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

TitleAn 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
Publication TypeJournal Article
Year of Publication2009
AuthorsKopp R.E, Schumann D., Raub T.D, Powars D.S, Godfrey L.V, Swanson-Hysell N.L, Maloof A.C, Vali H.
JournalPaleoceanography
Volume24
Issue4
Date Published2009/12/05
ISBN Number0883-8305
Other Numbers16Maloof
Keywordsmagnetofossils, Marlboro Clay, 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.

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URLhttps://doi.org/10.1029/2009PA001783
Short TitlePaleoceanography