Geology topics
Publications and source records attributed to Frederick Otto Simon.
Methods used by the U.S. Geological Survey for the sampling, comminution, and inorganic analysis of coal are summarized in this bulletin. Details, capabilities, and limitations of the methods are presented.
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A method is described for the determination of tungsten in geologic materials. After fusion with sodium peroxide, tungsten is isolated by extraction into chloroform with a-benzoinoxime, back extraction into aqueous potassium hydroxide, and precipitation with a-benzoinoxime. The activities of the 0.13 and 0.48 MeV gamma rays are measured. The activity of the 0.155 MeV gamma ray of 188 Re ( 188 W), added prior to the fusion, is measured to determine the yield; yields normally range from 40 to 90 percent. The coefficients of variation for less than part-per-million concentrations of tungsten are normally <20 percent; the limit of detection is 0.005 ppm for a 100-mg sample.
Minor element abundances were determined for galena and sphalerite from the Darwin mine, Inyo County, California. The temperature of deposition was calculated from the distribution coefficients determined experimentally by Bethke and Barton (1971) for cadmium and manganese in coexisting galena and sphalerite. The fractionation of cadmium between coexisting sphalerite and galena indicates a temperature of deposition of 416 degrees C+ or -20 degrees , the fractionation of manganese between the same mineral pair a temperature of 377 degrees C+ or -32 degrees . The fractionation of selenium gave unreasonably high temperatures. Three pairs gave temperatures between 568 degrees and 625 degrees C, the fourth pair a temperature of 889 degrees C. The reason for this descrepancy is not known.
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Rhenium is determined by spectrophotometry of the tellurium sol formed by the reduction of tellurate by stannous chloride under the catalytic influence of rhenium. A detailed investigation of the conditions for high sensitivity and stability at lowest concentration levels of rhenium is presented as well as the behavior of twenty-six ions. The method is applied to the determination of some tenths of a part per million or more of rhenium in a milligram aliquot of mineralized rocks, mixtures of molybdenite and rocks, and molybdenite concentrates. The practical quantity limit of detection is 2 x 10 -10 gram of rhenium. Samples are decomposed with a mixture of calcium oxide, calcium chloride, and magnesium oxide. On leaching, the constituents of the sample are precipitated either as calcium salts or as hydroxides except for rhenium and a small amount of molybdenum which pass into the filtrate. Residual molybdenum is removed extraction with 8-quinolinol in chloroform. Better than ninety-five percent recoveries are obtained with two fusions with flux.