Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean
We investigate the evolution of Cenozoic climate and ice volume as evidenced by the oxygen isotopic composition of seawater (delta18Osw) derived from benthic foraminiferal Mg/Ca ratios to constrain the temperature effect contained in foraminiferal delta18O values. We have constructed two benthic for...
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ftpangaea:oai:pangaea.de:doi:10.1594/PANGAEA.708305 2023-05-15T13:42:09+02:00 Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean Billups, Katharina Schrag, Daniel P MEDIAN LATITUDE: -39.152667 * MEDIAN LONGITUDE: 57.922950 * SOUTH-BOUND LATITUDE: -64.517000 * WEST-BOUND LONGITUDE: 3.100150 * NORTH-BOUND LATITUDE: -17.023667 * EAST-BOUND LONGITUDE: 88.181133 * DATE/TIME START: 1987-01-15T00:00:00 * DATE/TIME END: 1988-06-05T00:00:00 2003-12-04 application/zip, 6 datasets https://doi.pangaea.de/10.1594/PANGAEA.708305 https://doi.org/10.1594/PANGAEA.708305 en eng PANGAEA https://doi.pangaea.de/10.1594/PANGAEA.708305 https://doi.org/10.1594/PANGAEA.708305 CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess CC-BY Supplement to: Billups, Katharina; Schrag, Daniel P (2003): Application of benthic foraminiferal Mg/Ca ratios to questions of Cenozoic climate change. Earth and Planetary Science Letters, 209(1-2), 181-195, https://doi.org/10.1016/S0012-821X(03)00067-0 113-689 121-757 COMPCORE Composite Core Joides Resolution Leg113 Leg121 Ocean Drilling Program ODP South Atlantic Ocean South Indian Ridge South Indian Ocean Dataset 2003 ftpangaea https://doi.org/10.1594/PANGAEA.708305 https://doi.org/10.1016/S0012-821X(03)00067-0 2023-01-20T07:31:17Z We investigate the evolution of Cenozoic climate and ice volume as evidenced by the oxygen isotopic composition of seawater (delta18Osw) derived from benthic foraminiferal Mg/Ca ratios to constrain the temperature effect contained in foraminiferal delta18O values. We have constructed two benthic foraminiferal Mg/Ca records from intermediate water depth sites (Ocean Drilling Program sites 757 and 689 from the subtropical Indian Ocean and the Weddell Sea, respectively). Together with the previously published composite record of Lear et al. (2002, doi:10.1126/science.287.5451.269) and the Neogene record from the Southern Ocean of Billups and Schrag (2002, doi:10.1029/2000PA000567), we obtain three, almost complete representations of the delta18Osw for the past 52 Myr. We discuss the sensitivity of early Cenozoic Mg/Ca-derived paleotemperatures (and hence the delta18Osw) to assumptions about seawater Mg/Ca ratios. We find that during the middle Eocene (~ 49-40 Ma), modern seawater ratios yield Mg/Ca-derived temperatures that are in good agreement with the oxygen isotope paleothermometer assuming ice-free conditions. Intermediate waters cooled during the middle Eocene reaching minimum temperatures by 40 Ma. The corresponding delta18Osw reconstructions support ice growth on Antarctica beginning by at least 40 Ma. At the Eocene/Oligocene boundary, Mg/Ca ratios (and hence temperatures) from Weddell Sea site 689 display a well-defined maximum. We caution against a paleoclimatic significance of this result and put forth that the partitioning coefficient of Mg in benthic foraminifera may be sensitive to factors other than temperature. Throughout the remainder of the Cenozoic, the temporal variability among delta18Osw records is similar and similar to longer-term trends in the benthic foraminiferal delta18O record. An exception occurs during the Pliocene when delta18Osw minima in two of the three records suggest reductions in global ice volume that are not apparent in foraminiferal delta18O records, which provides a new ... Dataset Antarc* Antarctica South Atlantic Ocean Southern Ocean Weddell Sea PANGAEA - Data Publisher for Earth & Environmental Science Indian Southern Ocean Weddell Weddell Sea ENVELOPE(3.100150,88.181133,-17.023667,-64.517000) |
institution |
Open Polar |
collection |
PANGAEA - Data Publisher for Earth & Environmental Science |
op_collection_id |
ftpangaea |
language |
English |
topic |
113-689 121-757 COMPCORE Composite Core Joides Resolution Leg113 Leg121 Ocean Drilling Program ODP South Atlantic Ocean South Indian Ridge South Indian Ocean |
spellingShingle |
113-689 121-757 COMPCORE Composite Core Joides Resolution Leg113 Leg121 Ocean Drilling Program ODP South Atlantic Ocean South Indian Ridge South Indian Ocean Billups, Katharina Schrag, Daniel P Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
topic_facet |
113-689 121-757 COMPCORE Composite Core Joides Resolution Leg113 Leg121 Ocean Drilling Program ODP South Atlantic Ocean South Indian Ridge South Indian Ocean |
description |
We investigate the evolution of Cenozoic climate and ice volume as evidenced by the oxygen isotopic composition of seawater (delta18Osw) derived from benthic foraminiferal Mg/Ca ratios to constrain the temperature effect contained in foraminiferal delta18O values. We have constructed two benthic foraminiferal Mg/Ca records from intermediate water depth sites (Ocean Drilling Program sites 757 and 689 from the subtropical Indian Ocean and the Weddell Sea, respectively). Together with the previously published composite record of Lear et al. (2002, doi:10.1126/science.287.5451.269) and the Neogene record from the Southern Ocean of Billups and Schrag (2002, doi:10.1029/2000PA000567), we obtain three, almost complete representations of the delta18Osw for the past 52 Myr. We discuss the sensitivity of early Cenozoic Mg/Ca-derived paleotemperatures (and hence the delta18Osw) to assumptions about seawater Mg/Ca ratios. We find that during the middle Eocene (~ 49-40 Ma), modern seawater ratios yield Mg/Ca-derived temperatures that are in good agreement with the oxygen isotope paleothermometer assuming ice-free conditions. Intermediate waters cooled during the middle Eocene reaching minimum temperatures by 40 Ma. The corresponding delta18Osw reconstructions support ice growth on Antarctica beginning by at least 40 Ma. At the Eocene/Oligocene boundary, Mg/Ca ratios (and hence temperatures) from Weddell Sea site 689 display a well-defined maximum. We caution against a paleoclimatic significance of this result and put forth that the partitioning coefficient of Mg in benthic foraminifera may be sensitive to factors other than temperature. Throughout the remainder of the Cenozoic, the temporal variability among delta18Osw records is similar and similar to longer-term trends in the benthic foraminiferal delta18O record. An exception occurs during the Pliocene when delta18Osw minima in two of the three records suggest reductions in global ice volume that are not apparent in foraminiferal delta18O records, which provides a new ... |
format |
Dataset |
author |
Billups, Katharina Schrag, Daniel P |
author_facet |
Billups, Katharina Schrag, Daniel P |
author_sort |
Billups, Katharina |
title |
Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
title_short |
Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
title_full |
Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
title_fullStr |
Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
title_full_unstemmed |
Mg/Ca ratios of Cenozoic benthic foraminifera from the Indian and South Atlantic Ocean |
title_sort |
mg/ca ratios of cenozoic benthic foraminifera from the indian and south atlantic ocean |
publisher |
PANGAEA |
publishDate |
2003 |
url |
https://doi.pangaea.de/10.1594/PANGAEA.708305 https://doi.org/10.1594/PANGAEA.708305 |
op_coverage |
MEDIAN LATITUDE: -39.152667 * MEDIAN LONGITUDE: 57.922950 * SOUTH-BOUND LATITUDE: -64.517000 * WEST-BOUND LONGITUDE: 3.100150 * NORTH-BOUND LATITUDE: -17.023667 * EAST-BOUND LONGITUDE: 88.181133 * DATE/TIME START: 1987-01-15T00:00:00 * DATE/TIME END: 1988-06-05T00:00:00 |
long_lat |
ENVELOPE(3.100150,88.181133,-17.023667,-64.517000) |
geographic |
Indian Southern Ocean Weddell Weddell Sea |
geographic_facet |
Indian Southern Ocean Weddell Weddell Sea |
genre |
Antarc* Antarctica South Atlantic Ocean Southern Ocean Weddell Sea |
genre_facet |
Antarc* Antarctica South Atlantic Ocean Southern Ocean Weddell Sea |
op_source |
Supplement to: Billups, Katharina; Schrag, Daniel P (2003): Application of benthic foraminiferal Mg/Ca ratios to questions of Cenozoic climate change. Earth and Planetary Science Letters, 209(1-2), 181-195, https://doi.org/10.1016/S0012-821X(03)00067-0 |
op_relation |
https://doi.pangaea.de/10.1594/PANGAEA.708305 https://doi.org/10.1594/PANGAEA.708305 |
op_rights |
CC-BY-3.0: Creative Commons Attribution 3.0 Unported Access constraints: unrestricted info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/PANGAEA.708305 https://doi.org/10.1016/S0012-821X(03)00067-0 |
_version_ |
1766163423928778752 |