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Page 6490, results 162226 - 162250

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Landscape esthetics: How to quantify the scenics of a river valley
Luna Bergere Leopold
1969, Natural History 37-44
There are an increasing number of bills before Congress that in one way or another affect the landscape or the environment. Each of these requires seemingly endless numbers of congressional hearings, which are recorded upon endless reams of paper.And if, for some reason, you happen to read the voluminous testimony...
Selective feeding by juvenile diving ducks in summer
James C. Bartonek, J.J. Hickey
1969, The Auk (86) 443-457
Waterfowl often fail to use foods that seem plentiful to the investigator. The extent to which selective feeding or rejection of foods is a function of behavioral and morphological adaptations of the species, conditioned behavior of the individual, or individual preference for certain foods has not been appraised. The objectives...
Pecoraite, Ni6Si4O10(OH)8, nickel analog of clinochrysotile, formed in the wolf creek meteorite
G. T. Faust, J. J. Fahey, B. Mason, E.J. Dwornik
1969, Science (165) 59-60
Pecoraite is a new phase in the natural system H2O-NiO-MgO- SiO2, the nickel analog of clinochrysotile. It occurs in cracks in the Wolf Creek meteorite in Australia where it was formed under hydrothermal conditions. Particles of pecoraite are very small curved plates which have begun to coil; some have achieved...
The relationship of the rare-earth composition of minerals to geological environment
M. Fleischer, Z. S. Altschuler
1969, Geochimica et Cosmochimica Acta (33) 725-732
It has been known for a long time that the composition of the lanthanides in minerals is controlled to a large degree by crystallo-chemical factors, but is also greatly influenced by changes in geological environment. In general, igneous rocks rich in silica are favourable for the concentration of the heavy...
Pyrolysis of humic and fulvic acids
R.L. Wershaw, G.E. Bohner Jr.
1969, Geochimica et Cosmochimica Acta (33) 757-762
Pyrolysis of humic and fulvic acids isolated from a North Carolina soil yields a variety of aromatic, heterocyclic and straight chain organ compounds. The pyrolysis products identified by gas chromatography and mass spectrometry indicate that humic and fulvic acids have aromatic and polysaccharide...
Uranium, thorium, and lead systematics in Granite Mountains, Wyoming
J.N. Rosholt, A.J. Bartel
1969, Earth and Planetary Science Letters (7) 141-147
Uranium, thorium and lead concentrations and isotopic compositions were determined on total rocks and a feldspar sample from widely separated parts of the Granite Mountains in central Wyoming. Linear relations defined by206Pb/204Pb −207Pb/204Pb and208Pb/204Pb −232Th/204Pb for the total rock samples define 2.8...
Interstitial brines in playa sediments
B.F. Jones, A. S. Van Denburgh, A.H. Truesdell, S.L. Rettig
1969, Chemical Geology (4) 253-262
Study of several closed drainages in the Great Basin has shown that the interstitial solutions of shallow, fine-grained playa deposits store a large quantity of dissolved solids and are often more concentrated than associated lakes and ponds, except in peripheral zones of stream or ground-water inflow. These interstitial fluids,...
Atomic-absorption determination of rhodium in chromite concentrates
M. M. Schnepfe, F. S. Grimaldi
1969, Talanta (16) 1461-1465
Rhodium is determined in chromite concentrates by atomic absorption after concentration either by co-precipitation with tellurium formed by the reduction of tellurite with tin(II) chloride or by fire assay into a gold bead. Interelement interferences in the atomic-absorption determination are removed by buffering the solutions with...
Loss of uranium from crystallized silicic volcanic rocks
J.N. Rosholt, D. C. Noble
1969, Earth and Planetary Science Letters (6) 268-270
Dense primarily crystallized silicic groundmass material from two welded ash-flow units and one lava flow of Tertiary age from the Western United States contain only 20 to 60 percent of the uranium present in nonhydrated glass from the rock units. These differences reflect...
A paleomagnetic study of secular variation in New Zealand
A. Cox
1969, Earth and Planetary Science Letters (6) 257-267
Ancient secular variation in New Zealand was determined from paleomagnetic measurements on 22 volcanic formations with ages of less than 0.68 m.y. The angular standard deviation from the field of an axial dipole is 13.2° with 95% confidence limits between 10.9° and 16.7°....
Magnetic susceptibility and exchange coupling in the mineral ardennite
A. N. Thorpe, F. E. Senftle, G. Donnay
1969, Journal of Physics and Chemistry of Solids (30) 2235-2239
Ardennite, a rare silicate mineral, contains about 19 wt.% manganese. Some of the manganese atoms are in positions which are close enough to allow negative exchange and hence a reduction of the total magnetic susceptibility. It is shown that the susceptibility can be accounted for approximately by the treatment of...
Oxygen isotope fractionation in divalent metal carbonates
J. R. O’Neil, R.N. Clayton, T.K. Mayeda
1969, Journal of Chemical Physics (51) 5547-5558
Equilibrium fractionation factors for the distribution of 18O between alkaline‐earth carbonates and water have been measured over the temperature range 0–500°C. The fractionation factors α">αα can be represented by the equations<span id="MathJax-Element-2-Frame"...
A purple-colored 1M mica clay from Silverton, Colorado
Pei-Lin Tien
1969, Clays and Clay Minerals (17) 245-249
A purple-colored clay of 1M mica polymorph in association with lead-zinc ore was collected from an abandoned mine dump near Silverton, Colorado. Electron micrographs show that the crystallites of the clay are less than 2µ in size and have poorly developed hexagonal outlines. Differential thermal and i.r. absorption analyses indicate...
Earthquake prediction and control
L. C. Pakiser, J. P. Eaton, J. H. Healy, C.B. Raleigh
1969, Science (166) 1467-1474
Scientists look beyond prediction to controlled release of stored strain energy in active fault zones....
Determination of traces of silver in waters by anion exchange and atomic absorption spectrophotometry
T. T. Chao, M. J. Fishman, J.W. Ball
1969, Analytica Chimica Acta (47) 189-195
A method has been developed for the accurate determination of 0.1–1 μg of silver per liter of water. The method permits stabilization of silver in water without loss to container walls. Optimum conditions have been established for the complete recovery of silver from water with an anion-exchange column, for quantitative...
The determination of nanogram amounts of Chromium in urine by x-ray fluorescence spectroscopy
K. Beyermann, H. J. Rose Jr., R.P. Christian
1969, Analytica Chimica Acta (45) 51-55
Nanogram amounts of chromium can be extracted as oxinate into chloform. By treatment of the chloroform layer 3 M hydrochloric acid, oxinates of other elements and excess of reagent are removed, leaving a chloroform solution of the chromium chelate only. This solution is concentrated and transferred to...
Saline water in southeastern New Mexico
W. L. Hiss, J.B. Peterson, T.R. Ramsey
1969, Chemical Geology (4) 341-360
Saline waters from formations of several geologic ages are being studied in a seven-county area in southeastern New Mexico and western Texas, where more than 30,000 oil and gas tests have been drilled in the past 40 years. This area of 7,500 sq. miles, which is stratigraphically complex, includes...