 Cs and 210 Pb suggest that sediment fluxes to Nachvak Fjord may have decreased slightly over the past ∼130 years. Article in Journal/Newspaper glacier* Subarctic Torngat Mountains national park Canadian Science Publishing (via Crossref) Canada Torngat Mountains ENVELOPE(-63.665,-63.665,59.000,59.000) Canadian Journal of Earth Sciences 49 10 1200 1215 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Earth and Planetary Sciences |
spellingShingle |
General Earth and Planetary Sciences Bentley, Samuel J. Kahlmeyer, Elisabeth Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
topic_facet |
General Earth and Planetary Sciences |
description |
Recent marine sedimentary deposits and river discharge in two subarctic fjords in Nunatsiavut (Northern Labrador, Canada) have been studied to elucidate patterns and mechanisms of fluvial sediment transfer and accumulation in the fjords, to further our understanding of the longer-term sedimentary record. Multibeam and sub-bottom acoustic data and sediment cores were collected in Nachvak and Saglek fjords, within Canada’s Torngat Mountains National Park, as part of the most extensive study of the park’s marine resources to date. Cores were subsampled for X-radiography, grain size, and 210 Pb/ 137 Cs geochronology. Muddy basin sediments within each fjord are bioturbated, indicating circulation of oxygenated bottom water. Depositional fluxes and inventories of 210 Pb indicate efficient marine scavenging of 210 Pb by fine suspended sediments. In Nachvak Fjord, with small rivers and steep, presently glaciated catchments, postglacial and recent sediment accumulation rates are similar, implying relatively constant sedimentation over time. In Saglek Fjord, fed by larger rivers with more extensive catchments that lack glaciers, recent sediment accumulation is more rapid than that averaged over postglacial time. Present mass accumulation rates for the Nachvak Fjord basin are on average 39 000 t·year –1 for the entire basin, and for Saglek 43 000 t·year –1 for the entire basin, with sediment-gravity flows being one likely mechanism for sediment delivery to deep basins. Results collectively suggest that both marine basins are excellent natural sediment traps. Comparison of accumulation rates from 137 Cs and 210 Pb suggest that sediment fluxes to Nachvak Fjord may have decreased slightly over the past ∼130 years. |
author2 |
Bustin, Marc R.M. |
format |
Article in Journal/Newspaper |
author |
Bentley, Samuel J. Kahlmeyer, Elisabeth |
author_facet |
Bentley, Samuel J. Kahlmeyer, Elisabeth |
author_sort |
Bentley, Samuel J. |
title |
Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
title_short |
Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
title_full |
Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
title_fullStr |
Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
title_full_unstemmed |
Patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: Nachvak and Saglek Fjords, Nunatsiavut, Canada |
title_sort |
patterns and mechanisms of fluvial sediment flux and accumulation in two subarctic fjords: nachvak and saglek fjords, nunatsiavut, canada |
publisher |
Canadian Science Publishing |
publishDate |
2012 |
url |
http://dx.doi.org/10.1139/e2012-052 http://www.nrcresearchpress.com/doi/full-xml/10.1139/e2012-052 http://www.nrcresearchpress.com/doi/pdf/10.1139/e2012-052 |
long_lat |
ENVELOPE(-63.665,-63.665,59.000,59.000) |
geographic |
Canada Torngat Mountains |
geographic_facet |
Canada Torngat Mountains |
genre |
glacier* Subarctic Torngat Mountains national park |
genre_facet |
glacier* Subarctic Torngat Mountains national park |
op_source |
Canadian Journal of Earth Sciences volume 49, issue 10, page 1200-1215 ISSN 0008-4077 1480-3313 |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/e2012-052 |
container_title |
Canadian Journal of Earth Sciences |
container_volume |
49 |
container_issue |
10 |
container_start_page |
1200 |
op_container_end_page |
1215 |
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1785583576711954432 |