Showing papers in "Geochimica et Cosmochimica Acta in 1957"

TL;DR: In this paper, Niee's and Solenhofen standards were compared to the Chicago PDB standard for carbon and oxygen isotope ratios, and the correction factors for instrumental effects and for the nature of the mass spectra were derived.

TL;DR: In this article, the authors show that the reaction can be demonstrated in the laboratory under conditions similar to those in nature by letting dilute acid percolate through crushed lava and then through limestone: iron dissolved from the lava is precipitated in the limestone and the solution is left with a high Mn/Fe ratio.

TL;DR: In this article, the concentrations of gallium, germanium, cobalt, chromium, and copper have been determined spectrographically in eighty-eight iron meteorites, including representatives from all structural classes, and in nine stony-iron meteorites.

TL;DR: In this paper, the nitrogen isotope ratio of each fraction has been measured relative to atmospheric nitrogen, and a kinetic isotope effect has been calculated on the basis of the formation of nitrate from atmospheric ammonia.

TL;DR: The tritium produced during the Castle operation in the spring of 1954 has been used to study the circulatory rates for waters in the northern hemisphere, particularly in the Mississippi Valley.

TL;DR: In view of the discordant theories for the mechanism of sedimentation of silica in natural waters, chemical properties of amorphous silica have been studied further as mentioned in this paper, and the optimum pH for the precipitation of colloidal silica is about 4·5 in contrast to that of about 8 for molecularly dispersed silica.

TL;DR: In this paper, the concentrations of nickel, cobalt, gallium, palladium and gold have been determined in 45 iron meteorites including representatives from all structural classes including hexahedrites, nickel-poor ataxites and coarse and coarsest octahedrite.

TL;DR: In this article, the process of zone refining or zone melting is described and the geological possibility of the process and its application to potassic basalts are discussed. And some sodic basalts were attributed to fractional crystallization modified by reaction with mantle material.

TL;DR: Lithium, rubidium and caesium have been determined on 186 samples and Rubidium and Caesium on an additional 53 samples, representing sedimentary and igneous rocks from geographically diverse areas and ranging in age from Pre-Cambrian to recent as mentioned in this paper.

TL;DR: In this article, the uranium and barium contents of some meteorites (4 chondrites and 1 achondrite), a basalt and a dunite have been determined by neutron activation.

TL;DR: In this article, the S34/S32 ratios in various sulphur compounds of igneous origin were determined and the present results on the distribution of S34 in them are in good agreement with those found by earlier workers.

TL;DR: In this paper, the mechanism of metamorphism has been studied from the standpoint of isotopic composition, and the results are not conclusive, but suggest that metamorphisms is associated with a depletion of O18.

TL;DR: In this article, a series of investigations on the mineral-reactions in rocks under metamorphic conditions studies on three very common lime-free clays are reported, and the results show that the illite of the clays recrystallizes below 400°C forming muscovite, chlorite or serpentine and quartz, thus giving rise to phyllites.

TL;DR: In this paper, a colorimetric method was used to identify the most abundant hosts of zirconium in igneous rocks, including rutile, sphene, magnetite, ilmenite, and apatite.

TL;DR: In this article, a complete series of solid solutions between CaCO3 and MnCO3 (manganoan calcites and calcian rhodochrosites) exists above 550°C at CO2 pressures sufficient to prevent decomposition.

TL;DR: In a continuation of a study reported previously, rare-earth elements and thorium have been determined in monazite, allanite, cerite, bastnaesite, and a number of miscellaneous cerium-earth minerals as discussed by the authors.

TL;DR: A large body of evidence to show that lognormal-type distributions are very common indeed can be found in a histogram of grain-size distribution of pyroxene from the Merensky Reef, Bushveld Igneous Complex as mentioned in this paper.

TL;DR: In this article, the daughter product diffusion was examined in detail, and developed in graphical form, and the results of such graphical application of diffusion theory were given for several zircon concentrates and monazite samples, and values of the Pb diffusion coefficient between 10−21 cm2/sec and 10−22 cm2

TL;DR: In this article, the metal/silicate and metal/sulphide fractionations for nickel in the stony-iron and iron meteorites, respectively, have been made.

TL;DR: In this paper, the tritium and helium-3 contents of six iron and five stone meteorites are measured by neutron activation, and it is shown that the He3 and Li6 contents of these meteorites were due to spallation caused by high energy costnic rays rather than slow neutrons and that the average slow-neutron flux has been less than 1 neutron/cm2 sec.

TL;DR: In this article, the geochemistry of thorium isotopes in the hydrosphere, particularly in the ocean, was studied by using a double-emulsion technique, where the thorium tracer was first precipitated with Fe(OH)3 as carrier, and the final fraction was obtained as the citric complex.

TL;DR: In this paper, the Gibbs-Duhem equation was used to estimate the partial molar volumes of simple electrolytes at different temperatures, and it was shown that at low concentrations, the ionic volumes of the ions are approximately additive.

TL;DR: The observed range in nickel content of iron meteorites may be explained by their having differentiated during the crystallization of an originally homogeneous iron melt containing 11 % nickel which formed the core of a typical parent meteorite body as mentioned in this paper.

TL;DR: In this article, samples of river water and sea water, as well as samples of sediment from the Baltic Sea region, have been examined to study the geochemistry of uranium on typical shelf zones.

TL;DR: The A 40 /K 40 ratio for coarse and fine-mesh samples of 100m.y.-old feldspar (perthitic orthoclase-microline) were compared with those for coarse-and fine-measurable samples of lepidolite from the same pegmatite and found to be in agreement, although there was some evidence for migration of argon from the potash feld spar phase to the soda feld'spar phase of the perthite as discussed by the authors.

TL;DR: In this paper, the abundance of germanium was found to be about 10 p.p.m. for the earth's crust, as compared to gold-schmidt's values of 55 p. p.m., and 1 p.n.p., respectively.

TL;DR: In this article, the following averages for tin have been obtained: chondrites 1 p.p.p., metal phase of chondites 5 p.m., iron meteorites roughly 2 p. p.n.

TL;DR: Two samples of NH 4 C1, two of caliche, eight of Wealden coal, five of Carboniferous coal, three of living trees and one air sample were studied as mentioned in this paper.

TL;DR: In this paper, an analysis of the X-ray spectra of various minerals such as brucite, gibbsite, kaolin family minerals, and montmorillonites in various states of dehydration is presented.