HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Rivers, J. M. Articles by Doll, W. E. Search for Related Content PubMed Articles by Rivers, J. M. Articles by Doll, W. E. GeoRef GeoRef Citation Agricola Articles by Rivers, J. M. Articles by Doll, W. E. Related Collections Redox Processes Remote Sensing Soil Physics

DIVISION S-9—SOIL MINERALOGY

Investigation into the Origin of Magnetic Soils on the Oak Ridge Reservation, Tennessee

^a Environmental Sciences Division, Oak Ridge National Lab., P.O. Box 2008, Oak Ridge, TN 37831-6038
^b Jr., Geology Dep., Temple Univ., 1901 N. 13th St., Beury Hall, Philadelphia, PA 19122-6081

^* Corresponding author (rivers{at}geoladm.geol.queensu.ca)

In 1993–1994, researchers at Oak Ridge National Laboratory collected high-resolution airborne geophysical data on the Oak Ridge Reservation, Oak Ridge, TN. The data were collected in part to address concerns about possible undocumented hazardous waste sites. Interpretation of the aeromagnetic data was complicated, however, by the discovery in remote areas of numerous small magnetic anomalies of natural origin. Magnetic susceptibility measurements of core showed that the underlying Copper Ridge Dolomite was non-magnetic. We attribute the magnetic anomalies to the presence of the ferromagnetic mineral maghemite (-Fe₂O₃), which formed during pedogenesis of Fe-enriched colluvium that had infilled low-lying areas, including dolines. We discuss explanations offered in the literature for the formation of magnetic soils, and present evidence based on profile descriptions, thin sections, x-ray diffraction (XRD), and scanning electron microscopy (SEM), that in this case, maghemite formed either by anaerobic microbial Fe reduction followed by the formation of single-domain maghemite, or by abiological weathering and reduction of an Fe-bearing mineral followed by oxidation. Naturally occurring magnetic soils may produce magnetic anomalies similar to those characteristics of anthropogenic objects, such as buried waste drums, and complicate interpretation of airborne geophysical surveys.

Abbreviations: EDX, energy dispersive x-ray analysis • ICPMS, inductively coupled plasma-mass spectrometry • ORNL, Oak Ridge National Laboratory • SEM, scanning electron microscopy • XRD, x-ray diffraction

This article has been cited by other articles:

				N. Perrier, R. J. Gilkes, and F. Colin HEATING Fe OXIDE-RICH SOILS INCREASES THE DISSOLUTION RATE OF METALS Clays and Clay Minerals, April 1, 2006; 54(2): 165 - 175. [Abstract] [Full Text] [PDF]