Journal article
Gigantism in unique biogenic magnetite at the Paleocene-Eocene Thermal Maximum
D Schumann, TD Raub, RE Kopp, JL Guerquin-Kern, TD Wu, I Rouiller, AV Smirnov, SK Sears, U Lücken, SM Tikoo, R Hesse, JL Kirschvink, H Vali
Proceedings of the National Academy of Sciences of the United States of America | NATL ACAD SCIENCES | Published : 2008
Open access
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..
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Funding Acknowledgements
We gratefully acknowledge comments from Boswell Wing, Adam Maloof, Nicholas Swanson-Hysell, and Harunur Rashid and technical assistance from Jeannie Mui. We are grateful to the editor and three anonymous reviewers for their constructive comments, which improved the final version of the manuscript. This work was supported by grants from the Natural Science and Engineering Research Council of Canada and the Fonds Quebecois de la Recherche Sur la Nature et les Technologies to the Centre for Biorecognition and Biosensors (H.V.) and the NASA Exobiology program (J.L.K.). Samples were provided by the Ocean Drilling Program, which is sponsored by the U.S. National Science Foundation and by participating countries under management of Joint Oceanographic Institutions, Inc.