Showing papers in "Geochimica et Cosmochimica Acta in 1982"

TL;DR: Abrasion combined with an improved paramagnetic separation technique eliminates 90 to 100 percent of discordance so that ages of unprecedented accuracy (± 1 to 3 my) can be achieved for virtually all 2700 my old zircon populations from plutonic or volcanic rocks as mentioned in this paper.

TL;DR: In this paper, the authors compared the solubility of calcite, aragonite, and vaterite in CO2-H2O solutions between 0 and 90°C using the Debye-Huckel individual ion activity coefficients.

TL;DR: In this paper, the Ogueil Cl meteorite and all previous Cl chondrite analyses were employed to develop a new solar system abundance table, including the standard deviation and number of analyses for each element.

TL;DR: In this article, the Methylphenanthrene Index (MPI) was introduced, which exhibited a very good correlation with vitrinite reflectance data, and is the first maturity parameter which is based on a series of aromatic hydrocarbons.

TL;DR: In this paper, it is shown that changes in the nutrient element chemistry of sea water can be the cause of changes in CO2 to air ratios in the gas trapped in bubbles in ice of glacial age.

TL;DR: In this article, a second order rate law was established for the partial exchange of sulfur isotopes between aqueous sulfates and sulfides in a Na-bearing H2-pH system.

TL;DR: In this article, it was shown that most of the acidic functional groups of the adsorbed organic matter are neutralized by protons from solution. But the organic coating is expected to have a great influence on subsequent adsorption of inorganic cations and anions.

TL;DR: Viscosity measurements for amorphous silica and liquids belonging to the systems SiO2-M, SiO 2-Al2O3-M as mentioned in this paper, where M is an alkali-earth metal oxide, MnO, or alumina, and where N = Na2O or K2O.

TL;DR: Boninites are unusual high MgO-high SiO2 volcanic rocks found in several western Pacific island arcs as mentioned in this paper, and evidence for both enrichment and depletion of incompatible elements suggests that boninites were derived from refractory peridotite which has been metasomatically enriched in LREE, Zr, Sr, Ba and alkalis.

TL;DR: Aromatic distribution patterns have been evaluated for a series of twenty-four German high volatile bituminous B to low volatile B-to-low volatile Bituminous coals of Upper Carboniferous Westphalian C-, B- and A-ages using high performance liquid chromatography and glass capillary gas chromatography.

TL;DR: In this paper, a new model was proposed that is based on the hypothesis that the observed concentrations of molecular water and hydroxyl groups in hydrous silicate glasses reflect those of the melts from which they were quenched.

TL;DR: In this article, a set of non-linear equations can be solved with the aid of a computer using'a Newton-Raphson technique, which takes account of aqueous ion complexing, oxidation-reduction equilibria, activity coefficients, non-unit water activity and solid solutions.

TL;DR: In this article, the solubility and stability relations among these four minerals and gibbsite are plotted as a function of pH and sulfate activity at 298 K. These equilibrium calculations predict that both sulfate and aluminum can be immobilized in acid waters by the precipitation of aluminum hydroxysulfate minerals.

TL;DR: Vanadium and nickel concentrations in bitumens extracted from a variety of organic sedimentary rock types of different geological ages and geographical areas range from less than 0.2 to 4760 ppm and less than 7 to 1240 ppm, respectively.

TL;DR: In this paper, the authors derived an empirically derived equation of the form: log m = A + B(log V) + C(logV)2 where m is the molal silica concentration, V is the specific volume of pure water, and A = −4.66206 + 0.0034063T + 2179.7T−1 − 1.1292 × 106T−2 + 1.0014180T − 3.9465 × 10−4T T is temperature in kelvins.

TL;DR: In this article, a simple model is proposed to explain the high δD values, and the relationships between δ D values and the concentration of H 2 in the acid residues of carbonaceous meteorites.

TL;DR: In this paper, relative enthalpy measurements on quartz, cristobalite and amorphous SiO2 between 1000 and 1800 K were reported, and the authors derived a consistent set of thermodynamic data for these phases.

TL;DR: In this article, a computer program is developed to calculate the composition and aqueous speciation of geothermal reservoir waters including pH, redox potential and gas partial pressures, which is specifically suited to handle geochemical data from wet-steam wells, hot-water wells and boiling hot springs, but it may also be used for non-thermal waters.

TL;DR: Chlorine trifluoride (ClF3) is recommended as a comparable alternative to bromine pentafluorides (BrF5) for the quantitative extraction of oxygen from silicate minerals as discussed by the authors.

TL;DR: In this paper, a sample of mid-ocean ridge basalt glass and diabase has been reacted with seawater at 150-300°C, 500 bar, and water/rock mass ratios of 50, 62, and 125, using experimental apparatus which allowed on-line sampling of solution to monitor reaction progress.

TL;DR: In this article, the Raman spectra of crystalline calcium aluminate, anorthite and silica polymorphs are discussed in relation to their crystal structures, and compared with the corresponding glasses.

TL;DR: In this paper, the results of intramolecular isotopic analyses are combined with molecular-average isotopic compositions determined by total combustion in order to show that fatty acids biosynthesized by Escherichia coli grown aerobically with glucose as the sole carbon source and harvested at late log phase are depleted by approximately 3% in 13 C relative to the glucose.

TL;DR: In this paper, a surface diffusion crystal growth model is used to describe the combination of kinetic isotope effects on thermodynamic isotope fractionation during rapid diffusion controlled crystal growth, and an estimate of equilibrium ϵHCO3-Calcite of between −1.83 ± 0.32 and −2.26 −0.31% is calculated from slow precipitation runs.

TL;DR: In this paper, the authors show that goethite particles added to surface water samples from four lakes of widely-differing chemistry become negatively charged because of the adsorption of humic substances.

TL;DR: One hundred thirty two new measurements of the relative abundances of the stable isotopes of silicon in terrestrial materials are presented in this paper, and the total variation of δ30Si found is 6.2%., centered on the mean of terrestrial mafic and ultramafic igneous rocks, δ 30Si = −0.4%.. Igneous rocks show limited (1.1%.) variation; coexisting minerals exhibit small, systematic silicon isotopic fractionations that are roughly 13 the magnitude of concomitant oxygen isotope fractionations at 1150°

TL;DR: In this article, the adsorption of the major ions of seawater (Na, Mg, Ca, K, Cl, and SO4) on goethite (αFeOOH) from NaNO3 solutions and from major ion seawater was compared.

TL;DR: In this paper, the transfer and exchange equations for metamorphic and igneous pyroxene minerals are combined with experimental data for Fe-free pyroxenes, to produce the following equations for the Cpx slope of the solvus surface: > 1080°C: T = 1000(0.468 + 0.304 ln (1−2 [Ca])), and the following equation for the temperature-dependence of the Mg-Fe distribution coefficient:T = 1130(ln Kp+ 0.505), where T is absolute temperature, X