Proxies for paleo-oxygenation: a downcore comparison between benthic foraminiferal surface porosity and I/Ca
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| Main Authors: | , , , , , , , , |
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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
2020
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| _version_ | 1867170099402637312 |
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| author | Lu, Wanyi Barbosa, Catia F Rathburn, Anthony E Xavier, Priscila da Matta Cruz, Anna P S Thomas, Ellen Rickaby, Rosalind E M Zhang, Yi Ge Lu, Zunli |
| author_facet | Lu, Wanyi Barbosa, Catia F Rathburn, Anthony E Xavier, Priscila da Matta Cruz, Anna P S Thomas, Ellen Rickaby, Rosalind E M Zhang, Yi Ge Lu, Zunli |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Benthic foraminiferal surface porosity (the mean percentage of surface area covered by pores; higher porosity: lower oxygenation) and iodine to calcium ratio (I/Ca, higher I/Ca: higher oxygenation) are both promising paleoceanographic proxies that will advance through testing in down-core studies. Here we report the first down-core comparison (~45 kyr) of these proxies for a core from the southern Brazilian margin (26°40.22′ S, 46°26.46′ W, 475 m water depth). Both proxies are most sensitive to low-O~2~ conditions (< 50 µmol/kg), and not well-constrained at higher O~2~ concentrations. Porosity values are generally low (< 15%) and I/Ca ranges between ~4 and ~6 µmol/mol throughout the core. The two proxies are overall consistent, suggesting that bottom-water oxygen concentrations at the site remained above 50 µmol/kg during the last 45 kyr. Several non-O~2~ factors (e.g., iodate reduction rates, water mass mixing, temperature, foraminiferal shell robustness) could influence the proxies and require further investigation. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_914577 |
| institution | PANGAEA |
| language | en |
| publishDate | 2020 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Proxies for paleo-oxygenation: a downcore comparison between benthic foraminiferal surface porosity and I/Ca Lu, Wanyi Barbosa, Catia F Rathburn, Anthony E Xavier, Priscila da Matta Cruz, Anna P S Thomas, Ellen Rickaby, Rosalind E M Zhang, Yi Ge Lu, Zunli AGE; Cibicidoides pseudoungerianus; Cibicidoides pseudoungerianus, Iodine/Calcium ratio; Cibicidoides pseudoungerianus, Iodine/Calcium ratio, standard deviation; Cibicidoides pseudoungerianus, porosity; Cibicidoides pseudoungerianus, porosity, standard deviation; Cibicidoides wuellerstorfi; Cibicidoides wuellerstorfi, porosity; Cibicidoides wuellerstorfi, porosity, standard deviation; DEPTH, sediment/rock; GeoB6201-5; Glacial; Gravity corer (Kiel type); M46/2; Meteor (1986); Methane; Oxygen; SL; southern Brazilian margin Benthic foraminiferal surface porosity (the mean percentage of surface area covered by pores; higher porosity: lower oxygenation) and iodine to calcium ratio (I/Ca, higher I/Ca: higher oxygenation) are both promising paleoceanographic proxies that will advance through testing in down-core studies. Here we report the first down-core comparison (~45 kyr) of these proxies for a core from the southern Brazilian margin (26°40.22′ S, 46°26.46′ W, 475 m water depth). Both proxies are most sensitive to low-O~2~ conditions (< 50 µmol/kg), and not well-constrained at higher O~2~ concentrations. Porosity values are generally low (< 15%) and I/Ca ranges between ~4 and ~6 µmol/mol throughout the core. The two proxies are overall consistent, suggesting that bottom-water oxygen concentrations at the site remained above 50 µmol/kg during the last 45 kyr. Several non-O~2~ factors (e.g., iodate reduction rates, water mass mixing, temperature, foraminiferal shell robustness) could influence the proxies and require further investigation. |
| title | Proxies for paleo-oxygenation: a downcore comparison between benthic foraminiferal surface porosity and I/Ca |
| topic | AGE; Cibicidoides pseudoungerianus; Cibicidoides pseudoungerianus, Iodine/Calcium ratio; Cibicidoides pseudoungerianus, Iodine/Calcium ratio, standard deviation; Cibicidoides pseudoungerianus, porosity; Cibicidoides pseudoungerianus, porosity, standard deviation; Cibicidoides wuellerstorfi; Cibicidoides wuellerstorfi, porosity; Cibicidoides wuellerstorfi, porosity, standard deviation; DEPTH, sediment/rock; GeoB6201-5; Glacial; Gravity corer (Kiel type); M46/2; Meteor (1986); Methane; Oxygen; SL; southern Brazilian margin |
| url | https://doi.org/10.1594/PANGAEA.914577 |