A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites
This is the author accepted manuscript. Data availability: All shipboard generated data can be accessed through the IODP LIMS database (Weber 488 et al., 2021b; 2021c; 2021d; https://web.iodp.tamu.edu/LORE/). Magnetic data are available 489 through the MagIC database (Weber et al., 2019; Reilly et a...
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Online Access: | http://hdl.handle.net/10871/136582 |
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ftunivexeter:oai:ore.exeter.ac.uk:10871/136582 2024-09-15T18:34:03+00:00 A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites Reilly, BT Tauxe, L Brachfeld, SA Kenlee, B Gutjahr, M Dale, AW Hernández-Almeida, I Hemming, S Bailey, I Zheng, X Cheu, D Taglienti, R Weber, ME Raymo, ME Williams, T 2024 http://hdl.handle.net/10871/136582 en eng Wiley https://web.iodp.tamu.edu/LORE/ http://dx.doi.org/10.7288/V4/MAGIC/16842 https://doi.org/10.7288/V4/MAGIC/19778 https://doi.org/10.5281/zenodo.10035107 Geochemistry, Geophysics, Geosystems orcid:0000-0001-5150-5437 (Bailey, Ian) Awaiting citation and DOI 2302832 2114777 2114764 2114763 2114768 1450528 2245628 1326927 NE/T006609/1 NE/T013648/1 We2039/17-2 We2039/19-1 http://hdl.handle.net/10871/136582 1525-2027 2999-01-01 Under temporary indefinite embargo pending publication by Wiley. No embargo required on publication. AAM to be replaced with published version on publication http://www.rioxx.net/licenses/all-rights-reserved paleomagnetism Scotia Sea magnetic reversals Iceberg Alley geochemistry Matuyama-Brunhes Pirie Basin Dove Basin porewater International Ocean Discovery Porgram Article 2024 ftunivexeter https://doi.org/10.7288/V4/MAGIC/1684210.7288/V4/MAGIC/1977810.5281/zenodo.10035107 2024-07-09T23:39:59Z This is the author accepted manuscript. Data availability: All shipboard generated data can be accessed through the IODP LIMS database (Weber 488 et al., 2021b; 2021c; 2021d; https://web.iodp.tamu.edu/LORE/). Magnetic data are available 489 through the MagIC database (Weber et al., 2019; Reilly et al., 2024a). Additional data and rock 490 magnetic data files are available through the Zenodo database (Reilly et al., 2024b). We document an apparent downward displacement of the Matuyama-Brunhes magnetic reversal by ~20 meters at Scotia Sea International Ocean Discovery Program Site U1538 (Pirie Basin) by comparison with the well-defined paleomagnetic record at nearby Site U1537 (Dove Basin). Detailed stratigraphic correlation between the two sites is possible due to similar lithologic variations. However, the two sites have distinctly different porewater geochemistry. Notably, Site U1538 indicates a greater demand for electron acceptors to oxidize organic carbon and Fe2+ enrichment below the depth of SO42- depletion. Magnetic parameters indicate enrichment of an authigenic magnetic mineral with strong remanence properties around the depth of SO42- depletion (~46 meters at Site U1538) relative to magnetic parameters at correlative depths at Site U1537. Fe2+ enrichment below the depth of SO42- depletion is not predicted based on the energetically favorable order of electron acceptors for microbial respiration but is documented here and in other depositional settings. This indicates Fe2+ production exceeds the production of H2S by SO42- reduction, providing a geochemical environment that favors production and preservation of ferrimagnetic remanence-bearing iron sulfides over paramagnetic pyrite and, thus, a mechanism for deep chemical remanent magnetization acquisition at depths of tens of meters. The influence of authigenic ferrimagnetic iron sulfides on paleomagnetic signals can be difficult to demonstrate with magnetic properties alone, so this finding has implications for evaluating the fidelity of ... Article in Journal/Newspaper Scotia Sea University of Exeter: Open Research Exeter (ORE) |
institution |
Open Polar |
collection |
University of Exeter: Open Research Exeter (ORE) |
op_collection_id |
ftunivexeter |
language |
English |
topic |
paleomagnetism Scotia Sea magnetic reversals Iceberg Alley geochemistry Matuyama-Brunhes Pirie Basin Dove Basin porewater International Ocean Discovery Porgram |
spellingShingle |
paleomagnetism Scotia Sea magnetic reversals Iceberg Alley geochemistry Matuyama-Brunhes Pirie Basin Dove Basin porewater International Ocean Discovery Porgram Reilly, BT Tauxe, L Brachfeld, SA Kenlee, B Gutjahr, M Dale, AW Hernández-Almeida, I Hemming, S Bailey, I Zheng, X Cheu, D Taglienti, R Weber, ME Raymo, ME Williams, T A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
topic_facet |
paleomagnetism Scotia Sea magnetic reversals Iceberg Alley geochemistry Matuyama-Brunhes Pirie Basin Dove Basin porewater International Ocean Discovery Porgram |
description |
This is the author accepted manuscript. Data availability: All shipboard generated data can be accessed through the IODP LIMS database (Weber 488 et al., 2021b; 2021c; 2021d; https://web.iodp.tamu.edu/LORE/). Magnetic data are available 489 through the MagIC database (Weber et al., 2019; Reilly et al., 2024a). Additional data and rock 490 magnetic data files are available through the Zenodo database (Reilly et al., 2024b). We document an apparent downward displacement of the Matuyama-Brunhes magnetic reversal by ~20 meters at Scotia Sea International Ocean Discovery Program Site U1538 (Pirie Basin) by comparison with the well-defined paleomagnetic record at nearby Site U1537 (Dove Basin). Detailed stratigraphic correlation between the two sites is possible due to similar lithologic variations. However, the two sites have distinctly different porewater geochemistry. Notably, Site U1538 indicates a greater demand for electron acceptors to oxidize organic carbon and Fe2+ enrichment below the depth of SO42- depletion. Magnetic parameters indicate enrichment of an authigenic magnetic mineral with strong remanence properties around the depth of SO42- depletion (~46 meters at Site U1538) relative to magnetic parameters at correlative depths at Site U1537. Fe2+ enrichment below the depth of SO42- depletion is not predicted based on the energetically favorable order of electron acceptors for microbial respiration but is documented here and in other depositional settings. This indicates Fe2+ production exceeds the production of H2S by SO42- reduction, providing a geochemical environment that favors production and preservation of ferrimagnetic remanence-bearing iron sulfides over paramagnetic pyrite and, thus, a mechanism for deep chemical remanent magnetization acquisition at depths of tens of meters. The influence of authigenic ferrimagnetic iron sulfides on paleomagnetic signals can be difficult to demonstrate with magnetic properties alone, so this finding has implications for evaluating the fidelity of ... |
format |
Article in Journal/Newspaper |
author |
Reilly, BT Tauxe, L Brachfeld, SA Kenlee, B Gutjahr, M Dale, AW Hernández-Almeida, I Hemming, S Bailey, I Zheng, X Cheu, D Taglienti, R Weber, ME Raymo, ME Williams, T |
author_facet |
Reilly, BT Tauxe, L Brachfeld, SA Kenlee, B Gutjahr, M Dale, AW Hernández-Almeida, I Hemming, S Bailey, I Zheng, X Cheu, D Taglienti, R Weber, ME Raymo, ME Williams, T |
author_sort |
Reilly, BT |
title |
A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
title_short |
A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
title_full |
A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
title_fullStr |
A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
title_full_unstemmed |
A geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two Scotia Sea drill sites |
title_sort |
geochemical mechanism for >10 m apparent downward offsets of magnetic reversals inferred from comparison of two scotia sea drill sites |
publisher |
Wiley |
publishDate |
2024 |
url |
http://hdl.handle.net/10871/136582 |
genre |
Scotia Sea |
genre_facet |
Scotia Sea |
op_relation |
https://web.iodp.tamu.edu/LORE/ http://dx.doi.org/10.7288/V4/MAGIC/16842 https://doi.org/10.7288/V4/MAGIC/19778 https://doi.org/10.5281/zenodo.10035107 Geochemistry, Geophysics, Geosystems orcid:0000-0001-5150-5437 (Bailey, Ian) Awaiting citation and DOI 2302832 2114777 2114764 2114763 2114768 1450528 2245628 1326927 NE/T006609/1 NE/T013648/1 We2039/17-2 We2039/19-1 http://hdl.handle.net/10871/136582 1525-2027 |
op_rights |
2999-01-01 Under temporary indefinite embargo pending publication by Wiley. No embargo required on publication. AAM to be replaced with published version on publication http://www.rioxx.net/licenses/all-rights-reserved |
op_doi |
https://doi.org/10.7288/V4/MAGIC/1684210.7288/V4/MAGIC/1977810.5281/zenodo.10035107 |
_version_ |
1810475776629276672 |