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Page 6460, results 161476 - 161500

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Biotites from granitic rocks of the central Sierra Nevada batholith, California
F. C. W. Dodge, V. C. Smith, R. E. Mays
1969, Journal of Petrology (10) 250-271
Biotites from plutonic rocks of the central Sierra Nevada and Inyo Mountains, California, have been examined and characterized by powder X-ray diffraction and optical and chemical methods.Compositions of the biotites define a trend in the compositional triangle Fe+3 Fe+2Mg. When related to the experimentally studied ternary system KFe3+3AlSisO12H-1-KFe3+2...
Well logging with californium-252
W. Scott Keys, A. R. Boulogne
1969, Conference Paper, SPWLA 10th Annual Logging Symposium
Californium 252 is an isotopic neutron source that has only recently become available for experimental well logging. One curie of 252Cf emits 4.4 x 109 neutrons per second by spontaneous fission, 300 times the emission rate of any other one curie radioisotopic source. California 252 has several other advantages...
Technologic gaps in exploration and exploitation of sub-sea mineral resources
Frank F. Wang, Michael J. Cruickshank
1969, Conference Paper, Offshore technology conference
Progress in marine hard mineral exploration and exploitation has been severely restricted by technologic gaps and the lack of discovery of deposits that can be exploited at a competitive price in the world markets. Immediate needs include improved techniques of placer drilling to permit more reliable evaluation of in situ...
Wind training in some prairie trees
M.A. Bogan, T.R. Mollhagen
1969, Southwestern Naturalist (14) 134-136
Asymmetry in tree crowns has been established for some time. Lawrence (Ecol. Monogr. 9:217-257, 1939) studied wind training, one cause of asymmetry, in the Columbia River Gorge. He and Boyce (Ecol. Monogr. 24: 29-67, 1954) cite the intensity and direction of wind during the growing season as the...
Infrared scanning images: An archeological application
G. G. Schaber, G.J. Gumerman
1969, Science (164) 712-713
Aerial infrared scanner images of an area near the Little Colorado River in north-central Arizona disclosed the existence of scattered clusters of parallel linear features in the ashfall area of Sunset Crater. The features are not obvious in conventional aerial photographs, and only one cluster could be recognized on the...
High-pressure mechanical instability in rocks
J.D. Byerlee, W.F. Brace
1969, Science (164) 713-715
At a confining pressure of a few kilobars, deformation of many sedimentary rocks, altered mafic rocks, porous volcanic rocks, and sand is ductile, in that instabilities leading to audible elastic shocks are absent. At pressures of 7 to 10 kilobars, however, unstable faulting and stick-slip in certain of these rocks...
Taxonomy of the common dolphins of the eastern Pacific Ocean
Richard C. Banks, Robert L. Brownell Jr.
1969, Journal of Mammalogy (50) 262-271
Delphinus bairdii Dall is a species of dolphin distinct from D. delphis Linnaeus, with which it has usually been synonymized. D. bairdii has a longer rostrum relative to the zygomatic width of the skull; the ratio of these measurements falls at 1.55 or above for bairdii and 1.53 and below for delphis. In the eastern Pacific Ocean, D. bairdii is found...
Micromineralogy of silver-bearing sphalerite from Flat River, Missouri
Charles M. Taylor, Arthur S. Radtke
1969, Economic Geology (64) 306-318
Detailed mineralogical and chemical study of sphalerite-rich lead ores from Flat River, Mo., confirms the presence of anomalous amounts of silver in the sphalerite. Although silver is closely associated with chlorine and no silver sulfide minerals were identified, geochemical considerations indicate the silver may be...
A demographic analysis of continuously irradiated and nonirradiated populations of the lizard, Uta stansburiana
F.B. Turner, P.A. Medica, J.R. Lannom Jr., G.A. Hoddenbach
1969, Radiation Research (38) 349-356
A natural population of the lizard Uta stansburiana occupying a fenced 20-acre area in southern Nevada has been exposed to essentially continuous gamma irradiation since February 1964. Tissue doses averaged about 2 rads/day. Nonirradiated populations occupying three adjoining 20-acre areas have also been investigated. Five years of sampling data drawn...
Willamette Basin Comprehensive Study of Water and Related Land Resources: Appendix B--Hydrology
Willamette Basin Task Force
1969, Report, Willamette Basin comprehensive study of water and related land resources
The study was undertaken to plan for the proper development of water andrelated land resources of the Willamette Basin in Oregon. Appendix B, along with Appendices A and C, provides supporting data for the functional Appendices D through L. Climate is first discussed, including the climatic significance of geographical features such as the...
Cycads: Fossil evidence of late Paleozoic origin
S.H. Mamay
1969, Science (164) 295-296
Plant fossils from Lower Permian strata of the southwestern United States have been interpreted as cycadalean megasporophylls. They are evidently descended from spermopterid elements of the Pennsylvanian Taeniopteris complex; thus the known fossil history of the cycads is extended from the Late Triassic into the late Paleozoic. Possible implications...
Ellsworth Mountains: Position in West Antarctica due to sea-floor spreading
J. M. Schopf
1969, Science (164) 63-66
Similarities of middle and upper Paleozoic deposits of the Ellsworth Mountains with those of the Pensacola, Horlick, and other Transantarctic mountains indicate that all these ranges may have had a related geologic history. A tentative explanation is now suggested which involves sea-floor spreading and translocation of the...
Massive sulfide deposits and volcanism
Charles A. Anderson
1969, Economic Geology (64) 129-146
Massive sulfide deposits, consisting of pyrite and/or pyrrhotite and various ratios of chalcopyrite, sphalerite, and galena, are commonly associated with volcanic rocks that accumulated in eugeosynclines. Later deformation may leave an imprint of regional metamorphism. Two-thirds of the deposits mentioned in this review are about equally divided between silicic and...
Unstable sulfur compounds and the origin of roll-type uranium deposits
H.C. Granger, C. G. Warren
1969, Economic Geology (64) 160-171
Anomalous concentrations of iron sulfides found at roll fronts are believed to result from limited oxidation and mobilization of reduced sulfur species from earlier formed pyrite within the more extensively oxidized core of the roll. Laboratory experiments and chemical theory suggest that the reactions need not be biogenic, and that...
Water analysis
Marvin J. Fishman, B.P. Robinson
1969, Analytical Chemistry (41) 323-360
No abstract available....
Adoption of a nestling house mouse by a female short-tailed shrew
Lawrence J. Blus, D.A. Johnson
1969, American Midland Naturalist (81) 583-584
A nursing female short-tailed shrew (Blarina brevicauda) adopted a nestling house mouse (Mus musculus). The mouse was observed in the nest with the female and her litter of shrews three days after it was introduced into the aluminum box containing the shrews,...
Rate of sulfuric acid formation in Yellowstone National Park
Robert Schoen
1969, Geological Society of America Bulletin (80) 643-650
Sulfuric acid forms near sulfurous hot springs as the result of oxidation of hydrogen sulfide exhalations by atmospheric oxygen. This strong acid rapidly alters the surrounding rocks and can destroy man-made structures and contaminate streams. Four tracts of acid-altered ground in Yellowstone National Park were studied in order to determine...
New thrusts in ground water
C. L. McGuinness
1969, Groundwater (7) 7-10
Four principal trends in ground water are apparent:(1) Increasing use of ground water for domestic supplies. Geohydrologists must learn to quantitatively evaluate the supply under conditions of maximum development, not merely determine the availability of a supply that does not strain the aquifer. (2) Aquifers will be looked to increasingly...
Lead and strontium isotopes in volcanic rocks from northern Honshu, Japan
Carl E. Hedge, Roy J. Knight
1969, Geochemical Journal (3) 15-24
Isotopic compositions of lead and strontium and concentrations of lead, uranium, thorium, rubidium, and strontium were measured in a suite of volcanic rocks, ranging from basalt to rhyodacite in composition, and in granite and gabbro xenoliths from a traverse across northern Honshu. The observed 238U/204Pb (μ) ratio ranges from 2.4 in...