Showing papers in "Geochimica et Cosmochimica Acta in 1973"

TL;DR: In this paper, Krogh et al. developed a simple procedure for the decomposition of zircon and the extraction of U and Pb for isotopic age determinations.

TL;DR: In this article, an empirical method of estimating the last temperature of water-rock interaction has been devised, based upon molar Na, K and Ca concentrations in natural waters from temperature environments ranging from 4 to 340°C.

TL;DR: In this article, the best values for constituents determined in a rock analysis and for trace elements are collected for samples prepared by the Centre de Recherches Petrographiqueset Geochimiques, France, the Canadian Standard Reference Materials Project (formerly SSC), the Geological Survey of Japan, the National Institute for Metallurgy, South Africa, the U.S. Geological Survey and the Zentrales Geologisches Institut, D.D.R.

TL;DR: In this paper, the relative and absolute abundances of chondrites were determined by mass-spectrometric stable isotope dilution techniques and a comparison was made with the results on the chondrite composites previously investigated.

TL;DR: The results of these analyses were categorized on a chemical basis and the sample data were placed in three groups: Group I, Ti not detected; Group II, Ti detected; and Group III, Sr concentrators present as discussed by the authors.

TL;DR: In this paper, the solubility of gold in aqueous sulphide solutions has been determined from pH20°C ≈ 4 to pH20µc ≈ 9.5 in the presence of a pyrite-pyrrhotite redox buffer at temperatures from 160 to 300°C and 1000 bar pressure.

TL;DR: In this article, phase equilibria determined in high-pressure studies of the systems Mg2Si2O6-CaMgSi 2O6 and MgSiO3-Mg3Al2Si3O12 can be used to estimate equilibration conditions of ultramafic rocks containing the assemblage enstatite + diopside + garnet.

TL;DR: A model is developed to explain the isotope fractionation effects produced in laboratory experiments involving the reduction of sulphate to hydrogen sulphide by the bacterium Desulfovibrio desulfuricans, which differs from previous ones in its use of zero-order kinetics.

TL;DR: In this article, the adsorption of metal ions was measured and alkalimetric titrations were performed on a synthetic sample of hydrous manganese dioxide, and the affinity of the metals for the surface followed the order: Mg.

TL;DR: The distribution of Mg2+ between calcite and solution at the entire temperature range is heterogeneous, closely following the Doerner-Hoskins (Doerner and Hoskins, 1925) distribution law.

TL;DR: The solution rate of biogenic opal in near-surface sediments in the Central Equatorial Pacific is three to eight orders of magnitude lower than similar acid-cleaned samples as mentioned in this paper.

TL;DR: In this article, the authors used the surface levels of the deposits analyzed, there is nearly an order of magnitude more unsupported than supported Th-228, indicating that both radium and thorium isotopes are removed from solution in these coastal zones quite rapidly after introduction or formation.

TL;DR: The relationship between the redox state of deposition, early diagenesis, and pore water chemistry is investigated in this paper, where a diagenetic model is used to predict the measured interstitial water concentrations of alkalinity, ammonia and phosphate from reactions involving the decomposition of organic material by the reduction of pore waters SO42− and the authigenic precipitation of CaCO3.

TL;DR: In this article, the capacity of Co, Zn, Ca, Na, and Na at pH 4 was investigated at 24.0 ± 0.5°C and pH 4.

TL;DR: In this paper, a review of the available data on the carbon isotopic composition ranges of carbonatite and kimberlite carbonates shows that they are similar and overlap that of diamonds.

TL;DR: In this article, the authors analyzed two thousand and twenty well-characterized coral specimens from 17 localities and found that skeletal strontium for a given genus decreases with increasing water temperature, a relationship which previously eluded detection.

TL;DR: Perylene was found in a variety of marine sediments, in a shale and in peat, and it is suggested that its precursors arise predominantly from land organisms and are carried into oceanic traps along with detrital minerals as mentioned in this paper.

TL;DR: The distribution and rates of accumulation of Mo in marine deposits have been determined and compared with the same parameters for U and Mn as discussed by the authors, and the average Mo accumulation rate in these environments is about 1000 μg Mo/cm 2 /1000 yr; thus only 0·23 per cent of the world ocean area need be such reducing sites.

TL;DR: In this article, it was shown that the dissolution of albite includes the exchange of sodium for hydrogen ion in a surface layer of the mineral and the structural collapse of the residual anionic lattice of the layer.

TL;DR: In a salt marsh environment, plant-produced fatty acids and aliphatic hydrocarbons undergo significant modification upon being deposited in sediment as discussed by the authors, including alteration of the distribution pattern of straight chain components, increase in the concentration of branched components and decrease in unsaturated components.

TL;DR: In this paper, the magnitude of isotopic fractionation of distilled water and of 0.01 N NaCl forced to flow at ambient temperature under a hydraulic pressure drop of 100 bars across a montmorillonite disc compacted to a porosity of 35 per cent by a pressure of 330 bars.

TL;DR: In this paper, the relative retardation by geological membranes of cations and anions generally present in subsurface waters was investigated using a high pressure and high temperature "filtration cell".

TL;DR: In this paper, surface area measurements as well as organic carbon, nitrogen and phosphorus analyses on various grain size fractions of carbonate mud samples confirm that surface sorption processes take place which are similar to those described earlier for dissolved organics and artificially suspended calcite particles in both seawater and synthetic solutions.

TL;DR: In this article, water samples from Narragansett Bay and the Providence River, and fulvic acid/ saline water solutions were examined for their ability to solubilize n-alkane (n-C16 and n-C20), isoprenoid (pristane) and aromatic (phenanthrene and anthracene) hydrocarbons and dibutyl phthalate.

TL;DR: In this article, the authors measured 9 volatile elements (Ag, Bi, Cs, In, Rb, Tl, Se, Cd, Zn) by neutron activation analysis in 11 LL- and 10 E-chondrites.

TL;DR: In this article, the authors measured 17 trace elements (Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Rb, Re, Sb, Se, Te, Tl, U, and Zn) in eight C1 samples (1 Alais, 3 Ivuna, 4 Orgueil and in three C2 samples (one each of Mighei, Murchison, Murray).

TL;DR: The photosynthetic fractionation of carbon isotopes by blue-green algae in laboratory culture is dependent in a non-linear fashion on the CO 2 concentration in the feed gas as mentioned in this paper.

TL;DR: In this paper, the authors measured the amount (per cent) and δ5C13 of the organic carbon in the sediment at intervals within each core and concluded that the major parameter affecting the δC13 values of organic carbon from marine sediments is the relative amount of terrestrial material present in the sediments.

TL;DR: The amphibole pargasite [NaCa2Mg4Al(Al2Si6))O22(OH)2] in the melting range has been determined at total pressures (P) of 1.2 to 8 kbar as discussed by the authors.

TL;DR: Humic acid extracted from a podzolic soil developed under Eucalyptus delegatensis and Pteridium aquilinum in northwestern Tasmania exhibits very strong solvent activity towards a number of minerals and metals as mentioned in this paper.