Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum

Dirk Schumann, Timothy David Raub, Robert E. Kopp, Jean-Luc Guerquin-Kern, Ting-Di Wu, Isabelle Rouiller, Aleksey V. Smirnov, S. Kelly Sears, Uwe Lucken, Sonia M. Tikoo, Reinhard Hesse, Joseph L. Kirschvink, Hojatollah Vali*

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    59 Citations (Scopus)

    Abstract

    We report the discovery of exceptionally large biogenic magnetite crystals in clay-rich sediments spanning the Paleocene-Eocene Thermal Maximum (PETM) in a borehole at Ancora, NJ. Aside from previously described abundant bacterial magnetofossils, electron microscopy reveals novel spearhead-like and spindle-like magnetite up to 4 mu m long and hexaoctahedral prisms up to 1.4 mu m long. Similar to magnetite produced by magnetotactic bacteria, these single-crystal particles exhibit chemical composition, lattice perfection, and oxygen isotopes consistent with an aquatic origin. Electron holography indicates single-domain magnetization despite their large crystal size. We suggest that the development of a thick suboxic zone with high iron bioavailability-a product of dramatic changes in weathering and sedimentation patterns driven by severe global warming-drove diversification of magnetite-forming organisms, likely including eukaryotes.

    Original languageEnglish
    Pages (from-to)17648-17653
    Number of pages6
    JournalProceedings of the National Academy of Sciences of the United States of America
    Volume105
    Issue number46
    DOIs
    Publication statusPublished - 18 Nov 2008

    Keywords

    • biomineralization
    • magnetofossil
    • SEDIMENT
    • OCEAN
    • CARBON-ISOTOPE EXCURSION
    • MAGNETOTACTIC BACTERIA
    • COMET IMPACT TRIGGER
    • PALAEOCENE/EOCENE BOUNDARY
    • GROWTH
    • PRODUCTIVITY
    • SHELF
    • MORPHOLOGY
    • electron microscopy

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