Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies

Abstract Serpentinization, a consequence of water‐rock interaction in mafic and ultramafic rocks, refers to the hydrothermal alteration of olivine and pyroxene with serpentine as the typical product. Magnetite is produced in variable amounts during this serpentinization process. Here, we conducted a...

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Main Authors: Yuzhen Zhang, Zhaoxia Jiang, Kai Su, Mark J. Dekkers, Sanzhong Li, Qingsong Liu
Format: Article
Language:English
Published: Wiley 2025-02-01
Series:Geochemistry, Geophysics, Geosystems
Online Access:https://doi.org/10.1029/2024GC012035
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author Yuzhen Zhang
Zhaoxia Jiang
Kai Su
Mark J. Dekkers
Sanzhong Li
Qingsong Liu
author_facet Yuzhen Zhang
Zhaoxia Jiang
Kai Su
Mark J. Dekkers
Sanzhong Li
Qingsong Liu
author_sort Yuzhen Zhang
collection DOAJ
description Abstract Serpentinization, a consequence of water‐rock interaction in mafic and ultramafic rocks, refers to the hydrothermal alteration of olivine and pyroxene with serpentine as the typical product. Magnetite is produced in variable amounts during this serpentinization process. Here, we conducted a systematic rock magnetic study on the serpentinite of Ocean Drilling Program (ODP) Hole 1070A from the Iberia Abyssal Plain. From bottom to top, three units are distinguished rock‐magnetically: (a) serpentinized peridotite dominated by single‐domain (SD) ± multidomain (MD) magnetite particles; (b) gabbro with SD ± vortex state magnetite; (c) breccia dominated by MD ± vortex and SD ± vortex state maghemite/hematite and magnetite. Samples of the three units are highly serpentinized with serpentinization degrees >60%. The magnetite content increases exponentially with the degree of serpentinization. Two phases of serpentinization are proposed: (a) massive serpentinization that occurred before mantle exhumation and (b) maghemitization‐serpentinization that occurred near or at the seafloor after the final exhumation of mantle peridotites. The latter reduces the magnetization of the breccia unit significantly. Serpentinized peridotite associated with strong magnetization is the dominant contributor to the marine magnetic anomalies in ocean to continent transition areas.
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spelling doaj-art-5dc6e0bc549e4cffbdff6481b4bf2bbe2025-08-20T02:16:01ZengWileyGeochemistry, Geophysics, Geosystems1525-20272025-02-01262n/an/a10.1029/2024GC012035Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic AnomaliesYuzhen Zhang0Zhaoxia Jiang1Kai Su2Mark J. Dekkers3Sanzhong Li4Qingsong Liu5Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences Ocean University of China Qingdao ChinaFrontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences Ocean University of China Qingdao ChinaResearch Institute of Bohai Oil Field CNOOC Tianjin Branch Company Tianjin ChinaDepartment of Earth Sciences Faculty of Geosciences Utrecht University Utrecht The NetherlandsFrontiers Science Center for Deep Ocean Multispheres and Earth System, Key Lab of Submarine Geosciences and Prospecting Techniques, MOE, College of Marine Geosciences Ocean University of China Qingdao ChinaSouthern University of Science and Technology Shenzhen ChinaAbstract Serpentinization, a consequence of water‐rock interaction in mafic and ultramafic rocks, refers to the hydrothermal alteration of olivine and pyroxene with serpentine as the typical product. Magnetite is produced in variable amounts during this serpentinization process. Here, we conducted a systematic rock magnetic study on the serpentinite of Ocean Drilling Program (ODP) Hole 1070A from the Iberia Abyssal Plain. From bottom to top, three units are distinguished rock‐magnetically: (a) serpentinized peridotite dominated by single‐domain (SD) ± multidomain (MD) magnetite particles; (b) gabbro with SD ± vortex state magnetite; (c) breccia dominated by MD ± vortex and SD ± vortex state maghemite/hematite and magnetite. Samples of the three units are highly serpentinized with serpentinization degrees >60%. The magnetite content increases exponentially with the degree of serpentinization. Two phases of serpentinization are proposed: (a) massive serpentinization that occurred before mantle exhumation and (b) maghemitization‐serpentinization that occurred near or at the seafloor after the final exhumation of mantle peridotites. The latter reduces the magnetization of the breccia unit significantly. Serpentinized peridotite associated with strong magnetization is the dominant contributor to the marine magnetic anomalies in ocean to continent transition areas.https://doi.org/10.1029/2024GC012035
spellingShingle Yuzhen Zhang
Zhaoxia Jiang
Kai Su
Mark J. Dekkers
Sanzhong Li
Qingsong Liu
Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
Geochemistry, Geophysics, Geosystems
title Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
title_full Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
title_fullStr Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
title_full_unstemmed Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
title_short Magnetic Characteristics of Highly Serpentinized Peridotite in the Iberia Abyssal Plain and Implications for Marine Magnetic Anomalies
title_sort magnetic characteristics of highly serpentinized peridotite in the iberia abyssal plain and implications for marine magnetic anomalies
url https://doi.org/10.1029/2024GC012035
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