Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states
The sensitivities of benthic foraminiferal Mg/Ca and Li/Ca to bottom water temperature and carbonate saturation state have recently been assessed. Here we present a new approach that uses paired Mg/Ca and Li/Ca records to calculate simultaneous changes in temperature and saturation state. Using prev...
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American Geophysical Union
2010
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:11547 2023-05-15T13:39:53+02:00 Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states Lear, Caroline Helen Mawbey, Elaine M. Rosenthal, Yair 2010 application/pdf https://orca.cardiff.ac.uk/id/eprint/11547/ https://doi.org/10.1029/2009PA001880 https://orca.cardiff.ac.uk/id/eprint/11547/1/Lear%202010.pdf en eng American Geophysical Union https://orca.cardiff.ac.uk/id/eprint/11547/1/Lear%202010.pdf Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430, Mawbey, Elaine M. https://orca.cardiff.ac.uk/view/cardiffauthors/A127259H.html and Rosenthal, Yair 2010. Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states. Paleoceanography 25 (4) , PA4215. 10.1029/2009PA001880 https://doi.org/10.1029/2009PA001880 file https://orca.cardiff.ac.uk/11547/1/Lear%202010.pdf doi:10.1029/2009PA001880 GC Oceanography QE Geology Article PeerReviewed 2010 ftunivcardiff https://doi.org/10.1029/2009PA001880 2022-10-20T22:34:39Z The sensitivities of benthic foraminiferal Mg/Ca and Li/Ca to bottom water temperature and carbonate saturation state have recently been assessed. Here we present a new approach that uses paired Mg/Ca and Li/Ca records to calculate simultaneous changes in temperature and saturation state. Using previously published records, we first use this approach to document a cooling of deep ocean waters associated with the establishment of the Antarctic ice sheet at the Eocene-Oligocene climate transition. We then apply this approach to new records of the Middle Miocene Climate Transition from ODP Site 761 to estimate variations in bottom water temperature and the oxygen isotopic composition of seawater. We estimate that the oxygen isotopic composition of seawater varied by ∼1‰ between the deglacial extreme of the Miocene Climatic Optimum and the glacial maximum following the Middle Miocene Climate Transition, indicating large amplitude variations in ice volume. However, the longer-term change between 15.3 and 12.5 Ma is marked by a ∼1°C cooling of deep waters, and an increase in the oxygen isotopic composition of seawater of ∼0.6‰. We find that bottom water saturation state increased in the lead up to the Middle Miocene Climate Transition and decreased shortly after. This supports decreasing pCO2 as a driver for global cooling and ice sheet expansion, in agreement with existing boron isotope and leaf stomatal index CO2 records but in contrast to the published alkenone CO2 records. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Cardiff University: ORCA (Online Research @ Cardiff) Antarctic The Antarctic Paleoceanography 25 4 n/a n/a |
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Open Polar |
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Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
English |
topic |
GC Oceanography QE Geology |
spellingShingle |
GC Oceanography QE Geology Lear, Caroline Helen Mawbey, Elaine M. Rosenthal, Yair Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
topic_facet |
GC Oceanography QE Geology |
description |
The sensitivities of benthic foraminiferal Mg/Ca and Li/Ca to bottom water temperature and carbonate saturation state have recently been assessed. Here we present a new approach that uses paired Mg/Ca and Li/Ca records to calculate simultaneous changes in temperature and saturation state. Using previously published records, we first use this approach to document a cooling of deep ocean waters associated with the establishment of the Antarctic ice sheet at the Eocene-Oligocene climate transition. We then apply this approach to new records of the Middle Miocene Climate Transition from ODP Site 761 to estimate variations in bottom water temperature and the oxygen isotopic composition of seawater. We estimate that the oxygen isotopic composition of seawater varied by ∼1‰ between the deglacial extreme of the Miocene Climatic Optimum and the glacial maximum following the Middle Miocene Climate Transition, indicating large amplitude variations in ice volume. However, the longer-term change between 15.3 and 12.5 Ma is marked by a ∼1°C cooling of deep waters, and an increase in the oxygen isotopic composition of seawater of ∼0.6‰. We find that bottom water saturation state increased in the lead up to the Middle Miocene Climate Transition and decreased shortly after. This supports decreasing pCO2 as a driver for global cooling and ice sheet expansion, in agreement with existing boron isotope and leaf stomatal index CO2 records but in contrast to the published alkenone CO2 records. |
format |
Article in Journal/Newspaper |
author |
Lear, Caroline Helen Mawbey, Elaine M. Rosenthal, Yair |
author_facet |
Lear, Caroline Helen Mawbey, Elaine M. Rosenthal, Yair |
author_sort |
Lear, Caroline Helen |
title |
Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
title_short |
Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
title_full |
Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
title_fullStr |
Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
title_full_unstemmed |
Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states |
title_sort |
cenozoic benthic foraminiferal mg/ca and li/ca records: toward unlocking temperatures and saturation states |
publisher |
American Geophysical Union |
publishDate |
2010 |
url |
https://orca.cardiff.ac.uk/id/eprint/11547/ https://doi.org/10.1029/2009PA001880 https://orca.cardiff.ac.uk/id/eprint/11547/1/Lear%202010.pdf |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_relation |
https://orca.cardiff.ac.uk/id/eprint/11547/1/Lear%202010.pdf Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430, Mawbey, Elaine M. https://orca.cardiff.ac.uk/view/cardiffauthors/A127259H.html and Rosenthal, Yair 2010. Cenozoic benthic foraminiferal Mg/Ca and Li/Ca records: toward unlocking temperatures and saturation states. Paleoceanography 25 (4) , PA4215. 10.1029/2009PA001880 https://doi.org/10.1029/2009PA001880 file https://orca.cardiff.ac.uk/11547/1/Lear%202010.pdf doi:10.1029/2009PA001880 |
op_doi |
https://doi.org/10.1029/2009PA001880 |
container_title |
Paleoceanography |
container_volume |
25 |
container_issue |
4 |
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n/a |
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n/a |
_version_ |
1766125839818162176 |