Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system
The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant repres...
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ftunivutrecht:oai:dspace.library.uu.nl:1874/330257 2023-07-23T04:17:49+02:00 Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system Vonk, Jorien E. Giosan, Liviu Blusztajn, Jerzy Montlucon, Daniel Graf Pannatier, Elisabeth McIntyre, Cameron Wacker, Lukas Macdonald, Robie W. Yunker, Mark B. Eglinton, Timothy I. Organic geochemistry NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits 2015-12-15 application/pdf https://dspace.library.uu.nl/handle/1874/330257 en eng 0016-7037 https://dspace.library.uu.nl/handle/1874/330257 info:eu-repo/semantics/ClosedAccess Geochemistry and Petrology Article 2015 ftunivutrecht 2023-07-02T01:40:28Z The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant representative of Arctic rivers. Here, we apply sedimentological (grain size, mineral surface area), and organic and inorganic geochemical techniques (%OC, δ13C-OC and δ14C-OC, 143Nd/144Nd, δ2H and δ18O, major and trace elements) on particulate, bank, channel and lake surface sediments from the Mackenzie Delta, as well as on surface sediments from the Mackenzie shelf in the Beaufort Sea. Our data show a hydrodynamic sorting effect resulting in the accumulation of finer-grained sediments in lake and shelf deposits. A general decrease in organic carbon (OC) to mineral surface area ratios from river-to-sea furthermore suggests a loss of mineral-bound terrestrial OC during transport through the delta and deposition on the shelf. The net isotopic value of the terrestrial OC that is lost en route, derived from relationships between δ13C, OC and surface area, is -28.5‰ for δ13C and -417‰ for δ14C. We calculated that OC burial efficiencies are around 55%, which are higher (~20%) than other large river systems such as the Amazon. Old sedimentary OC ages, up to 12 14C-ky, suggest the delivery of both a petrogenic OC source (with an estimated contribution of 19±9%) as well as a pre-aged terrestrial OC source. We calculated the 14C-age of this pre-aged, biogenic, component to be about 6100yrs, or -501‰, which illustrates that terrestrial OC in the watershed can reside for millennia in soils before being released into the river. Surface sediments in lakes across the delta (n=20) showed large variability in %OC (0.92-5.7%) and δ13C (-30.7‰ to -23.5‰). High-closure lakes, flooding only at exceptionally high water levels, hold high sedimentary OC contents (>2.5%) and young biogenic OC with a terrestrial or an autochthonous source ... Article in Journal/Newspaper Arctic Arctic Ocean Beaufort Sea Mackenzie Delta Mackenzie river Mackenzie Shelf Utrecht University Repository Arctic Arctic Ocean Canada Mackenzie Delta ENVELOPE(-136.672,-136.672,68.833,68.833) Mackenzie River |
institution |
Open Polar |
collection |
Utrecht University Repository |
op_collection_id |
ftunivutrecht |
language |
English |
topic |
Geochemistry and Petrology |
spellingShingle |
Geochemistry and Petrology Vonk, Jorien E. Giosan, Liviu Blusztajn, Jerzy Montlucon, Daniel Graf Pannatier, Elisabeth McIntyre, Cameron Wacker, Lukas Macdonald, Robie W. Yunker, Mark B. Eglinton, Timothy I. Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
topic_facet |
Geochemistry and Petrology |
description |
The Mackenzie River in Canada is by far the largest riverine source of sediment and organic carbon (OC) to the Arctic Ocean. Therefore the transport, degradation and burial of OC along the land-to-ocean continuum for this riverine system is important to study both regionally and as a dominant representative of Arctic rivers. Here, we apply sedimentological (grain size, mineral surface area), and organic and inorganic geochemical techniques (%OC, δ13C-OC and δ14C-OC, 143Nd/144Nd, δ2H and δ18O, major and trace elements) on particulate, bank, channel and lake surface sediments from the Mackenzie Delta, as well as on surface sediments from the Mackenzie shelf in the Beaufort Sea. Our data show a hydrodynamic sorting effect resulting in the accumulation of finer-grained sediments in lake and shelf deposits. A general decrease in organic carbon (OC) to mineral surface area ratios from river-to-sea furthermore suggests a loss of mineral-bound terrestrial OC during transport through the delta and deposition on the shelf. The net isotopic value of the terrestrial OC that is lost en route, derived from relationships between δ13C, OC and surface area, is -28.5‰ for δ13C and -417‰ for δ14C. We calculated that OC burial efficiencies are around 55%, which are higher (~20%) than other large river systems such as the Amazon. Old sedimentary OC ages, up to 12 14C-ky, suggest the delivery of both a petrogenic OC source (with an estimated contribution of 19±9%) as well as a pre-aged terrestrial OC source. We calculated the 14C-age of this pre-aged, biogenic, component to be about 6100yrs, or -501‰, which illustrates that terrestrial OC in the watershed can reside for millennia in soils before being released into the river. Surface sediments in lakes across the delta (n=20) showed large variability in %OC (0.92-5.7%) and δ13C (-30.7‰ to -23.5‰). High-closure lakes, flooding only at exceptionally high water levels, hold high sedimentary OC contents (>2.5%) and young biogenic OC with a terrestrial or an autochthonous source ... |
author2 |
Organic geochemistry NWO-VENI: Ancient organic matter that matters: The fate of Siberian Yedoma deposits |
format |
Article in Journal/Newspaper |
author |
Vonk, Jorien E. Giosan, Liviu Blusztajn, Jerzy Montlucon, Daniel Graf Pannatier, Elisabeth McIntyre, Cameron Wacker, Lukas Macdonald, Robie W. Yunker, Mark B. Eglinton, Timothy I. |
author_facet |
Vonk, Jorien E. Giosan, Liviu Blusztajn, Jerzy Montlucon, Daniel Graf Pannatier, Elisabeth McIntyre, Cameron Wacker, Lukas Macdonald, Robie W. Yunker, Mark B. Eglinton, Timothy I. |
author_sort |
Vonk, Jorien E. |
title |
Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
title_short |
Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
title_full |
Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
title_fullStr |
Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
title_full_unstemmed |
Spatial variations in geochemical characteristics of the modern Mackenzie Delta sedimentary system |
title_sort |
spatial variations in geochemical characteristics of the modern mackenzie delta sedimentary system |
publishDate |
2015 |
url |
https://dspace.library.uu.nl/handle/1874/330257 |
long_lat |
ENVELOPE(-136.672,-136.672,68.833,68.833) |
geographic |
Arctic Arctic Ocean Canada Mackenzie Delta Mackenzie River |
geographic_facet |
Arctic Arctic Ocean Canada Mackenzie Delta Mackenzie River |
genre |
Arctic Arctic Ocean Beaufort Sea Mackenzie Delta Mackenzie river Mackenzie Shelf |
genre_facet |
Arctic Arctic Ocean Beaufort Sea Mackenzie Delta Mackenzie river Mackenzie Shelf |
op_relation |
0016-7037 https://dspace.library.uu.nl/handle/1874/330257 |
op_rights |
info:eu-repo/semantics/ClosedAccess |
_version_ |
1772179858934202368 |