δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A
Knowledge of the equatorial thermocline is essential for understanding climate changes in the tropical Pacific. Multispecies planktic foraminiferal analyses provide a way to examine temperature distributions and thus the structure of the thermocline. Although the secular thermocline development has...
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PANGAEA - Data Publisher for Earth & Environmental Science
2020
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Online Access: | https://dx.doi.org/10.1594/pangaea.914391 https://doi.pangaea.de/10.1594/PANGAEA.914391 |
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ftdatacite:10.1594/pangaea.914391 2023-05-15T13:52:56+02:00 δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A Matsui, Hiroki Nishi, Hiroshi Kuroyanagi, Azumi Hayashi, Hiroki Ikehara, Minoru Takashima, Reishi 2020 text/tab-separated-values https://dx.doi.org/10.1594/pangaea.914391 https://doi.pangaea.de/10.1594/PANGAEA.914391 en eng PANGAEA - Data Publisher for Earth & Environmental Science https://dx.doi.org/10.1002/2016pa003058 https://dx.doi.org/10.2204/iodp.proc.320321.209.2013 Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode CC-BY-4.0 CC-BY equatorial Pacific Miocene planktic foraminifera Sample code/label DEPTH, sediment/rock Depth, composite revised, adjusted AGE Paragloborotalia siakensis, δ13C Paragloborotalia siakensis, δ18O Sample comment Dentoglobigerina venezuelana, δ13C Dentoglobigerina venezuelana, δ18O Drilling/drill rig DSDP/ODP/IODP sample designation Exp321 Joides Resolution Integrated Ocean Drilling Program / International Ocean Discovery Program IODP dataset Dataset 2020 ftdatacite https://doi.org/10.1594/pangaea.914391 https://doi.org/10.1002/2016pa003058 https://doi.org/10.2204/iodp.proc.320321.209.2013 2021-11-05T12:55:41Z Knowledge of the equatorial thermocline is essential for understanding climate changes in the tropical Pacific. Multispecies planktic foraminiferal analyses provide a way to examine temperature distributions and thus the structure of the thermocline. Although the secular thermocline development has been documented back to the late Miocene, the early to middle Miocene interval has rarely been examined. In addition, relationships with the dynamic Antarctic ice sheets remain unclear. Here we investigate the vertical thermal gradient in the upper water column at Integrated Ocean Drilling Program Site U1337 in the eastern equatorial Pacific (EEP) throughout the early to middle Miocene (23.1 to 11.7 Ma). The gradient increased over the Miocene Climatic Optimum, whereas it decreased during the East Antarctic Ice Sheet Expansion (EAIE). Comparison of the EEP record with its western equatorial Pacific (WEP) counterpart suggests that sea surface temperature was more stable in the WEP than in the EEP. We further estimated equatorial thermocline from two diagonal gradients between the EEP and the WEP: thermocline shoaled from 16.7 to 15.7 Ma and tilt weakened between 16.5 and 13.8 Ma. The onset of the "Monterey Excursion" and the reduced Antarctic ice sheet volume would have affected thermocline depth and tilt, respectively. Thermocline depth was likely much deeper compared to Pliocene‐to‐modern conditions. Furthermore, a 4‐point‐based distribution of isotherms (4DI index) was used as a metric of the evenness or unevenness of the isotherm distributions. The 4DI index considerably reduced at around the EAIE and other Mi‐events, reflecting the evenly distributed isotherms under a more glaciated Antarctica. : (1) = Analytical precisions are ±0.10‰ for δ¹⁸O and ±0.04‰ for δ¹³C, whereas blank indicates those are ±0.05‰ forδ¹⁸O and ±0.03‰ for δ¹³C. Dataset Antarc* Antarctic Antarctica Ice Sheet DataCite Metadata Store (German National Library of Science and Technology) Antarctic East Antarctic Ice Sheet Pacific |
institution |
Open Polar |
collection |
DataCite Metadata Store (German National Library of Science and Technology) |
op_collection_id |
ftdatacite |
language |
English |
topic |
equatorial Pacific Miocene planktic foraminifera Sample code/label DEPTH, sediment/rock Depth, composite revised, adjusted AGE Paragloborotalia siakensis, δ13C Paragloborotalia siakensis, δ18O Sample comment Dentoglobigerina venezuelana, δ13C Dentoglobigerina venezuelana, δ18O Drilling/drill rig DSDP/ODP/IODP sample designation Exp321 Joides Resolution Integrated Ocean Drilling Program / International Ocean Discovery Program IODP |
spellingShingle |
equatorial Pacific Miocene planktic foraminifera Sample code/label DEPTH, sediment/rock Depth, composite revised, adjusted AGE Paragloborotalia siakensis, δ13C Paragloborotalia siakensis, δ18O Sample comment Dentoglobigerina venezuelana, δ13C Dentoglobigerina venezuelana, δ18O Drilling/drill rig DSDP/ODP/IODP sample designation Exp321 Joides Resolution Integrated Ocean Drilling Program / International Ocean Discovery Program IODP Matsui, Hiroki Nishi, Hiroshi Kuroyanagi, Azumi Hayashi, Hiroki Ikehara, Minoru Takashima, Reishi δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
topic_facet |
equatorial Pacific Miocene planktic foraminifera Sample code/label DEPTH, sediment/rock Depth, composite revised, adjusted AGE Paragloborotalia siakensis, δ13C Paragloborotalia siakensis, δ18O Sample comment Dentoglobigerina venezuelana, δ13C Dentoglobigerina venezuelana, δ18O Drilling/drill rig DSDP/ODP/IODP sample designation Exp321 Joides Resolution Integrated Ocean Drilling Program / International Ocean Discovery Program IODP |
description |
Knowledge of the equatorial thermocline is essential for understanding climate changes in the tropical Pacific. Multispecies planktic foraminiferal analyses provide a way to examine temperature distributions and thus the structure of the thermocline. Although the secular thermocline development has been documented back to the late Miocene, the early to middle Miocene interval has rarely been examined. In addition, relationships with the dynamic Antarctic ice sheets remain unclear. Here we investigate the vertical thermal gradient in the upper water column at Integrated Ocean Drilling Program Site U1337 in the eastern equatorial Pacific (EEP) throughout the early to middle Miocene (23.1 to 11.7 Ma). The gradient increased over the Miocene Climatic Optimum, whereas it decreased during the East Antarctic Ice Sheet Expansion (EAIE). Comparison of the EEP record with its western equatorial Pacific (WEP) counterpart suggests that sea surface temperature was more stable in the WEP than in the EEP. We further estimated equatorial thermocline from two diagonal gradients between the EEP and the WEP: thermocline shoaled from 16.7 to 15.7 Ma and tilt weakened between 16.5 and 13.8 Ma. The onset of the "Monterey Excursion" and the reduced Antarctic ice sheet volume would have affected thermocline depth and tilt, respectively. Thermocline depth was likely much deeper compared to Pliocene‐to‐modern conditions. Furthermore, a 4‐point‐based distribution of isotherms (4DI index) was used as a metric of the evenness or unevenness of the isotherm distributions. The 4DI index considerably reduced at around the EAIE and other Mi‐events, reflecting the evenly distributed isotherms under a more glaciated Antarctica. : (1) = Analytical precisions are ±0.10‰ for δ¹⁸O and ±0.04‰ for δ¹³C, whereas blank indicates those are ±0.05‰ forδ¹⁸O and ±0.03‰ for δ¹³C. |
format |
Dataset |
author |
Matsui, Hiroki Nishi, Hiroshi Kuroyanagi, Azumi Hayashi, Hiroki Ikehara, Minoru Takashima, Reishi |
author_facet |
Matsui, Hiroki Nishi, Hiroshi Kuroyanagi, Azumi Hayashi, Hiroki Ikehara, Minoru Takashima, Reishi |
author_sort |
Matsui, Hiroki |
title |
δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
title_short |
δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
title_full |
δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
title_fullStr |
δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
title_full_unstemmed |
δ¹⁸O and δ¹³C record of Paragloborotalia siakensis and Dentoglobigerina venezuelana from IODP Hole 321-U1337A |
title_sort |
δ¹⁸o and δ¹³c record of paragloborotalia siakensis and dentoglobigerina venezuelana from iodp hole 321-u1337a |
publisher |
PANGAEA - Data Publisher for Earth & Environmental Science |
publishDate |
2020 |
url |
https://dx.doi.org/10.1594/pangaea.914391 https://doi.pangaea.de/10.1594/PANGAEA.914391 |
geographic |
Antarctic East Antarctic Ice Sheet Pacific |
geographic_facet |
Antarctic East Antarctic Ice Sheet Pacific |
genre |
Antarc* Antarctic Antarctica Ice Sheet |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet |
op_relation |
https://dx.doi.org/10.1002/2016pa003058 https://dx.doi.org/10.2204/iodp.proc.320321.209.2013 |
op_rights |
Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode CC-BY-4.0 |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1594/pangaea.914391 https://doi.org/10.1002/2016pa003058 https://doi.org/10.2204/iodp.proc.320321.209.2013 |
_version_ |
1766257791448645632 |