Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka
We report a nitrogen isotope record (ODP Site 1233) from the southern Chile margin at 41�S. The site is located slightly south of the southern boundary of the Peru�Chile upwelling system and the associated oxygen minimum zone off Peru and northern Chile. We show that our nitrogen isotope record,...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_234868 2023-05-15T13:52:13+02:00 Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka Martinez, P. Lamy, F. Robinson, R. Pichevin, L. Billy, I. 5.2 Climate Dynamics and Landscape Evolution, 5.0 Earth Surface Processes, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum 2006 https://gfzpublic.gfz-potsdam.de/pubman/item/item_234868 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2006.04.009 https://gfzpublic.gfz-potsdam.de/pubman/item/item_234868 Quaternary Science Reviews 550 - Earth sciences info:eu-repo/semantics/article 2006 ftgfzpotsdam https://doi.org/10.1016/j.quascirev.2006.04.009 2022-09-14T05:55:28Z We report a nitrogen isotope record (ODP Site 1233) from the southern Chile margin at 41�S. The site is located slightly south of the southern boundary of the Peru�Chile upwelling system and the associated oxygen minimum zone off Peru and northern Chile. We show that our nitrogen isotope record, from the time interval 0�50 calendar kiloyears before present (ka B.P.), bears an atypical pattern both in shape and timing when compared with records obtained from either the continental margin of the eastern Pacific or the Subantarctic Zone (SAZ) of the Southern Ocean. The δ15N values at Site 1233 are relatively high throughout the record, varying between 9� and 13�. The major features are a pronounced δ15N increase at the beginning of the deglaciation, a maximum from 19 to 10 ka B.P.; thereafter a large decrease during the early Holocene, and millenial scale oscillations showing an Antarctic timing. We propose that the record results from an amalgam of low-latitude and high-latitude processes. Low-latitude processes, including a stronger advection signal of heavy nitrates from the denitrifying zones off Peru and northern Chile, would explain the timing of the deglaciation rise and the heaviest values found over this interval, excluding the Antarctic Cold Reversal period. The overall differences between site 1233 and records from Peru and northwest American margins suggest however that the origin of the δ15N signal off Chile is largely controlled by hydrologic and climatic changes in the Southern Ocean. We propose that the interplay between nutrient demand in the SAZ and latitudinal shifts of hydrologic fronts controlled both the concentrations and the isotopic signature of the remaining nitrate delivered to the Chile margin. Then, the glacial surface waters of the southern Chile margin were likely lower in nitrate concentration and bear a higher δ15N than during interglacial periods. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic Southern Ocean The Antarctic Pacific Quaternary Science Reviews 25 21-22 3017 3028 |
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 Martinez, P. Lamy, F. Robinson, R. Pichevin, L. Billy, I. Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
topic_facet |
550 - Earth sciences |
description |
We report a nitrogen isotope record (ODP Site 1233) from the southern Chile margin at 41�S. The site is located slightly south of the southern boundary of the Peru�Chile upwelling system and the associated oxygen minimum zone off Peru and northern Chile. We show that our nitrogen isotope record, from the time interval 0�50 calendar kiloyears before present (ka B.P.), bears an atypical pattern both in shape and timing when compared with records obtained from either the continental margin of the eastern Pacific or the Subantarctic Zone (SAZ) of the Southern Ocean. The δ15N values at Site 1233 are relatively high throughout the record, varying between 9� and 13�. The major features are a pronounced δ15N increase at the beginning of the deglaciation, a maximum from 19 to 10 ka B.P.; thereafter a large decrease during the early Holocene, and millenial scale oscillations showing an Antarctic timing. We propose that the record results from an amalgam of low-latitude and high-latitude processes. Low-latitude processes, including a stronger advection signal of heavy nitrates from the denitrifying zones off Peru and northern Chile, would explain the timing of the deglaciation rise and the heaviest values found over this interval, excluding the Antarctic Cold Reversal period. The overall differences between site 1233 and records from Peru and northwest American margins suggest however that the origin of the δ15N signal off Chile is largely controlled by hydrologic and climatic changes in the Southern Ocean. We propose that the interplay between nutrient demand in the SAZ and latitudinal shifts of hydrologic fronts controlled both the concentrations and the isotopic signature of the remaining nitrate delivered to the Chile margin. Then, the glacial surface waters of the southern Chile margin were likely lower in nitrate concentration and bear a higher δ15N than during interglacial periods. |
author2 |
5.2 Climate Dynamics and Landscape Evolution, 5.0 Earth Surface Processes, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum |
format |
Article in Journal/Newspaper |
author |
Martinez, P. Lamy, F. Robinson, R. Pichevin, L. Billy, I. |
author_facet |
Martinez, P. Lamy, F. Robinson, R. Pichevin, L. Billy, I. |
author_sort |
Martinez, P. |
title |
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
title_short |
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
title_full |
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
title_fullStr |
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
title_full_unstemmed |
Atypical delta N-15 variations at the southern boundary of the East Pacific oxygen minimum zone over the last 50 ka |
title_sort |
atypical delta n-15 variations at the southern boundary of the east pacific oxygen minimum zone over the last 50 ka |
publishDate |
2006 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_234868 |
geographic |
Antarctic Southern Ocean The Antarctic Pacific |
geographic_facet |
Antarctic Southern Ocean The Antarctic Pacific |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Quaternary Science Reviews |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.quascirev.2006.04.009 https://gfzpublic.gfz-potsdam.de/pubman/item/item_234868 |
op_doi |
https://doi.org/10.1016/j.quascirev.2006.04.009 |
container_title |
Quaternary Science Reviews |
container_volume |
25 |
container_issue |
21-22 |
container_start_page |
3017 |
op_container_end_page |
3028 |
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1766256477837721600 |