دورية أكاديمية
The Fate of Sedimentary Reactive Iron at the Land‐Ocean Interface: A Case Study From the Amazon Shelf
| العنوان: | The Fate of Sedimentary Reactive Iron at the Land‐Ocean Interface: A Case Study From the Amazon Shelf |
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| المؤلفون: | Paul Vosteen, Timo Spiegel, Martha Gledhill, Martin Frank, Matthias Zabel, Florian Scholz |
| المصدر: | Geochemistry, Geophysics, Geosystems, Vol 23, Iss 11, Pp n/a-n/a (2022) |
| بيانات النشر: | Wiley, 2022. |
| سنة النشر: | 2022 |
| المجموعة: | LCC:Geophysics. Cosmic physics LCC:Geology |
| مصطلحات موضوعية: | Geophysics. Cosmic physics, QC801-809, Geology, QE1-996.5 |
| الوصف: | Abstract Reactive iron (Fe) oxides in marine sediments may represent a source of bioavailable Fe to the ocean via reductive dissolution and sedimentary Fe release or can promote organic carbon preservation and long‐term burial. Furthermore, enrichments of reactive Fe (sum of Fe oxides, carbonates and sulfides normalized to total Fe) in ancient sediments are utilized as a paleo‐proxy for anoxic conditions. Considering the general importance of reactive Fe oxides in marine biogeochemistry, it is important to quantify their terrestrial sources and fate at the land‐ocean interface. We applied sequential Fe extractions to sediments from the Amazon shelf to investigate the transformation of river‐derived Fe oxides during early diagenesis. We found that ∼22% of the Amazon River‐derived Fe oxides are converted to Fe‐containing clay minerals in Amazon shelf sediments. The incorporation of reactive Fe into authigenic clay minerals (commonly referred to as reverse weathering) is substantiated by the relationship between Fe oxide loss and potassium (K) uptake from sedimentary pore waters, which is in agreement with the previously reported Fe/K stoichiometry of authigenic clay minerals. Mass balance calculations suggest that widely applied sequential extractions do not separate Fe‐rich authigenic clay minerals from reactive Fe oxides and carbonates. We conclude that the balance between terrestrial supply of reactive Fe and reverse weathering in continental margin sediments has to be taken into account in the interpretation of sedimentary Fe speciation data. |
| نوع الوثيقة: | article |
| وصف الملف: | electronic resource |
| اللغة: | English |
| تدمد: | 1525-2027 |
| Relation: | https://doaj.org/toc/1525-2027 |
| DOI: | 10.1029/2022GC010543 |
| URL الوصول: | https://doaj.org/article/ca484db77277429db66dbda2c15f1626 |
| رقم الأكسشن: | edsdoj.484db77277429db66dbda2c15f1626 |
| قاعدة البيانات: | Directory of Open Access Journals |
Full Text Finder | تدمد: | 15252027 |
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| DOI: | 10.1029/2022GC010543 |