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Anoxic photochemical weathering of pyrite on Archean continents

Citation

Hao, J and Liu, W and Goff, JL and Steadman, JA and Large, RR and Falkowski, PG and Yee, N, Anoxic photochemical weathering of pyrite on Archean continents, Science Advances, 8, (26) Article eabn2226. ISSN 2375-2548 (2022) [Refereed Article]


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Copyright Statement

2022 The Authors. some rights reserved; exclusive licensee American Association for the Advancement of Science. Distributed under the terms of of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, (https://creativecommons.org/licenses/by/4.0/)

DOI: doi:10.1126/sciadv.abn2226

Abstract

Sulfur is an essential element of life that is assimilated by Earth's biosphere through the chemical breakdown of pyrite. On the early Earth, pyrite weathering by atmospheric oxygen was severely limited, and low marine sulfate concentrations persisted for much of the Archean eon. Here, we show an anoxic photochemical mechanism of pyrite weathering that could have provided substantial amounts of sulfate to the oceans as continents formed in the late Archean. Pyrite grains suspended in anoxic ferrous iron solutions produced millimolar sulfate concentrations when irradiated with ultraviolet light. The Fe2+(aq) was photooxidized, which, in turn, led to the chemical oxidation of pyritic sulfur. Additional experiments conducted with 2.68 Ga shale demonstrated that photochemically derived ferric iron oxidizes and dissolves sedimentary pyrite during chemical weathering. The results suggest that before the rise of atmospheric oxygen, oxidative pyrite weathering on Archean continents was controlled by the exposure of land to sunlight.

Item Details

Item Type:Refereed Article
Keywords:pyrite; Archean; anoxia; photochemical; sulfate
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Geochemistry not elsewhere classified
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Steadman, JA (Mr Jeffrey Steadman)
UTAS Author:Large, RR (Professor Ross Large)
ID Code:153042
Year Published:2022
Web of Science® Times Cited:1
Deposited By:TIA - Research Institute
Deposited On:2022-09-02
Last Modified:2022-11-18
Downloads:3 View Download Statistics

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