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

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doi: 10.1029/2009PA001783
Author(s): Kopp, Robert E.; Schumann, Dirk; Raub, Timothy D.; Powars, David S.; Godfrey, Linda V.; Swanson-Hysell, Nicholas L.; Maloof, Adam C.; Vali, Hojatollah
Author Affiliation(s): Primary:
Princeton University, Department of Geosciences, Princeton, NJ, United States
McGill University, Canada
California Institute of Technology, United States
U. S. Geological Survey, United States
Rutgers State University of New Jersey, United States
Volume Title: Paleoceanography
Source: Paleoceanography, 24(4). Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 80 refs.; illus., incl. strat. cols., geol. sketch maps
Summary: 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.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Amazon River; Atlantic Coastal Plain; Atlantic Ocean; Carbon; Cenozoic; Facies; Ferromagnetic resonance spectra; Fluvial environment; Leg 150; Leg 174AX; Lithostratigraphy; Magnetite; Marine environment; Marlboro Clay; Maryland; New Jersey; North Atlantic; Ocean Drilling Program; Organic carbon; Oxides; Paleocene-Eocene Thermal Maximum; Paleoenvironment; Paleogene; Paleomagnetism; SEM data; Salisbury Embayment; Shelf environment; South America; Spectra; TEM data; Tertiary; United States; Virginia
Coordinates: N383645 N385755 W0721700 W0724905
N383000 N401500 W0740000 W0753500
Record ID: 2010081936
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