Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787
Variations in carbonate flux and dissolution, which occurred in the equatorial Atlantic during the last 24,000 years, have been estimated by a new approach that allows the point-by-point determination of paleofluxes to the seafloor. An unprecedented time resolution can thus be obtained which allows...
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ftdatacite:10.1594/pangaea.727171 2023-05-15T14:05:24+02:00 Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 Francois, Roger Bacon, Michael P Suman, Daniel O 1990 application/zip https://dx.doi.org/10.1594/pangaea.727171 https://doi.pangaea.de/10.1594/PANGAEA.727171 en eng PANGAEA - Data Publisher for Earth & Environmental Science https://dx.doi.org/10.1029/pa005i005p00761 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 CC-BY Gravity corer EN06601 KN11002 Endeavor Knorr article Supplementary Collection of Datasets Collection 1990 ftdatacite https://doi.org/10.1594/pangaea.727171 https://doi.org/10.1029/pa005i005p00761 2022-02-09T13:17:17Z Variations in carbonate flux and dissolution, which occurred in the equatorial Atlantic during the last 24,000 years, have been estimated by a new approach that allows the point-by-point determination of paleofluxes to the seafloor. An unprecedented time resolution can thus be obtained which allows sequencing of the relatively rapid events occurring during deglaciation. The method is based on observations that the flux of unsupported 230Th into deep-sea sediments is nearly independent of the total mass flux and is close to the production rate. Thus excess 230Th activity in sediments can be used as a reference against which fluxes of other sedimentary components can be estimated. The study was conducted at two sites (CearĂ¡ Rise; western equatorial Atlantic, and Sierra Leone Rise; eastern equatorial Atlantic) in cores raised from three different depths at each site. From measurements of 230Th and CaCO3, changes in carbonate flux with time and depth were obtained. A rapid increase in carbonate production, starting at the onset of deglaciation, was found in both areas. This event may have important implications for the postglacial increase in atmospheric CO2 by increasing the global carbonate carbon to organic carbon rain ratio and decreasing the alkalinity of surface waters (and possibly the North Atlantic Deep Water). Increased carbonate dissolution occurred in the two regions during deglaciation, followed by a minimum during mid-Holocene and renewed intensification of dissolution in late Holocene. During the last 16,000 years, carbonate dissolution was consistently more pronounced in the western than in the eastern basin, reflecting the influence of Antarctic Bottom Water in the west. This trend was reversed during stage 2, possibly due to the accumulation of metabolic CO2 below the level of the Romanche Fracture Zone in the eastern basin. Article in Journal/Newspaper Antarc* Antarctic North Atlantic Deep Water North Atlantic DataCite Metadata Store (German National Library of Science and Technology) Antarctic |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
Gravity corer EN06601 KN11002 Endeavor Knorr |
spellingShingle |
Gravity corer EN06601 KN11002 Endeavor Knorr Francois, Roger Bacon, Michael P Suman, Daniel O Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
topic_facet |
Gravity corer EN06601 KN11002 Endeavor Knorr |
description |
Variations in carbonate flux and dissolution, which occurred in the equatorial Atlantic during the last 24,000 years, have been estimated by a new approach that allows the point-by-point determination of paleofluxes to the seafloor. An unprecedented time resolution can thus be obtained which allows sequencing of the relatively rapid events occurring during deglaciation. The method is based on observations that the flux of unsupported 230Th into deep-sea sediments is nearly independent of the total mass flux and is close to the production rate. Thus excess 230Th activity in sediments can be used as a reference against which fluxes of other sedimentary components can be estimated. The study was conducted at two sites (CearĂ¡ Rise; western equatorial Atlantic, and Sierra Leone Rise; eastern equatorial Atlantic) in cores raised from three different depths at each site. From measurements of 230Th and CaCO3, changes in carbonate flux with time and depth were obtained. A rapid increase in carbonate production, starting at the onset of deglaciation, was found in both areas. This event may have important implications for the postglacial increase in atmospheric CO2 by increasing the global carbonate carbon to organic carbon rain ratio and decreasing the alkalinity of surface waters (and possibly the North Atlantic Deep Water). Increased carbonate dissolution occurred in the two regions during deglaciation, followed by a minimum during mid-Holocene and renewed intensification of dissolution in late Holocene. During the last 16,000 years, carbonate dissolution was consistently more pronounced in the western than in the eastern basin, reflecting the influence of Antarctic Bottom Water in the west. This trend was reversed during stage 2, possibly due to the accumulation of metabolic CO2 below the level of the Romanche Fracture Zone in the eastern basin. |
format |
Article in Journal/Newspaper |
author |
Francois, Roger Bacon, Michael P Suman, Daniel O |
author_facet |
Francois, Roger Bacon, Michael P Suman, Daniel O |
author_sort |
Francois, Roger |
title |
Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
title_short |
Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
title_full |
Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
title_fullStr |
Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
title_full_unstemmed |
Radionuclides and accumulation rates of sediments from the equatorial Atlantic, supplement to: Francois, Roger; Bacon, Michael P; Suman, Daniel O (1990): Thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial Atlantic during the last 24,000 years. Paleoceanography, 5(5), 761-787 |
title_sort |
radionuclides and accumulation rates of sediments from the equatorial atlantic, supplement to: francois, roger; bacon, michael p; suman, daniel o (1990): thorium 230 profiling in deep-sea sediments: high resolution records of flux and dissolution of carbonate in the equatorial atlantic during the last 24,000 years. paleoceanography, 5(5), 761-787 |
publisher |
PANGAEA - Data Publisher for Earth & Environmental Science |
publishDate |
1990 |
url |
https://dx.doi.org/10.1594/pangaea.727171 https://doi.pangaea.de/10.1594/PANGAEA.727171 |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic North Atlantic Deep Water North Atlantic |
genre_facet |
Antarc* Antarctic North Atlantic Deep Water North Atlantic |
op_relation |
https://dx.doi.org/10.1029/pa005i005p00761 |
op_rights |
Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode cc-by-3.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/pangaea.727171 https://doi.org/10.1029/pa005i005p00761 |
_version_ |
1766277257768206336 |