Jena Johnson
University of Michigan, MI·Earth & Environmental Science
Most of Earth's iron ore comes from giant iron formations, iron-rich rocks that formed in ancient seawater before Earth's atmosphere held much oxygen and around the time life first appeared. How they formed, and whether living things helped, is still debated.
- Fields
Earth & Environmental Science
Chemistry
- Topics
iron formations
banded iron formation
Precambrian
- Grants
- 1 known grant, through Apr 2029
What they work on
- Precipitate the iron(II) silicate mineral greenalite at high pH in simulated ancient seawater and measure the resulting iron isotope fractionation and iron-to-manganese ratios.
- Test whether greenalite formation initiated by partial oxidation of Fe2+ to Fe3+ produces isotope and manganese fingerprints matching Precambrian iron formations.
- Simulate greenalite precipitation near seafloor hydrothermal vents with plume transport, and compare its chemical fingerprints against the other pathways and against iron formation rocks.
More about the research
Iron isotope data and manganese levels in the rocks seem to point to iron oxides as the original minerals, but high-resolution microscopy finds only iron silicate minerals as the first particles that formed from seawater. No one has directly measured the chemical fingerprints left behind when iron silicates form, which has left the debate stuck.
Why it matters
Explaining how iron formations arose could clarify how and where Earth's largest iron ore deposits formed. It could also reveal the chemistry of early oceans, whether life played a role in these deposits, and how oxygen rose in Earth's atmosphere, which is basic knowledge about the conditions under which life first developed.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
George Lazar
California State University-San Bernardino, CA·Earth & Environmental Science
Measure how the rare methane isotopologues 13CH3D and 12CH2D2 are distributed when organic matter decomposes under hydrothermal conditions, using lab experiments analyzed on the Panorama high-resolution mass spectrometer.
Eric Boyd
Montana State University, MT·Earth & Environmental Science
Conduct targeted experiments with microorganisms that oxidize pyrite at near-neutral pH to separate the individual steps of microbial pyrite oxidation.
Clara Blattler
University of Chicago, IL·Earth & Environmental Science·Early-career
Test hypotheses about the size and meaning of the Great Oxidation Event and the Lomagundi-Jatuli Event, using Paleoproterozoic carbonate rocks drilled in Fennoscandia in 2007.
The school
University of Michigan: 124 labs on PI Pages, $2.1B a year on research, 963 research doctorates a year.
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