Ciscato, ER, Bontognali, TRR, Poulton, SW orcid.org/0000-0001-7621-189X et al. (1 more author) (2019) Copper and its isotopes in organic-rich sediments: from the modern Peru Margin to Archean shales. Geosciences, 9 (8). 325. ISSN 2076-3263
Abstract
The cycling of copper (Cu) and its isotopes in the modern ocean is controlled by the interplay of biology, redox settings, and organic complexation. To help build a robust understanding of Cu cycling in the modern ocean and investigate the potential processes controlling its behavior in the geological past, this study presents Cu abundance and isotope data from modern Peru Margin sediments as well as from a suite of ancient, mostly organic-rich, shales. Analyses of an organic-pyrite fraction extracted from bulk modern sediments suggest that sulphidation is the main control on authigenic Cu enrichments in this setting. This organic-pyrite fraction contains, in most cases, >50% of the bulk Cu reservoir. This is in contrast to ancient samples, for which a hydrogen fluoride (HF)-dissolvable fraction dominates the total Cu reservoir. With <20% of Cu found in the organic-pyrite fraction of most ancient sediments, interpretation of the associated Cu isotope composition is challenging, as primary signatures may be masked by secondary processes. But the Cu isotope composition of the organic-pyrite fraction in ancient sediments hints at the potential importance of a significant Cu(I) reservoir in ancient seawater, perhaps suggesting that the ancient ocean was characterized by different redox conditions and a different Cu isotope composition to that of the modern ocean.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
Keywords: | copper; copper isotopes; organic-rich sediments; authigenic enrichment; sulphidation |
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 Jul 2019 12:39 |
Last Modified: | 25 Jun 2023 21:55 |
Status: | Published |
Publisher: | MDPI |
Identification Number: | 10.3390/geosciences9080325 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:148880 |