Project description
Round and round it goes: mineral oxidation and the Earth's redox cycle
Characterising the flux of carbon dioxide (CO2) and oxygen (O2) in our atmosphere and bodies of water over short and long time scales is vital to understanding the evolution of our planet, its climate and life forms on it. The cycles of these are tied to many different sources and sinks, among the least understood being oxidative weathering of sulphide minerals such as pyrite. Oxidative weathering of sulphides both removes O2 from the atmosphere and acts as a source of CO2. The EU-funded RESpiReS project is characterising this flux now and in our distant past and will also let us know if we can use it as a proxy for atmospheric compositions of O2 and CO2 over time. The resulting models of pyrite oxidation flux and atmospheric fluxes will fill important gaps in our current knowledge of global redox cycles.
Objective
To comprehensively reconstruct the evolution of Earth's climate, atmospheric and seawater chemical compositions, and conditions that favor the proliferation of life, it is critical to constrain all atmospheric carbon dioxide (CO2) and oxygen (O2) sources and sinks—including their dependencies on underlying environmental and geologic drivers. One major CO2 source and O2 sink remains poorly understood: oxidative weathering of sulfide minerals (e.g. pyrite) on land. In addition to driving Earth's atmospheric composition, pyrite oxidation potentially provides a quantitative proxy for recording past O2 and CO2 levels: the triple-oxygen isotope composition of sulfate. Still, three key questions remain unanswered: (i) what sets the modern-day pyrite oxidation flux, (ii) how has this flux changed over million- to hundred-million-year timescales, and (iii) do geologically preserved sulfate isotopes faithfully record past atmospheric conditions?
Here, I outline a multifaceted research program to answer these questions. This research will develop and apply novel experiments and state-of-the-art geochemical tracers to mechanistically understand pyrite oxidation and resulting sulfate isotope signatures. These results will inform theoretical, kinetic, and numerical models to quantify pyrite oxidation fluxes and atmospheric compositions throughout Earth's history—this combination of techniques is uniquely afforded by my background and expertise. Specifically, this research will: (i) constrain the electrochemical mechanism of pyrite oxidation and its isotopic consequences, (ii) assess which environmental and geologic controlling factors govern pyrite oxidation rates and fluxes, and (iii) determine how secondary redox cycling in the environment overprints sulfate isotope signatures.
An ERC Starting Grant will enable me to access the outstanding human resources and scientific infrastructure available at ETH Zürich in order to address this major open questions in modern geochemistry.
Fields of science (EuroSciVoc)
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
CORDIS classifies projects with EuroSciVoc, a multilingual taxonomy of fields of science, through a semi-automatic process based on NLP techniques.
- natural sciencesearth and related environmental sciencesgeochemistry
- humanitieshistory and archaeologyhistory
- natural scienceschemical scienceselectrochemistryelectrolysis
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Funding Scheme
ERC-STG - Starting GrantHost institution
8092 Zuerich
Switzerland