Mickey E. Gunter James R. Herring Andrew C. Knudsen 2001 This study used powder X-ray diffraction, with Rietveld quantification software to quantify and characterize the mineralogy of the 83 samples collected from two stratigraphic sections measured by the U.S. Geological Survey at the Dry Valley mine in the Meade Peak Member of the Phosphoria Formation. Analyses show extensive variability of carbonate substitution in the fluorapatite structure, determined by measuring the apatite a-cell dimension, as well as patterns of correlation between mineralogy and the stratigraphy. application/pdf 10.3133/ofr0172 en U.S. Geological Survey Preliminary mineralogical characterization of weathered and less-weathered strata of the Meade Peak phosphatic shale member of the Permian Phosphoria Formation: Measured sections C and D, Dry Valley, Caribou County, Idaho reports