Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation
We present time-corrected ratios of cosmogenic 10Be to continent-sourced 9Be from two Fe–Mn crusts located in the northwest Atlantic in the vicinity of the origins of Northern Atlantic Deep Water (NADW). These initial 10Be/9Be ratios represent those of the ambient seawater at the time of crust depos...
Published in: | Earth and Planetary Science Letters |
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1999
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Online Access: | https://gfzpublic.gfz-potsdam.de/pubman/item/item_237677 |
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_237677 2023-05-15T17:06:02+02:00 Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation von Blanckenburg, F. O'Nions, R. 0 Pre-GFZ, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum 1999 https://gfzpublic.gfz-potsdam.de/pubman/item/item_237677 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/S0012-821X(99)00028-X https://gfzpublic.gfz-potsdam.de/pubman/item/item_237677 Earth and Planetary Science Letters 550 - Earth sciences info:eu-repo/semantics/article 1999 ftgfzpotsdam https://doi.org/10.1016/S0012-821X(99)00028-X 2022-09-14T05:56:22Z We present time-corrected ratios of cosmogenic 10Be to continent-sourced 9Be from two Fe–Mn crusts located in the northwest Atlantic in the vicinity of the origins of Northern Atlantic Deep Water (NADW). These initial 10Be/9Be ratios represent those of the ambient seawater at the time of crust deposition and are constant through the last 7 Ma. Previously published isotope records of radiogenic Nd and Pb isotopes in these crusts show a decrease in Epsilon Nd and an increase in 206Pb/204Pb over the last 5 Ma. These changes are consistent with a gradual increase in the strength of NADW production, an increase in the Labrador Sea component of NADW, or an increased erosional input into the Labrador Sea. Since the residence time and thus the advective length scales of dissolved Be in deep water lie between those of Nd and Pb, records of 10Be/9Be should, contrary to what has been observed, vary in phase with those of Nd and Pb if these variations are accounted for by changes in paleo-circulation. The observed variations in radiogenic Nd and Pb isotopes are therefore most likely to be explained with an increase in the flux of terrigenous matter in the area of the Labrador Sea, which was possibly associated with ice rafting and selective leaching of Pb isotopes. An increase of the Labrador Sea component that contributes to NADW is also a possibility, but based on the 10Be/9Be data presented here large-scale changes in the thermohaline circulation can be discounted as cause for the radiogenic tracer variations. Article in Journal/Newspaper Labrador Sea NADW Northwest Atlantic GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Earth and Planetary Science Letters 167 3-4 175 182 |
institution |
Open Polar |
collection |
GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
unknown |
topic |
550 - Earth sciences |
spellingShingle |
550 - Earth sciences von Blanckenburg, F. O'Nions, R. Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
topic_facet |
550 - Earth sciences |
description |
We present time-corrected ratios of cosmogenic 10Be to continent-sourced 9Be from two Fe–Mn crusts located in the northwest Atlantic in the vicinity of the origins of Northern Atlantic Deep Water (NADW). These initial 10Be/9Be ratios represent those of the ambient seawater at the time of crust deposition and are constant through the last 7 Ma. Previously published isotope records of radiogenic Nd and Pb isotopes in these crusts show a decrease in Epsilon Nd and an increase in 206Pb/204Pb over the last 5 Ma. These changes are consistent with a gradual increase in the strength of NADW production, an increase in the Labrador Sea component of NADW, or an increased erosional input into the Labrador Sea. Since the residence time and thus the advective length scales of dissolved Be in deep water lie between those of Nd and Pb, records of 10Be/9Be should, contrary to what has been observed, vary in phase with those of Nd and Pb if these variations are accounted for by changes in paleo-circulation. The observed variations in radiogenic Nd and Pb isotopes are therefore most likely to be explained with an increase in the flux of terrigenous matter in the area of the Labrador Sea, which was possibly associated with ice rafting and selective leaching of Pb isotopes. An increase of the Labrador Sea component that contributes to NADW is also a possibility, but based on the 10Be/9Be data presented here large-scale changes in the thermohaline circulation can be discounted as cause for the radiogenic tracer variations. |
author2 |
0 Pre-GFZ, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum |
format |
Article in Journal/Newspaper |
author |
von Blanckenburg, F. O'Nions, R. |
author_facet |
von Blanckenburg, F. O'Nions, R. |
author_sort |
von Blanckenburg, F. |
title |
Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
title_short |
Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
title_full |
Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
title_fullStr |
Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
title_full_unstemmed |
Response of beryllium and radiogenic isotope ratios in Northern Atlantic Deep Water to the onset of northern hemisphere glaciation |
title_sort |
response of beryllium and radiogenic isotope ratios in northern atlantic deep water to the onset of northern hemisphere glaciation |
publishDate |
1999 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_237677 |
genre |
Labrador Sea NADW Northwest Atlantic |
genre_facet |
Labrador Sea NADW Northwest Atlantic |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/S0012-821X(99)00028-X https://gfzpublic.gfz-potsdam.de/pubman/item/item_237677 |
op_doi |
https://doi.org/10.1016/S0012-821X(99)00028-X |
container_title |
Earth and Planetary Science Letters |
container_volume |
167 |
container_issue |
3-4 |
container_start_page |
175 |
op_container_end_page |
182 |
_version_ |
1766060934620512256 |