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The lower lava flow of Bed I in Olduvai Gorge, Tanganyika, carries natural remanent magnetization (NRM) having normal polarity. Thermal demagnetization experiments demonstrate the stability of this NRM. Thus the Olduvai geomagnetic polarity event, which was originally named from the upper lava...

The significant known hydrated borate mineral assemblages (principally of the western United States) in the system Na2O-CaO-MgO-B2O3-H2O are expressible in three ternary composition diagrams. Phase rule interpretation of the diagrams is consistent with observation, if the activity of H2O is generally considered to be determined by the geologic environment. The...

Rare-earth contents of 20 allanites and 13 monazites, accessory minerals from a restricted outcrop area of intrusive granitic rocks, are reported. A quantity called sigma (Σ), which is the sum of the atomic percentages of La, Ce and Pr, is used...

Although products of individual volcanic eruptions, especially voluminous ash-flow eruptions, have been considered among the best available samples of natural magmas, detailed petrographic and chemical study indicates that bulk compositions of unaltered Pleistocene ash-flow tuffs from Aso caldera, Japan, deviate significantly from original magmatic compositions. The last major ash-flow sheet...

The eucrite and howardite calcium-rich achondrites and many mesosiderites are considered as a coherent meteorite assemblage, their silicates consisting essentially of calciumpoor monoclinic and orthorhombic pyroxenes and calcium-rich plagioclase feldspar. The achondrites can be grouped according to their brecciated structure as follows: eucrites—unbrecciated and monomict brecciated achondrites; howardites—polymict brecciated achondrites....

Chemical analyses are presented for major and minor elements in two specimens of natural glass reported from Macedon, Victoria, and are compared with new analyses of glass from Mt. Darwin, Tasmania. One specimen of Macedon glass is dark, the other light; both are spongy with relatively large cavities of size...

The coexisting olivine, clinopyroxene and glass of five samples collected from the Makaopuhi lava lake in Hawaii, at temperatures ranging from 1050 to 1160°C were analysed for nickel with an electron probe microanalyser. The results strongly suggest that the distribution of nickel between these three phase pairs well obeys the...

Now that the dust has settled it is possible to assess the long term effects of the Alaskan earthquake on March 27, both on the activities of man and on the wild life of the State....

The oldest tumor so far recorded is believed to have been a hemangioma. It occurred in a bone of a dinosaur’s tail1 and thus considerably antedates the historical period. The oldest known human tumor is much younger, dating back only to the middle of the third century after Christ.1 It...

[No abstract available]...

A metalfluorechromic indicator, Calcein Blue, has been used for the back-titration of milligram amounts of EDTA in presence of gallium complexes. The indicator was used in conjunction with an ultraviolet titration assembly equipped with a cadmium sulphide detector cell and a microammeter for enhanced end-point detection....

Solubilities of sphalerite (ZnS) and galena (PbS) were determined at 300° to 500°C and 1000 bars total pressure in a chemical environment buffered...

One hundred and sixty-four F and Cl analyses of silicic welded tuffs and lavas and glass separates are presented. Comparison of the F and Cl contents of crystallized rocks with those of nonhydrated glass and hydrated glassy rocks from the same rock units shows that most of the halogens originally...

A gas-source mass spectrometer has been constructed for the precise measurement of lead isotope ratios. Sixteen analyses on 4 different preparations of the same galena made over a period of 2 months gave 95% confidence limits (per analysis) of 206Pb/204Pb= 0.080%, 207Pb/206Pb= 0.042%and208Pb/206Pb=...

Twenty-two KAr ages were determined for sanidine samples from 10 rhyolite domes of the Mono and Inyo Craters to test the applicability of KAr dating to volcanic rocks of Recent age. Comparison of the results with ‘blank’ and dosed analyses shows...

Rb and Sr contents and87Sr/86Sr values were determined for samples of eugeosynclinal sedimentary rocks, mostly graywackes, from Oregon and California. These data are compatible with the theory of anataxis of eugeosynclinal sedimentary rocks in orogenic belts to produce granitic magmas provided...

Potassium-argon analyses of P-207 in twenty-four laboratories and rubidium-strontium analyses in ten laboratories indicate that for material of this typo the average interlaboratory precision for KAr ages is 2.6% and for RbSr ages is 3.4%, and the average intralaboratory precision for KAr ages is 1.6% and for RbSr ages is...

A base surge, first identified at the Bikini thermonuclear undersea explosion, is a ring-shaped basal cloud that sweeps outward as a density flow from the base of a vertical explosion column. Base surges are also common in shallow underground test explosions and are formed by expanding gases which first vent...

The isotopic composition of lead in Red Sea chloride brine containing 0.5 ppm Pb is found to be similar to that of some Cenozoic ore leads such as galena at Rabigh in Saudi Arabia that may have formed during mineralization accompanying Tertiary...

A paleomagnetic and K-Ar dating study of 44 upper Miocene and Pliocene volcanic units from the western United States suggests that the frequency of reversals of the earth's magnetic field during Pliocene time may have been comparable with that of the...

Ground-water reservoirs and the overlying unsaturated zone-collectively, the "subsurface"-have an enormous capacity to supply water to wells and useful plants, to store water to meet future needs for the same purposes, and, under suitable precautions, to accept wastes. This capacity can be exploited on a maximum scale, however, only on...

We conduct a first investigation into the ion-molecule chemistry of the upper Jovian atmosphere. Experimental results show that intense ultraviolet radiation reacts with the constituents of the Jovian atmosphere to produce C2H4, C2H6, C3H8, and higher polymers. The general procedure for calculating both equilibrium and nonequilibrium abundances of these products...