Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite
The deep ocean is generally considered to have changed from anoxic in the Precambrian to oxygenated by the Late Paleozoic (∼420–400 Ma) due to changes in atmospheric oxygen concentrations. When the transition occurred, that is, in the Early Paleozoic or not until the Late Paleozoic, is less well con...
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ftcaltechauth:oai:authors.library.caltech.edu:115024 2023-05-15T17:09:58+02:00 Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite Stolper, Daniel A. Pu, Xiaofei Lloyd, Max K. Christensen, Nikolas I. Bucholz, Claire E. Lange, Rebecca A. 2022-07 application/pdf application/vnd.ms-excel https://authors.library.caltech.edu/115024/ https://authors.library.caltech.edu/115024/6/Geochem%20Geophys%20Geosyst%20-%202022%20-%20Stolper%20-%20Constraints%20on%20Early%20Paleozoic%20Deep%E2%80%90Ocean%20Oxygen%20Concentrations%20From%20the%20Iron.pdf https://authors.library.caltech.edu/115024/2/2021gc010196-sup-0001-supporting%20information%20si-s01.pdf https://authors.library.caltech.edu/115024/3/2021gc010196-sup-0002-data%20set%20si-s01.xlsx https://authors.library.caltech.edu/115024/4/2021gc010196-sup-0003-data%20set%20si-s02.xlsx https://authors.library.caltech.edu/115024/5/2021gc010196-sup-0004-data%20set%20si-s03.xlsx https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000 en eng American Geophysical Union https://authors.library.caltech.edu/115024/6/Geochem%20Geophys%20Geosyst%20-%202022%20-%20Stolper%20-%20Constraints%20on%20Early%20Paleozoic%20Deep%E2%80%90Ocean%20Oxygen%20Concentrations%20From%20the%20Iron.pdf https://authors.library.caltech.edu/115024/2/2021gc010196-sup-0001-supporting%20information%20si-s01.pdf https://authors.library.caltech.edu/115024/3/2021gc010196-sup-0002-data%20set%20si-s01.xlsx https://authors.library.caltech.edu/115024/4/2021gc010196-sup-0003-data%20set%20si-s02.xlsx https://authors.library.caltech.edu/115024/5/2021gc010196-sup-0004-data%20set%20si-s03.xlsx Stolper, Daniel A. and Pu, Xiaofei and Lloyd, Max K. and Christensen, Nikolas I. and Bucholz, Claire E. and Lange, Rebecca A. (2022) Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite. Geochemistry, Geophysics, Geosystems, 23 (7). Art. No. e2021GC010196. ISSN 1525-2027. doi:10.1029/2021gc010196. https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000 <https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000> cc_by_nc CC-BY-NC Article PeerReviewed 2022 ftcaltechauth https://doi.org/10.1029/2021gc010196 2022-07-21T17:54:10Z The deep ocean is generally considered to have changed from anoxic in the Precambrian to oxygenated by the Late Paleozoic (∼420–400 Ma) due to changes in atmospheric oxygen concentrations. When the transition occurred, that is, in the Early Paleozoic or not until the Late Paleozoic, is less well constrained. To address this, we measured Fe³⁺/ΣFe of volcanic rocks, sheeted dykes, gabbros, and ultramafic rocks from the Early Paleozoic (∼485 Ma) Bay of Islands (BOI) ophiolite as a proxy for hydrothermal alteration in the presence or absence of O₂ derived from deep marine fluids. Combining this data with previously published data from the BOI indicates that volcanic rocks are oxidized relative to intrusive crustal rocks (0.35 ± 0.02 vs. 0.19 ± 0.01, 1 standard error), which we interpret to indicate that the volcanic section was altered by marine-derived fluids that contained some dissolved O₂. We compare our results directly to the Macquarie Island and Troodos ophiolites, drilled oceanic crust, previously compiled data for ophiolitic volcanic rocks, and newly compiled data for ophiolitic intrusive rocks. These comparisons show that the BOI volcanic (but not intrusive) rocks are oxidized relative to Precambrian equivalents, but are less oxidized relative to Late Paleozoic to modern equivalents. We interpret these results to indicate that the Early Paleozoic ocean contained dissolved O₂, but at concentrations ∼2.4× lower than for the Late Paleozoic to today. Article in Journal/Newspaper Macquarie Island Caltech Authors (California Institute of Technology) Geochemistry, Geophysics, Geosystems 23 7 |
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Caltech Authors (California Institute of Technology) |
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The deep ocean is generally considered to have changed from anoxic in the Precambrian to oxygenated by the Late Paleozoic (∼420–400 Ma) due to changes in atmospheric oxygen concentrations. When the transition occurred, that is, in the Early Paleozoic or not until the Late Paleozoic, is less well constrained. To address this, we measured Fe³⁺/ΣFe of volcanic rocks, sheeted dykes, gabbros, and ultramafic rocks from the Early Paleozoic (∼485 Ma) Bay of Islands (BOI) ophiolite as a proxy for hydrothermal alteration in the presence or absence of O₂ derived from deep marine fluids. Combining this data with previously published data from the BOI indicates that volcanic rocks are oxidized relative to intrusive crustal rocks (0.35 ± 0.02 vs. 0.19 ± 0.01, 1 standard error), which we interpret to indicate that the volcanic section was altered by marine-derived fluids that contained some dissolved O₂. We compare our results directly to the Macquarie Island and Troodos ophiolites, drilled oceanic crust, previously compiled data for ophiolitic volcanic rocks, and newly compiled data for ophiolitic intrusive rocks. These comparisons show that the BOI volcanic (but not intrusive) rocks are oxidized relative to Precambrian equivalents, but are less oxidized relative to Late Paleozoic to modern equivalents. We interpret these results to indicate that the Early Paleozoic ocean contained dissolved O₂, but at concentrations ∼2.4× lower than for the Late Paleozoic to today. |
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Article in Journal/Newspaper |
author |
Stolper, Daniel A. Pu, Xiaofei Lloyd, Max K. Christensen, Nikolas I. Bucholz, Claire E. Lange, Rebecca A. |
spellingShingle |
Stolper, Daniel A. Pu, Xiaofei Lloyd, Max K. Christensen, Nikolas I. Bucholz, Claire E. Lange, Rebecca A. Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
author_facet |
Stolper, Daniel A. Pu, Xiaofei Lloyd, Max K. Christensen, Nikolas I. Bucholz, Claire E. Lange, Rebecca A. |
author_sort |
Stolper, Daniel A. |
title |
Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
title_short |
Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
title_full |
Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
title_fullStr |
Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
title_full_unstemmed |
Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite |
title_sort |
constraints on early paleozoic deep-ocean oxygen concentrations from the iron geochemistry of the bay of islands ophiolite |
publisher |
American Geophysical Union |
publishDate |
2022 |
url |
https://authors.library.caltech.edu/115024/ https://authors.library.caltech.edu/115024/6/Geochem%20Geophys%20Geosyst%20-%202022%20-%20Stolper%20-%20Constraints%20on%20Early%20Paleozoic%20Deep%E2%80%90Ocean%20Oxygen%20Concentrations%20From%20the%20Iron.pdf https://authors.library.caltech.edu/115024/2/2021gc010196-sup-0001-supporting%20information%20si-s01.pdf https://authors.library.caltech.edu/115024/3/2021gc010196-sup-0002-data%20set%20si-s01.xlsx https://authors.library.caltech.edu/115024/4/2021gc010196-sup-0003-data%20set%20si-s02.xlsx https://authors.library.caltech.edu/115024/5/2021gc010196-sup-0004-data%20set%20si-s03.xlsx https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000 |
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Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
https://authors.library.caltech.edu/115024/6/Geochem%20Geophys%20Geosyst%20-%202022%20-%20Stolper%20-%20Constraints%20on%20Early%20Paleozoic%20Deep%E2%80%90Ocean%20Oxygen%20Concentrations%20From%20the%20Iron.pdf https://authors.library.caltech.edu/115024/2/2021gc010196-sup-0001-supporting%20information%20si-s01.pdf https://authors.library.caltech.edu/115024/3/2021gc010196-sup-0002-data%20set%20si-s01.xlsx https://authors.library.caltech.edu/115024/4/2021gc010196-sup-0003-data%20set%20si-s02.xlsx https://authors.library.caltech.edu/115024/5/2021gc010196-sup-0004-data%20set%20si-s03.xlsx Stolper, Daniel A. and Pu, Xiaofei and Lloyd, Max K. and Christensen, Nikolas I. and Bucholz, Claire E. and Lange, Rebecca A. (2022) Constraints on Early Paleozoic Deep-Ocean Oxygen Concentrations From the Iron Geochemistry of the Bay of Islands Ophiolite. Geochemistry, Geophysics, Geosystems, 23 (7). Art. No. e2021GC010196. ISSN 1525-2027. doi:10.1029/2021gc010196. https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000 <https://resolver.caltech.edu/CaltechAUTHORS:20220606-735977000> |
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cc_by_nc |
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CC-BY-NC |
op_doi |
https://doi.org/10.1029/2021gc010196 |
container_title |
Geochemistry, Geophysics, Geosystems |
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23 |
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7 |
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