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Page 6211, results 155251 - 155275

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Not all publications have extents, not all extents are completely accurate
The reproduction of lake trout in southern Lake Superior
Paul H. Eschmeyer
1955, Transactions of the American Fisheries Society (84) 47-74
The principal spawning grounds of lake trout (Salvelinus namaycush namaycush) in United States waters of southern Lake Superior are on rocky shoals at depths of less than 20 fathoms. Most spawning occurs in October and early November. Of the mature fish collected on or near the spawning grounds, 60...
The pygmy whitefish, Coregonus coulteri, in Lake Superior
Paul H. Eschmeyer, Reeve M. Bailey
1955, Transactions of the American Fisheries Society (84) 161-199
Bottom trawling by the U. S. Fish and Wildlife Service motor vessel Cisco in Lake Superior in 1952–1953 revealed a large population of a tiny whitefish, Coregonus (Prosopium) coulteri, which has been reported previously only from northwestern North America. The hiatus in range, from Lake Superior to the Columbia...
Internal standards in fluorescent X-ray spectroscopy
I. Adler, J. M. Axelrod
1955, Spectrochimica Acta (7) 91-99
The use of internal standards in the analysis of ores and minerals of widely-varying matrix by means of fluorescent X-ray spectroscopy is frequently the most practical approach. Internal standards correct for absorption and enhancement effects except when an absorption edge falls between the comparison lines or a very strong emission...
Radioactive equilibrium in ancient marine sediments
Irving A. Breger
1955, Geochimica et Cosmochimica Acta (8) 63-73
Radioactive equilibrium in eight marine sedimentary formations has been studied by means of direct determinations of uranium, radium and thorium. Alpha-particle counting has also been carried out in order to cross-calibrate thick-source counting techniques. The maximum deviation from radioactive equilibrium that has been noted is 11 per cent—indicating that there...
Composition and origin of basaltic magma of the Hawaiian Islands
H. A. Powers
1955, Geochimica et Cosmochimica Acta (7) 77-107
Silica-saturated basaltic magma is the source of the voluminous lava flows, erupted frequently and rapidly in the primitive shield-building stage of activity, that form the bulk of each Hawaiian volcano. This magma may be available in batches that differ slightly in free silica content from batch to batch both at...
Automatic photometric titrations of calcium and magnesium in carbonate rocks
Leonard Shapiro, W. W. Brannock
1955, Analytical Chemistry (27) 725-728
Rapid nonsubjective methods have been developed for the determination of calcium and magnesium in carbonate rocks. From a single solution of the sample, calcium is titrated directly, and magnesium is titrated after a rapid removal of R2O3 and precipitation of calcium as the tungstate. A concentrated and a dilute solution...
Molybdenum blue reaction and determination of phosphorus in waters containing arsenic, silicon, and germanium
H. Levine, J.J. Rowe, F. S. Grimaldi
1955, Analytical Chemistry (27) 258-262
Microgram amounts of phosphate are usually determined by the molybdenum blue reaction, but this reaction is not specific for phosphorus. The research established the range of conditions under which phosphate, arsenate, silicate, and germanate give the molybdenum blue reaction for differentiating these elements, and developed a method for the determination...
Determination of thorium and of rare earth elements in cerium earth minerals and ores
M. K. Carron, D. L. Skinner, R.E. Stevens
1955, Analytical Chemistry (27) 1058-1061
The conventional oxalate method for precipitating thorium and the rare earth elements in acid solution exhibits definite solubilities of these elements. The present work was undertaken to establish conditions overcoming these solubilities and to find optimum conditions for precipitating thorium and the rare earth elements as hydroxides and sebacates. The...
Determination of thorium by fluorescent x-ray spectrometry
I. Adler, J. M. Axelrod
1955, Analytical Chemistry (27) 1002-1003
A fluorescent x-ray spectrographic method for the determination of thoria in rock samples uses thallium as an internal standard. Measurements are made with a two-channel spectrometer equipped with quartz (d = 1.817 A.) analyzing crystals. Particle-size effects are minimized by grinding the sample components with a mixture of silicon carbide...
Theoretical effect of diffusion on isotopic abundance ratios in rocks and associated fluids
F. E. Senftle, J. T. Bracken
1955, Geochimica et Cosmochimica Acta (7) 61-76
Diffusion is considered as a possible process of isotope fractionation taking place throughout geologic time. Both diffusion in solids and diffusion in liquids are taken as possible mechanisms, the latter being more important. Arguments are presented to show that if significant fractionation takes place within a crystal by outward diffusion...
Germanium and uranium in coalified wood from upper Devonian black shale
Irving A. Breger, J.M. Schopf
1955, Geochimica et Cosmochimica Acta (7) 287-293
Microscopic study of black, vitreous, carbonaceous material occurring in the Chattanooga shale in Tennessee and in the Cleveland member of the Ohio shale in Ohio has revealed coalified woody plant tissue. Some samples have shown sufficient detail to be identified with the genus Cauixylon....
Determination of small and large amounts of fluorine in rocks
F. S. Grimaldi, B. Ingram, F. Cuttitta
1955, Analytical Chemistry (27) 918-921
Gelatinous silica and aluminum ions retard the distillation of fluorine in the Willard and Winter distillation method. A generally applicable, simple method for the determination of fluorine in rocks containing aluminum or silicon or both as major constituents was desired. In the procedure developed, the sample is fused with a...
Determination of boron in silicates after ion exchange separation
Henry Kramer
1955, Analytical Chemistry (27) 144-145
Existing methods for the determination of boron in silicates are not entirely satisfactory. Separation as the methyl ester is lengthy and frequently erratic. An accurate and rapid method applicable to glass, mineral, ore, and water samples uses ion exchange to remove interfering cations, and boron is determined titrimetrically in the...
Field determination of microgram quantities of niobium in rocks
F. N. Ward, A. P. Marranzino
1955, Analytical Chemistry (27) 1325-1328
A rapid, simple, and moderately accurate method was needed for the determination of traces of niobium in rocks. The method developed is based on the reaction of niobium(V) with thiocyanate ion in a 4M hydrochloric acid and 0.5M tartaric acid medium, after which the complex is extracted with ethyl ether....
Determination of total sulfur content of sedimentary rocks by a combustion method
M. E. Coller, R. K. Leininger
1955, Analytical Chemistry (27) 949-951
Total sulfur has been determined in common sedimentary rocks by a combustion method. Sulfur contents range from 0.001 to 5.0%. Experiments show that the combustion method can be used in analyzing sedimentary rocks in which sulfur is present as sulfide, sulfate, or both. Pulverized samples from 0.100 to 0.500 gram...