Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum
Document Type
Article
Publication Date
11-18-2008
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 μm long and hexaoctahedral prisms up to 1.4 μm 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. © 2008 by The National Academy of Sciences of the USA.
Publication Title
Proceedings of the National Academy of Sciences of the United States of America
Recommended Citation
Schumann, D.,
Raub, T.,
Kopp, R.,
Guerquin-Kern, J.,
Wu, T.,
Rouiller, I.,
Smirnov, A.,
Sears, S.,
Lücken, U.,
Tikoo, S.,
Hesse, R.,
Kirschvink, J.,
&
Vali, H.
(2008).
Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum.
Proceedings of the National Academy of Sciences of the United States of America,
105(46), 17648-17653.
http://doi.org/10.1073/pnas.0803634105
Retrieved from: https://digitalcommons.mtu.edu/michigantech-p/9034