USGS Open-File Report 02-125: Mineralogical characterization of strata of the Meade Peak phosphatic shale member of the Permian Phosphoria Formation; channel and individual rock samples of measured section J and their relationship to measured sections A and B, central part of Rasmussen Ridge, Caribou County, Idaho

Mineralogical characterization of strata of the Meade Peak phosphatic shale member of the Permian Phosphoria Formation; channel and individual rock samples of measured section J and their relationship to measured sections A and B, central part of Rasmussen Ridge, Caribou County, Idaho

By A. C. Knudsen, M. E. Gunter, J. R. Herring, and R. I. Grauch

Abstract

The Permian Phosphoria Formation of southeastern Idaho hosts one of the largest phosphate deposits in the world. Despite the economic significance of this Formation, the fine-grained nature of the phosphorite has discouraged detailed mineralogical characterization and quantification studies. Recently, selenium and other potentially toxic trace elements in mine wastes have drawn increased attention to this formation, and motivated additional study. This study uses powder X-ray diffraction (XRD), with Rietveld quantification software, to quantify and characterize the mineralogy of composite channel samples and individual samples collected from the stratigraphic sections measured by the U.S. Geological Survey in the Meade Peak Member of the Permian Phosphoria Formation at the Enoch Valley mine on Rasmussen Ridge, approximately 15 miles northeast of Soda Springs, Idaho.

First posted May 7, 2002

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For additional information, contact:
Geology, Minerals, Energy, and Geophysics Science Center
U.S. Geological Survey
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Suggested citation:

Knudsen, A. C., Gunter, M. E., Herring, J. R., Grauch, R. I, 2002, Mineralogical characterization of strata of the Meade Peak phosphatic shale member of the Permian Phosphoria Formation; channel and individual rock samples of measured section J and their relationship to measured sections A and B, central part of Rasmussen Ridge, Caribou County, Idaho: U.S. Geological Survey Open-File Report 02-125, 38 pp., https://pubs.usgs.gov/of/2002/0125/.

Contents

Abstract

Introduction

Methods

Results

References