Deep abiotic weathering of pyrite
Pyrite is a ubiquitous iron sulfide mineral that is oxidized by trace oxygen. The mineral has been largely absent from global sediments since the rise in oxygen concentration in Earth's early atmosphere. We analyzed weathering in shale, the most common rock exposed at Earth's surface, with...
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Published in | Science (American Association for the Advancement of Science) Vol. 370; no. 6515 |
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Main Authors | , , , |
Format | Journal Article |
Language | English |
Published |
United States
American Association for the Advancement of Science (AAAS)
23.10.2020
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Subjects | |
Online Access | Get full text |
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Summary: | Pyrite is a ubiquitous iron sulfide mineral that is oxidized by trace oxygen. The mineral has been largely absent from global sediments since the rise in oxygen concentration in Earth's early atmosphere. We analyzed weathering in shale, the most common rock exposed at Earth's surface, with chemical and microscopic analysis. By looking across scales from 10
to 10
meters, we determined the factors that control pyrite oxidation. Under the atmosphere today, pyrite oxidation is rate-limited by diffusion of oxygen to the grain surface and regulated by large-scale erosion and clast-scale fracturing. We determined that neither iron- nor sulfur-oxidizing microorganisms control global pyrite weathering fluxes despite their ability to catalyze the reaction. This multiscale picture emphasizes that fracturing and erosion are as important as atmospheric oxygen in limiting pyrite reactivity over Earth's history. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 USDOE National Science Foundation (NSF) OBES DE-FG02-05ER15675; FG02-05ER15675; EAR–1239285; EAR–1331726; EAR-1925903 USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division |
ISSN: | 0036-8075 1095-9203 |
DOI: | 10.1126/science.abb8092 |