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Showing papers in "Geochimica et Cosmochimica Acta in 1987"


Journal ArticleDOI
TL;DR: In this paper, chemical, physical, and mechanical changes resulting from metasomatic hydrochemical processes are developed using mass balance models which formally link chemical composition to bulk density, mineral density, volumetric properties, porosity, and amount of deformation (strain).

768 citations


Journal ArticleDOI
TL;DR: In this paper, rates of aqueous, abiotic pyrite oxidation were measured in oxygen-saturated and anaerobic Fe(III)-saturated solutions with initial pH from 2 to 9.

738 citations


Journal ArticleDOI
TL;DR: In this paper, the densities of 27 liquids in the system were measured using the double-bob Archimedean technique and the results indicated that multicomponent silicate liquid volumes have a linear dependence on composition with the exception of the TiO2 component.

670 citations


Journal ArticleDOI
TL;DR: In this article, the rate constant of Fe(II) in water and seawater was found to be a second degree function of pH over the pH range of 75 to 85 at 5°C and 60 to 80 at 25°C.

653 citations


Journal ArticleDOI
TL;DR: In this article, a computer mixing model based on six relatively immobile elements (Th, Hf, Yb, La, Sc, Co) and four source rocks indicate that the relative proportions of granite, basalt and komatiite increased with time in sediment source areas at the expense of tonalite.

633 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that the transformation of vaterite and aragonite to calcite takes place through dissolution of the metastable phase and growth of the stable phase, calcite.

556 citations


Journal ArticleDOI
TL;DR: In this article, a large scale boron exchange between seawater and the oceanic crust has been demonstrated at both high and low temperature, and the B content of altered whole rocks correlates strongly with δ18O, and increases with degree of alteration.

531 citations


Journal ArticleDOI
TL;DR: In this article, the vertical and horizontal distributions of dissolved and suspended particulate Fe and Mn, and vertical fluxes of these metals (obtained with sediment traps) were determined throughout the Pacific Ocean.

523 citations


Journal ArticleDOI
TL;DR: In this article, rare earth element concentrations in biogenic apatite of conodonts, fish debris and inarticulate brachiopods were determined in over 200 samples from Cambrian to modern sediments.

521 citations


Journal ArticleDOI
TL;DR: A general algorithm for the computation of chemical equilibria in complex systems containing non-ideal solutions has been developed in this paper, which is a G-minimization based on repeated linear and nonlinear programming steps.

512 citations


Journal ArticleDOI
TL;DR: In this article, the rate of magnetite dissolution is proportional to the concentration of dissolved pore water sulfide and the surface area of the magnetite in anoxic marine sediments.

Journal ArticleDOI
TL;DR: In this paper, rare earth carbonate and oxalate complexation constants have been determined through examination of distribution equilibria between tributyl phosphate and an aqueous perchlorate phase.

Journal ArticleDOI
TL;DR: In this article, the authors measured the 15 N 14 N of 300 marine and terrestrial organisms from the southwestern Cape of South Africa and found that high δ 15 N values for herbivores occur in areas receiving less than 400 mm of rain per annum.

Journal ArticleDOI
TL;DR: A series of C13 to C31 aryl isoprenoids (1-alkyl, 2,3,6-trimethylbenzenes) have been identified in reef-hosted oils and their source rocks from the Middle and Upper Silurian of the Michigan Basin and Middle Devonian of the Alberta Basin, Canada as discussed by the authors.

Journal ArticleDOI
TL;DR: In this paper, an experimental determination of partition coefficients (D) for Nb and Ta between Ti-rich minerals (sphene, rutile, ilmenite and Ti-magnetite) and coexisting silicate liquids of basaltic andesite and trachyte composition was performed.

Journal ArticleDOI
TL;DR: The rate of calcite recrystallization by calcite was determined as a function of pH and Mg2+ in aqueous solutions saturated with respect to calcite but undersaturated with respect of CdCO3.

Journal ArticleDOI
TL;DR: In this paper, the variation of adsorption constants and isotope fractionation with pH and temperature during the adaption of B from seawater onto marine clay has been examined.

Journal ArticleDOI
TL;DR: In this article, the adsorption coefficient for the uptake of boron from seawater by fluvial suspended material (mississippi) has an experimentally determined value of 1.54 ± 0.05.

Journal ArticleDOI
TL;DR: The authors of as discussed by the authors reported that the Merapi volcanic gas is enriched by factors greater than 105 in Se, Re, Bi and Cd; 104-105 in Au, Br, In, Pb and W; 103-104 in Mo, Cl, Cs, S, Sb, S.C., S.S., N.S. and Ag, and less than 103 g d of Ni, Cu, Cr, Ni, Ni and Co.

Journal ArticleDOI
TL;DR: In this article, a gem quality crystal of Durango fluorapatite was found to have a 4He content consistent with complete retention of radiogenic helium since its formation at about 31 Ma.

Journal ArticleDOI
TL;DR: In this article, the authors used the ion-interaction model of Pitzer and co-workers to predict mineral solubilities in binary and ternary electrolyte mixtures in the system NaCl-KCl-MgCl2-H2O.

Journal ArticleDOI
TL;DR: In this article, a method for the precise oxygen isotope analysis of NO−3 was developed, which permitted the assignment of unknown water samples to its probable source and origin, based on the known isotope abundance shifts due to isotope effects of nitrification and denitrification.

Journal ArticleDOI
TL;DR: The isotopic signature of Nd in the water column from several western North Atlantic sites and formational areas for North Atlantic Deep Water shows extensive vertical structure at all locations as mentioned in this paper.

Journal ArticleDOI
TL;DR: In this article, molecular orbital theory is used to explain a heterogeneous reaction mechanism for both pyrite oxidation and reduction, and the mechanism demonstrates that the oxidation of FeS2 by Fe(3+) may occur as a result of three important criteria: (1) the presence of a suitable oxidant having a vacant orbital (in case of liquid phase) or site (solid phase) to bind to the FS2 via sulfur; (2) the initial formation of a persulfido (disulfide) bridge between FeS 2 and the oxidant, and (

Journal ArticleDOI
TL;DR: Examples from the fields of geochronology and thermodynamics are used to highlight the advantages and the flexibility of the error propagation procedure, an alternative to computer intensive techniques such as Monte Carlo.

Journal ArticleDOI
TL;DR: In this paper, the authors measured the solubility of five natural silicate liquids as a function of temperature and partial pressure at 1 atm total pressure and diffusion coefficients of the noble gases were measured in a tholeiite basalt at 1350°C.

Journal ArticleDOI
TL;DR: In this article, high precision analyses for lithium conducted on well characterized suites of MORB and ocean island basalts suggest a bulk distribution coefficient of 0.25−0.35 and behavior which is similar to Yb during low pressure fractionation and V during melting, as long as garnet is not an important residual phase.

Journal ArticleDOI
TL;DR: Isotopic and geochemical data from the northern and central Lesser Antilles arc is presented in this paper, where a mixing model between MORB source and subducted sediment is tightly constrained in terms of the allowable proportion of sediment.

Journal ArticleDOI
Alfonso Mucci1
TL;DR: In this paper, a constant disequilibrium technique was used to determine the composition of magnesian calcite overgrowths precipitated on pure calcite seeds from artificial seawater at 5, 25 and 40°C.

Journal ArticleDOI
TL;DR: In this article, the mineral/groundmass partition coefficients for U, Th, Zr, Hf, Ta, Rb, REE, Co and Sc have been systematically measured in olivine, clinopyroxene, amphibole, biotite, Ti-magnetites, titanite, zircon and feldspars, in basaltic to trachytic lavas from alkaline series.