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Updated: Aug 7, 2026
09:45
Laboratory Simulation of an Iron(II)-rich Precambrian Marine Upwelling System to Explore the Growth of Photosynthetic Bacteria
Published on: July 24, 2016
The evolution of the Earth's surface iron cycle
Florian Scholz1, Sebastian Doetterl2, Dalton S Hardisty3
1Department of Earth System Sciences, University of Hamburg, Hamburg 20146, Germany.
Summary
Reactive iron (Fe) cycling in marine sediments significantly impacts Earth's atmosphere and oceans. This study reveals that continental weathering and tectonic erosion, not just redox changes, control Fe burial, influencing oxygen levels over geological time.
Area of Science:
- Geochemistry
- Paleoclimatology
- Marine Geology
Background:
- Pyrite formation in marine sediments controls atmospheric oxygen and seawater chemistry.
- The evolution of reactive iron (Fe) oxide precursors is poorly understood.
- Sedimentary reactive Fe variability is often attributed solely to redox changes.
Purpose of the Study:
- To differentiate redox influences from other factors controlling sedimentary reactive Fe.
- To investigate the long-term evolution of reactive Fe burial throughout Earth history.
- To link Fe cycling to continental weathering, erosion, and atmospheric oxygenation.
Main Methods:
- Developed a novel approach to distinguish redox-driven Fe influences.
- Analyzed a compilation of sedimentary reactive Fe data spanning 1,200 million years.
- Compared Fe data with proxies for continental weathering and land-ocean fluxes.
Main Results:
- Reactive Fe proportions were low from the Mesoproterozoic to Cambrian, rising in the mid- to late Paleozoic, and declining in the late Cenozoic.
- This pattern deviates from a purely redox-driven model.
- A strong coupling exists between Fe burial, oxidative silicate weathering, and tectonic erosion.
Conclusions:
- The temporal pattern of reactive Fe burial is linked to continental weathering and erosion.
- The mid- to late Paleozoic rise in Fe coincided with land plant proliferation and rising oxygen.
- A positive feedback loop likely amplified and was amplified by oxygenation through Fe cycling.
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