Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N
International audience High-resolution records of opal, carbonate, and torrigenous fluxes have been obtained from a highsedimentation rate core (MD84-527: 43'50'S; 51'19'E; 3269 m) by normalization to $^{230}$Th. This method estimates paleofluxes to the seafloor on a point-by-poi...
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ftccsdartic:oai:HAL:hal-03584506v1 2023-05-15T18:25:58+02:00 Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N Francois, Roger Bacon, Michael Altabet, Mark Labeyrie, Laurent Woods Hole Oceanographic Institution (WHOI) Centre des Faibles Radioactivités Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS) 1993-10 https://hal.science/hal-03584506 https://hal.science/hal-03584506/document https://hal.science/hal-03584506/file/Paleoceanography%20-%20October%201993%20-%20Francois%20-%20Glacial%20interglacial%20changes%20in%20sediment%20rain%20rate%20in%20the%20SW%20Indian%20Sector%20of.pdf https://doi.org/10.1029/93PA00784 en eng HAL CCSD American Geophysical Union info:eu-repo/semantics/altIdentifier/doi/10.1029/93PA00784 hal-03584506 https://hal.science/hal-03584506 https://hal.science/hal-03584506/document https://hal.science/hal-03584506/file/Paleoceanography%20-%20October%201993%20-%20Francois%20-%20Glacial%20interglacial%20changes%20in%20sediment%20rain%20rate%20in%20the%20SW%20Indian%20Sector%20of.pdf doi:10.1029/93PA00784 info:eu-repo/semantics/OpenAccess ISSN: 0883-8305 Paleoceanography https://hal.science/hal-03584506 Paleoceanography, 1993, 8 (5), pp.611-629. ⟨10.1029/93PA00784⟩ [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment info:eu-repo/semantics/article Journal articles 1993 ftccsdartic https://doi.org/10.1029/93PA00784 2023-02-12T15:11:02Z International audience High-resolution records of opal, carbonate, and torrigenous fluxes have been obtained from a highsedimentation rate core (MD84-527: 43'50'S; 51'19'E; 3269 m) by normalization to $^{230}$Th. This method estimates paleofluxes to the seafloor on a point-by-point basis and distinguishes changes in sediment accumulation due to variations in vertical rain rates from those due to changes in syndepositional sediment redistribution by bottom currents. We also measured sediment $\delta^{15}$N to evaluate the changes in nitrate utilization in the overlying surface waters associated with paleoflux variations. Our results show that opal accumulation rates on the seafloor during the Holocene and stage 3, based on $^{14}$C dating, were respectively tenfold and fivefold higher than the vertical rain rates, At this particular location, changes in opal accumulation on the seafloor appear to be mainly controlled by sediment redistribution by bottom currants rather than variations in opal fluxes from the overlying water column. Correction for syndeposifional sediment redistribution and the improved time resolution that can be achieved by normalization to $^{230}$Th disclose important variations in opal rain rates. We found relatively high but variable opal paleofiux during stage 3, with two maxima centered at 36 and 30 kyr B.P., low opal paleofiux during stage 2 and deglaciafion and a pronounced maximum during the early Holocene, We interpret this record as reflecting variations in opal production rates associated with climateinduced latitudinal migration of the southern ocean frontal system. Sediments deposited during periods of high opal paleofiux also have high authigenic U concentrations, suggesting more reducing conditions in the sediment, and high Pa-231/Th-230 ratios, suggesting increased scavenging from the water colunto. Sediment $\delta^{15}$N is circa 1.5 per mil higher during isotopic stage 2 and deglaciation. The low opal rain rates recorded during that period appear to have been associated ... Article in Journal/Newspaper Southern Ocean Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Indian Southern Ocean Paleoceanography 8 5 611 629 |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment Francois, Roger Bacon, Michael Altabet, Mark Labeyrie, Laurent Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces environment |
description |
International audience High-resolution records of opal, carbonate, and torrigenous fluxes have been obtained from a highsedimentation rate core (MD84-527: 43'50'S; 51'19'E; 3269 m) by normalization to $^{230}$Th. This method estimates paleofluxes to the seafloor on a point-by-point basis and distinguishes changes in sediment accumulation due to variations in vertical rain rates from those due to changes in syndepositional sediment redistribution by bottom currents. We also measured sediment $\delta^{15}$N to evaluate the changes in nitrate utilization in the overlying surface waters associated with paleoflux variations. Our results show that opal accumulation rates on the seafloor during the Holocene and stage 3, based on $^{14}$C dating, were respectively tenfold and fivefold higher than the vertical rain rates, At this particular location, changes in opal accumulation on the seafloor appear to be mainly controlled by sediment redistribution by bottom currants rather than variations in opal fluxes from the overlying water column. Correction for syndeposifional sediment redistribution and the improved time resolution that can be achieved by normalization to $^{230}$Th disclose important variations in opal rain rates. We found relatively high but variable opal paleofiux during stage 3, with two maxima centered at 36 and 30 kyr B.P., low opal paleofiux during stage 2 and deglaciafion and a pronounced maximum during the early Holocene, We interpret this record as reflecting variations in opal production rates associated with climateinduced latitudinal migration of the southern ocean frontal system. Sediments deposited during periods of high opal paleofiux also have high authigenic U concentrations, suggesting more reducing conditions in the sediment, and high Pa-231/Th-230 ratios, suggesting increased scavenging from the water colunto. Sediment $\delta^{15}$N is circa 1.5 per mil higher during isotopic stage 2 and deglaciation. The low opal rain rates recorded during that period appear to have been associated ... |
author2 |
Woods Hole Oceanographic Institution (WHOI) Centre des Faibles Radioactivités Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Francois, Roger Bacon, Michael Altabet, Mark Labeyrie, Laurent |
author_facet |
Francois, Roger Bacon, Michael Altabet, Mark Labeyrie, Laurent |
author_sort |
Francois, Roger |
title |
Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
title_short |
Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
title_full |
Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
title_fullStr |
Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
title_full_unstemmed |
Glacial/interglacial changes in sediment rain rate in the SW Indian sector of subantarctic waters as recorded by $^{230}$Th, $^{231}$Pa, U, and $\delta^{15}$N |
title_sort |
glacial/interglacial changes in sediment rain rate in the sw indian sector of subantarctic waters as recorded by $^{230}$th, $^{231}$pa, u, and $\delta^{15}$n |
publisher |
HAL CCSD |
publishDate |
1993 |
url |
https://hal.science/hal-03584506 https://hal.science/hal-03584506/document https://hal.science/hal-03584506/file/Paleoceanography%20-%20October%201993%20-%20Francois%20-%20Glacial%20interglacial%20changes%20in%20sediment%20rain%20rate%20in%20the%20SW%20Indian%20Sector%20of.pdf https://doi.org/10.1029/93PA00784 |
geographic |
Indian Southern Ocean |
geographic_facet |
Indian Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_source |
ISSN: 0883-8305 Paleoceanography https://hal.science/hal-03584506 Paleoceanography, 1993, 8 (5), pp.611-629. ⟨10.1029/93PA00784⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1029/93PA00784 hal-03584506 https://hal.science/hal-03584506 https://hal.science/hal-03584506/document https://hal.science/hal-03584506/file/Paleoceanography%20-%20October%201993%20-%20Francois%20-%20Glacial%20interglacial%20changes%20in%20sediment%20rain%20rate%20in%20the%20SW%20Indian%20Sector%20of.pdf doi:10.1029/93PA00784 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1029/93PA00784 |
container_title |
Paleoceanography |
container_volume |
8 |
container_issue |
5 |
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op_container_end_page |
629 |
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1766207736359419904 |