Showing papers in "Geochimica et Cosmochimica Acta in 1980"

TL;DR: In this article, the authors derived a differential rate equation for silica-water reactions from 0-300°C based on stoichiometry and activities of the reactants in the reaction SiO2(s) + 2H2O(l) = H4SiO4(aq) ( ∂a H 4 SiO 4 ∂t ) P.T.

TL;DR: The deuterium concentrations (δD vs SMOW) of biogenic methanes from world-wide occurrences range from −180 to −280% and were found to be depleted in deutrium by approx. 160%.

TL;DR: In this article, the alkali and alkaline earth compositional changes in the Toorongo Granodiorite weathering profile are typical of changes occurring during weathering of the continents, consequently the following generalizations apply to continental weathering.

TL;DR: In this paper, the changes in configuration at a number of chiral centres in certain acyclic isoprenoid alkanes, steranes, rearranged steranes and triterpanes of the hopane type in a suite of fourteen Toarcian shales (Paris Basin) have been determined by gas chromatography and combined GC-mass spectrometry.

TL;DR: A chemical model of the seawater system, NaK,Mg,Ca,Cl,SO 4,H 2 O, was developed for predicting mineral solubilities in brines from zero to high ionic strengths as discussed by the authors.

TL;DR: In this paper, a series of polycyclic aromatic hydrocarbons (PAH) derived by early-diagenetic transformations of biogenic precursors are found in Recent sediments of four lakes ( Lake Lucerne, Lake Zurich, Lake Greifensee, and Lake Washington, northwest U.S.A.).

TL;DR: In this article, a detailed study was made of the solvent extractable monocarboxylic, dicarboxylated and hydroxylated fatty acids and n-alkanes in a surface intertidal sediment, and the distributions compared to microorganisms cultured from the sediment.

TL;DR: In this paper, a comparison of theoretical and analytical equilibrium constants based on the reactions CH4 + 2H2O = CO2 + 4H2, 2NH3 = N2 + 3H2 and FeS2 + H2 + aluminium-silicate was made.

TL;DR: In this paper, the enthalpies of solution of a suite of 19 high-structural state synthetic plagioclases were measured in a Pb2B2O5 melt at 970 K.

TL;DR: In this article, the properties of 32 dissolved thorium species and 9 thorium-bearing solid phases have been collected from the literature, critically evaluated and estimated where necessary for 25°C and 1 atm pressure.

TL;DR: In this paper, the sorption of eleven metals on the humic acid of an aqueous solution containing Hg(II), Pb, Cu, Al, Ni, Cr(III), Cd, Zn, Co and Mn, was investigated with special emphasis on effects of pH, metal concentration and HA concentration.

TL;DR: Petrographic analyses of CM matrices characterized four phyllosilicates in Murray and Murchison meteorites and Fe- and Mg-serpentines in Nogoya as discussed by the authors.

TL;DR: In this paper, polycyclic aromatic hydrocarbons (PAH) in sediment cores from Lake Lucerne, Lake Zurich, and Greifensee, Switzerland, and Lake Washington, northwest U.S.A.

TL;DR: In this article, the authors measured in situ with benthic chambers averages 49 and 163 μmol · m −2 · hr −1 during November-May and June-October respectively.

TL;DR: In this paper, a maturity framework for oil and gas show prediction in shale-sandstone sequences containing land-derived kerogen is proposed. But the authors focus mainly on a single series of sedimentary basins in New Zealand, Colombia, Australia, and Indonesia.

TL;DR: In this paper, the average vertical distributions of pore water solutes and their sediment-water fluxes are influenced by the presence of irrigated burrows to varying degrees depending on the kind of reactions governing their behavior.

TL;DR: For example, there is a correlation between thorium and the light rare earth elements, indicated by La/Th ratios in fine grained sedimentary rocks of various ages from Australia and Greenland as discussed by the authors.

TL;DR: In this paper, the average net accumulation of individual hydrocarbons measured in a 1-yr series of sediment traps was compared with the net accumulation corresponding compounds measured in three depth intervals of 210Pb-dated bottom sediments.

TL;DR: In this paper, it was shown that the excess Pb is of eolian anthropogenic origin, through isotopic, chemical, and mass balance relationships with metals in aerosols, dry deposition, and precipitation.

TL;DR: This article showed that the biologically mediated redox fluxes of the C and S cycles have been approximately balanced through this long span of geological time, generally levelling available oxygen, consistent with the controlling mechanism proposed by Garrels and Perry (1974).

TL;DR: In this paper, three hundred and thirty new 13C analyses of diamonds are presented, indicating, in conjunction with earlier published work, a range of about 30% in the carbon isotopic composition of diamonds.

TL;DR: In this article, the Curie point pyrolysis was used to characterize the influence of short term diagenesis on the kerogen structure and the results showed that the three main types of kerogens (marine, terrestrial and mixtures of both) can be characterized using these techniques.

TL;DR: In this paper, chemical analyses of the gas compositions for 34 thermal systems were considered and an empirical relationship developed between the relative concentrations of H2S, H2, CH4 and CO2 and the reservoir temperature.

TL;DR: In this paper, a model of continental crust extraction from a uniform depleting mantle with crustal recycling is presented. But the model does not support a steady-state model for the crust.

TL;DR: In the Nelson area of New Zealand, intrusion of the Separation Point Batholith 114 Ma ago caused thermal metamorphism in the adjacent Devonian Rameka Gabbro that allowed radiogenic 40Ar to diffuse partially out of hornblendes in the gabbro as mentioned in this paper.

TL;DR: Among the spinel peridotite nodules from Dreiser Weiher as mentioned in this paper, one group (Ib) is anhydrous while the second one (Ia) is characterized by the presence of amphibole and/or breakdown-products of amphiboles.

TL;DR: In this article, the authors measured dissolution rate as a function of degree of undersaturation on shells of individual species of coccoliths and foraminifera, various size fractions of sediment from the Ontong-Java Plateau and the Rio Grande Rise, a collection of large pteropods, and on synthetic calcite and aragonite powder.

TL;DR: In this paper, the partitioning of La, Sm, Dy, Ho and Yb between calcic clinopyroxene, calcic amphibole and andesitic and basaltic liquids has been studied experimentally.

TL;DR: Magnesium/calcium, Sr/Ca, and Na/Ca atom ratios were determined in the calcite and aragonite regions of Mytilus edulis shells which were grown in semi-artificial "seawater" solutions having varying Mg/C, Src, and N/Ca ratios by instrumental neutron activation, atomic absorption and electron microprobe analytical techniques as mentioned in this paper.

TL;DR: In this article, seven documented and fresh glassy selvages from ocean floor basalt pillows were analyzed for trace elements including Ag, Au, Bi, Br, Ni, Pd, and Zn using radiochemical activation analysis.