Quantifying pyrite oxidation on continental shelves during the onset of Antarctic glaciation in the Eocene-Oligocene transition

Weiqi Yao; Stefan Markovic; Adina Paytan; Andrea M. Erhardt; Ulrich G. Wortmann

doi:10.1016/j.epsl.2021.117015

Quantifying pyrite oxidation on continental shelves during the onset of Antarctic glaciation in the Eocene-Oligocene transition

Weiqi Yao, Stefan Markovic, Adina Paytan, Andrea M. Erhardt, Ulrich G. Wortmann

Earth and Environmental Sciences

Research output: Contribution to journal › Article › peer-review

5 Scopus citations

Abstract

The Eocene-Oligocene transition (EOT) is characterized by a global cooling trend, falling sea levels, and the onset of Antarctic glaciation. Previous studies investigate the interactions and feedbacks between ocean circulation, weathering, and atmospheric CO₂ levels during this time. Here we explore the role of biogeochemical sulfur cycling, and report seawater sulfate isotope data across the EOT. Our data show that seawater sulfate δ³⁴S and δ¹⁸O_SO₄ values decline by 0.6‰ and 1.5‰, respectively, between 34.5 and 33 Ma. Quantitative modeling suggests that approximately 8,000 Gt of the sulfide previously stored in shelf sediments has been reoxidized and transferred to the marine sulfate pool. This reoxidation process proceeds through reactions similar to those associated with acid mine drainage, generating 24,500 Gt sulfuric acid. These numbers are of similar magnitude as those estimated for Pleistocene glaciations and must have affected marine pH and/or alkalinity.

Original language	English
Article number	117015
Journal	Earth and Planetary Science Letters
Volume	568
DOIs	https://doi.org/10.1016/j.epsl.2021.117015
State	Published - Aug 15 2021

Bibliographical note

Publisher Copyright:
© 2021 Elsevier B.V.

Funding

We thank H. Li for her support with isotope analyses. This work was supported by a Discovery Grant of the Natural Sciences and Engineering Research Council of Canada (NSERC) grant RGPIN-2018-05873 to U.G.W. and the National Science Foundation (NSF) CAREER grant OCE-0449732 to A.P.

Funders	Funder number
National Science Foundation Arctic Social Science Program	OCE-0449732
Natural Sciences and Engineering Research Council of Canada	RGPIN-2018-05873

Keywords

Eocene-Oligocene transition
oxygen isotopes
pyrite oxidation
sulfate
sulfur isotopes

ASJC Scopus subject areas

Geophysics
Geochemistry and Petrology
Earth and Planetary Sciences (miscellaneous)
Space and Planetary Science

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

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10.1016/j.epsl.2021.117015

Cite this

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title = "Quantifying pyrite oxidation on continental shelves during the onset of Antarctic glaciation in the Eocene-Oligocene transition",

abstract = "The Eocene-Oligocene transition (EOT) is characterized by a global cooling trend, falling sea levels, and the onset of Antarctic glaciation. Previous studies investigate the interactions and feedbacks between ocean circulation, weathering, and atmospheric CO2 levels during this time. Here we explore the role of biogeochemical sulfur cycling, and report seawater sulfate isotope data across the EOT. Our data show that seawater sulfate δ34S and δ18OSO4 values decline by 0.6‰ and 1.5‰, respectively, between 34.5 and 33 Ma. Quantitative modeling suggests that approximately 8,000 Gt of the sulfide previously stored in shelf sediments has been reoxidized and transferred to the marine sulfate pool. This reoxidation process proceeds through reactions similar to those associated with acid mine drainage, generating 24,500 Gt sulfuric acid. These numbers are of similar magnitude as those estimated for Pleistocene glaciations and must have affected marine pH and/or alkalinity.",

keywords = "Eocene-Oligocene transition, oxygen isotopes, pyrite oxidation, sulfate, sulfur isotopes",

author = "Weiqi Yao and Stefan Markovic and Adina Paytan and Erhardt, {Andrea M.} and Wortmann, {Ulrich G.}",

note = "Publisher Copyright: {\textcopyright} 2021 Elsevier B.V.",

year = "2021",

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day = "15",

doi = "10.1016/j.epsl.2021.117015",

language = "English",

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AU - Yao, Weiqi

AU - Markovic, Stefan

AU - Paytan, Adina

AU - Erhardt, Andrea M.

AU - Wortmann, Ulrich G.

PY - 2021/8/15

Y1 - 2021/8/15

N2 - The Eocene-Oligocene transition (EOT) is characterized by a global cooling trend, falling sea levels, and the onset of Antarctic glaciation. Previous studies investigate the interactions and feedbacks between ocean circulation, weathering, and atmospheric CO2 levels during this time. Here we explore the role of biogeochemical sulfur cycling, and report seawater sulfate isotope data across the EOT. Our data show that seawater sulfate δ34S and δ18OSO4 values decline by 0.6‰ and 1.5‰, respectively, between 34.5 and 33 Ma. Quantitative modeling suggests that approximately 8,000 Gt of the sulfide previously stored in shelf sediments has been reoxidized and transferred to the marine sulfate pool. This reoxidation process proceeds through reactions similar to those associated with acid mine drainage, generating 24,500 Gt sulfuric acid. These numbers are of similar magnitude as those estimated for Pleistocene glaciations and must have affected marine pH and/or alkalinity.

AB - The Eocene-Oligocene transition (EOT) is characterized by a global cooling trend, falling sea levels, and the onset of Antarctic glaciation. Previous studies investigate the interactions and feedbacks between ocean circulation, weathering, and atmospheric CO2 levels during this time. Here we explore the role of biogeochemical sulfur cycling, and report seawater sulfate isotope data across the EOT. Our data show that seawater sulfate δ34S and δ18OSO4 values decline by 0.6‰ and 1.5‰, respectively, between 34.5 and 33 Ma. Quantitative modeling suggests that approximately 8,000 Gt of the sulfide previously stored in shelf sediments has been reoxidized and transferred to the marine sulfate pool. This reoxidation process proceeds through reactions similar to those associated with acid mine drainage, generating 24,500 Gt sulfuric acid. These numbers are of similar magnitude as those estimated for Pleistocene glaciations and must have affected marine pH and/or alkalinity.

KW - Eocene-Oligocene transition

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KW - sulfur isotopes

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Quantifying pyrite oxidation on continental shelves during the onset of Antarctic glaciation in the Eocene-Oligocene transition

Abstract

Bibliographical note

Funding

Keywords

ASJC Scopus subject areas

UN SDGs

Access to Document

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