Yang, H, Zhang, P, Lu, H et al. (6 more authors) (2023) Magnetic properties of gas hydrate-bearing sediments and their association with iron geochemistry in the Sea of Marmara, Turkey. Chemical Geology, 620. 121339. ISSN 0009-2541
Abstract
The anaerobic oxidation of methane, a key geochemical process that is involved in the cycling of sulfate and iron (oxyhydr)oxides in marine sediments, results in the formation of iron sulfides. Although ferrimagnetic iron sulfides have been identified in seepage systems, the link between iron migration and sediment magnetic properties remains poorly understood. Here, we investigate two cores from the Sea of Marmara to evaluate biogeochemical iron cycling and iron sulfide mineralogy in gas hydrate-bearing sediments. Magnetic analyses indicate the presence of greigite and pyrrhotite in a core from a hydrate-rich site with a high hydrocarbon flux, which contrasts with a lack of these minerals in a core characterized by only mild seepage. This is supported by the results of rock magnetic and scanning electron microscope analyses of the sediments. The presence of authigenic greigite is critical for assessing local redox records and together with the occurrence of monoclinic pyrrhotite may suggest specific diagenetic processes in gas hydrate environments. Our analysis demonstrates the usefulness of these ferrimagnetic minerals, with a high saturation isothermal remanent magnetization to magnetic susceptibility ratio (SIRM/χ > 15 kAm⁻¹) and a high index of hysteresis parameters (DJH > 0.2) indicative of magnetic mineralogy changes, for evaluating variability in the intensity of seepage fluxes and for estimating gas hydrate distributions.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2023 Published by Elsevier B.V. This is an author produced version of an article published in Chemical Geology. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Iron geochemistry; Magnetic properties; Sea of Marmara; Seepage activity; Gas hydrate; Sediments |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 24 Jan 2023 14:31 |
Last Modified: | 21 Jan 2024 01:13 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.chemgeo.2023.121339 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:195486 |
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