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Page 6584, results 164576 - 164600

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Eclogitic pyroxenes, ordered with P2 symmetry
J. R. Clark, J. J. Papike
1966, Science (154) 1003-1004
X-ray diffraction crystal-structure analysis of omphacite from eclogite, Tiburon Peninsula, Marin County, California, shows that this clinopyroxene has P2 symmetry with a nearly ordered distribution of the multiple cation content defined by its approximate formula: (Na0.5Ca0.5) (Mg 0.4Fe2+0.1Al0.4Fe3+0.1)Si2O6. Na+ and Ca2+ tend to assume alternate locations in the structure, and...
Exposure of basement rock on the continental slope of the bering sea
D.W. Scholl, E. C. Buffington, D.M. Hopkins
1966, Science (153) 992-994
Profiles of repetitive seismic reflections reveal that the Bering continental slope, outer shelf, and rise overlay an acoustically reflective "basement" which extends at least 750 kilometers parallel to the trend of the slope. This acoustic basement is usually covered by several hundred meters of stratified sediments at the top and...
Variational method of determining effective moduli of polycrystals with tetragonal symmetry
R. Meister, L. Peselnick
1966, Journal of Applied Physics (37) 4121-4125
Variational principles have been applied to aggregates of randomly oriented pure‐phase polycrystals having tetragonal symmetry. The bounds of the effective elastic moduli obtained in this way show a substantial improvement over the bounds obtained by means of the Voigt and Reuss assumptions. The Hill average is found to be a good approximation in...
Observed variations in the strontium concentration of sea water
E.E. Angino, G.K. Billings, N. Andersen
1966, Chemical Geology (1) 145-153
On samples obtained from five widely separated areas of the North Atlantic Ocean 91 determinations of strontium were made. These include surface and deep-water samples from both the cold North Atlantic area and the warm subtropical Caribbean area. The results differ from...
Nickel-iron spherules from aouelloul glass
E. C. T. Chao, E.J. Dwornik, C.W. Merrill
1966, Science (154) 759-765
Nickel-iron spherules, ranging from less than 0.2 to 50 microns in diameter and containing 1.7 to 9.0 percent Ni by weight, occur in glass associated with the Aouelloul crater. They occur in discrete bands of siliceous glass enriched in dissolved iron. Their discovery is significant tangible evidence that both crater...
Oxygen fugacities directly measured in magmatic gases
M. Sato, T. L. Wright
1966, Science (153) 1103-1105
An electrochemical device was used to measure the fugacity of oxygen (fO2) in holes drilled through the crust of Makaopuhi lava lake, Kilauea Volcano, Hawaii. Results obtained within 6 months of the lake formation show that log fO2 normally varies linearly with the reciprocal of the absolute temperature, and that...
Absence of neutral alkali atoms in rhodizite
G. Donnay, A. N. Thorpe, F. E. Senftle, R. Sioda
1966, Science (154) 889-890
The formula CsB12Be4Al4O28 has been proposed by others for the mineral rhodizite. Electron-spin-resonance and magnetic susceptibility measurements prove the absence of neutral cesium atoms. An ionic formula CsB11Be4Al4O 26(OH)2is proposed....
Shattuckite and plancheite: A crystal chemical study
Howard T. Evans Jr., Mary E. Mrose
1966, Science (154) 506-507
The orthorhombic crystal structures of shattuckite, Cu5( SiO3)4(OH)2 and planchétite, Cu8(Si4011)2(OH)4 H2O, have been solved. Shattuckite contains silicate chains similar to pyroxene in a complex association with copper atoms, while the closely related planchéite contains silicate chains similar to amphibole....
Geomagnetic polarity epochs: A new polarity event and the age of the Brunhes-Matuyama boundary
Richard R. Doell, G. B. Dalrymple
1966, Science (152) 1060-1061
Recent paleomagnetic-radiometric data from six rhyolite domes in the Valles Caldera, New Mexico, indicate that the last change in polarity of the earth's magnetic field from reversed to normal (the Brunhes-Matuyama boundary) occurred at about 0.7 million years ago. A previously undiscovered geomagnetic polarity event, herein named the "Jaramillo normal...
Some Debye temperatures from single-crystal elastic constant data
R. A. Robie, J.L. Edwards
1966, Journal of Applied Physics (37) 2659-2663
The mean velocity of sound has been calculated for 14 crystalline solids by using the best recent values of their single‐crystal elastic stiffness constants. These mean sound velocities have been used to obtain the elastic Debye temperatures θDe for these materials. Models of the three wave velocity surfaces for calcite are illustrated....