Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping
The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a blank spot in ocean and climate history. Paleomagnetic and rock magnetic, geochemical, and sedimentological methods were combined to date and analyze seven middle to late Pleistocene northwe...
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Amer Geophysical Union
2016
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Online Access: | https://archimer.ifremer.fr/doc/00421/53247/54725.pdf https://doi.org/10.1002/2015PA002882 https://archimer.ifremer.fr/doc/00421/53247/ |
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ftarchimer:oai:archimer.ifremer.fr:53247 2023-05-15T13:50:50+02:00 Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping Korff, Lucia Von Dobeneck, Tilo Frederichs, Thomas Kasten, Sabine Kuhn, Gerhard Gersonde, Rainer Diekmann, Bernhard 2016-05 application/pdf https://archimer.ifremer.fr/doc/00421/53247/54725.pdf https://doi.org/10.1002/2015PA002882 https://archimer.ifremer.fr/doc/00421/53247/ eng eng Amer Geophysical Union https://archimer.ifremer.fr/doc/00421/53247/54725.pdf doi:10.1002/2015PA002882 https://archimer.ifremer.fr/doc/00421/53247/ 2016. American Geophysical Union. All Rights Reserved. info:eu-repo/semantics/openAccess restricted use Paleoceanography (0883-8305) (Amer Geophysical Union), 2016-05 , Vol. 31 , N. 5 , P. 600-624 northwest Pacific Ocean carbon trapping magnetite dissolution mid-Pleistocene transition tephra layers abyssal sediments text Publication info:eu-repo/semantics/article 2016 ftarchimer https://doi.org/10.1002/2015PA002882 2021-09-23T20:30:28Z The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a blank spot in ocean and climate history. Paleomagnetic and rock magnetic, geochemical, and sedimentological methods were combined to date and analyze seven middle to late Pleistocene northwest Pacific sediment cores from water depths of 5100 to 5700m. Besides largely coherent tephra layers, the most striking features of these records are nearly magnetite-free zones corresponding to glacial marine isotope stages (MISs) 22, 12, 10, 8, 6, and 2. Magnetite depletion is correlated with organic carbon and quartz content and anticorrelated with biogenic barite and opal content. Within interglacial sections and mid-Pleistocene transition glacial stages MIS 20, 18, 16, and 14, magnetite fractions of detrital, volcanic, and bacterial origin are all well preserved. Such alternating successions of magnetic iron mineral preservation and depletion are known from sapropel-marl cycles, which accumulated under periodically changing bottom water oxygen and redox conditions. In the open central northwest Pacific Ocean, the only conceivable mechanism to cause such abrupt change is a modified glacial bottom water circulation. During all major glaciations since MIS 12, oxygen-depleted Antarctic Bottom Water (AABW)-sourced bottom water seems to have crept into the abyssal northwest Pacific below similar to 5000m depth, thereby changing redox conditions in the sediment, trapping and preserving dissolved and particulate organic matter and, in consequence, reducing and dissolving both, biogenic and detrital magnetite. At deglaciation, a downward progressing oxidation front apparently remineralized and released these sedimentary carbon reservoirs without replenishing the magnetite losses. Article in Journal/Newspaper Antarc* Antarctic Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) Antarctic Pacific Paleoceanography 31 5 600 624 |
institution |
Open Polar |
collection |
Archimer (Archive Institutionnelle de l'Ifremer - Institut français de recherche pour l'exploitation de la mer) |
op_collection_id |
ftarchimer |
language |
English |
topic |
northwest Pacific Ocean carbon trapping magnetite dissolution mid-Pleistocene transition tephra layers abyssal sediments |
spellingShingle |
northwest Pacific Ocean carbon trapping magnetite dissolution mid-Pleistocene transition tephra layers abyssal sediments Korff, Lucia Von Dobeneck, Tilo Frederichs, Thomas Kasten, Sabine Kuhn, Gerhard Gersonde, Rainer Diekmann, Bernhard Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
topic_facet |
northwest Pacific Ocean carbon trapping magnetite dissolution mid-Pleistocene transition tephra layers abyssal sediments |
description |
The carbonate-free abyss of the North Pacific defies most paleoceanographic proxy methods and hence remains a blank spot in ocean and climate history. Paleomagnetic and rock magnetic, geochemical, and sedimentological methods were combined to date and analyze seven middle to late Pleistocene northwest Pacific sediment cores from water depths of 5100 to 5700m. Besides largely coherent tephra layers, the most striking features of these records are nearly magnetite-free zones corresponding to glacial marine isotope stages (MISs) 22, 12, 10, 8, 6, and 2. Magnetite depletion is correlated with organic carbon and quartz content and anticorrelated with biogenic barite and opal content. Within interglacial sections and mid-Pleistocene transition glacial stages MIS 20, 18, 16, and 14, magnetite fractions of detrital, volcanic, and bacterial origin are all well preserved. Such alternating successions of magnetic iron mineral preservation and depletion are known from sapropel-marl cycles, which accumulated under periodically changing bottom water oxygen and redox conditions. In the open central northwest Pacific Ocean, the only conceivable mechanism to cause such abrupt change is a modified glacial bottom water circulation. During all major glaciations since MIS 12, oxygen-depleted Antarctic Bottom Water (AABW)-sourced bottom water seems to have crept into the abyssal northwest Pacific below similar to 5000m depth, thereby changing redox conditions in the sediment, trapping and preserving dissolved and particulate organic matter and, in consequence, reducing and dissolving both, biogenic and detrital magnetite. At deglaciation, a downward progressing oxidation front apparently remineralized and released these sedimentary carbon reservoirs without replenishing the magnetite losses. |
format |
Article in Journal/Newspaper |
author |
Korff, Lucia Von Dobeneck, Tilo Frederichs, Thomas Kasten, Sabine Kuhn, Gerhard Gersonde, Rainer Diekmann, Bernhard |
author_facet |
Korff, Lucia Von Dobeneck, Tilo Frederichs, Thomas Kasten, Sabine Kuhn, Gerhard Gersonde, Rainer Diekmann, Bernhard |
author_sort |
Korff, Lucia |
title |
Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
title_short |
Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
title_full |
Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
title_fullStr |
Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
title_full_unstemmed |
Cyclic magnetite dissolution in Pleistocene sediments of the abyssal northwest Pacific Ocean: Evidence for glacial oxygen depletion and carbon trapping |
title_sort |
cyclic magnetite dissolution in pleistocene sediments of the abyssal northwest pacific ocean: evidence for glacial oxygen depletion and carbon trapping |
publisher |
Amer Geophysical Union |
publishDate |
2016 |
url |
https://archimer.ifremer.fr/doc/00421/53247/54725.pdf https://doi.org/10.1002/2015PA002882 https://archimer.ifremer.fr/doc/00421/53247/ |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Paleoceanography (0883-8305) (Amer Geophysical Union), 2016-05 , Vol. 31 , N. 5 , P. 600-624 |
op_relation |
https://archimer.ifremer.fr/doc/00421/53247/54725.pdf doi:10.1002/2015PA002882 https://archimer.ifremer.fr/doc/00421/53247/ |
op_rights |
2016. American Geophysical Union. All Rights Reserved. info:eu-repo/semantics/openAccess restricted use |
op_doi |
https://doi.org/10.1002/2015PA002882 |
container_title |
Paleoceanography |
container_volume |
31 |
container_issue |
5 |
container_start_page |
600 |
op_container_end_page |
624 |
_version_ |
1766254164315209728 |