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

Robert E. Kopp, Dirk Schumann, Timothy D. Raub, David S. Powars, Linda V. Godfrey, Nicholas L. Swanson-Hysell, Adam C. Maloof, Hojatollah Vali

Research output: Contribution to journalArticlepeer-review

63 Scopus citations

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, ironbiomineralizing 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.

Original languageEnglish (US)
Article numberPA4211
JournalPaleoceanography
Volume24
Issue number4
DOIs
StatePublished - Oct 2009

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Palaeontology

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