An Appalachian Amazon? Magnetofossil evidence for the development of a tropical river-like system in the mid-Atlantic United States during the Paleocene-Eocene thermal maximum
Abstract
On the mid-Atlantic Coastal Plain of the United States, Paleocene sands and silts are replaced during the Paleocene-Eocene Thermal Maximum (PETM) by the kaolinite-rich Marlboro Clay. The clay preserves abundant magnetite produced by magnetotactic bacteria and novel, presumptively eukaryotic, iron-biomineralizing microorganisms. Using ferromagnetic resonance spectroscopy and electron microscopy, we map the magnetofossil distribution in the context of stratigraphy and carbon isotope data and identify three magnetic facies in the clay: one characterized by a mix of detrital particles and magnetofossils, a second with a higher magnetofossil-to-detrital ratio, and a third with only transient magnetofossils. The distribution of these facies suggests that suboxic conditions promoting magnetofossil production and preservation occurred throughout inner middle neritic sediments of the Salisbury Embayment but extended only transiently to outer neritic sediments and the flanks of the embayment. Such a distribution is consistent with the development of a system resembling a modern tropical river-dominated shelf.
Additional Information
Received 18 April 2009; accepted 18 August 2009; published 5 December 2009. Acknowledgments. We thank Jerry Dickens, Neal Driscoll, Lucy Edwards, Mihaela Glamoclija, Dennis Kent, Ken Miller, and two anonymous reviewers for helpful comments and discussion. We thank Jim Browning for assistance sampling A, M, and SG and Ellen Thomas for access to samples of BR. New Jersey samples were provided by the Integrated Ocean Drilling Program (IODP). Maryland and Virginia samples were provided by the U.S. Geological Survey (USGS). Amazon samples were provided by Robert Aller. Research funding was provided in part by NASA Exobiology and Evolutionary Biology grant NNX07AK12G (to Joseph Kirschvink). REK was funded by a Princeton University Woodrow Wilson School Science, Technology, and Environmental Policy program postdoctoral fellowship. DS and HV were supported by grants from the Natural Science and Engineering Research Council (NSERC) of Canada and the Fonds québécois de la recherche sur la nature et les technologies (FQRNT) to the Centre for Biorecognition and Biosensors.Attached Files
Accepted Version - MarlboroBiogeomagnetism_2d_preprint_plus_auxiliary.pdf
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Additional details
- Eprint ID
- 16882
- Resolver ID
- CaltechAUTHORS:20091205-144532263
- NNX07AK12G
- NASA
- Princeton University
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Fonds québécois de la recherche sur la nature et les technologies (FQRNT)
- Centre for Biorecognition and Biosensors
- Created
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2009-12-18Created from EPrint's datestamp field
- Updated
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2021-11-08Created from EPrint's last_modified field