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Showing papers in "Geochimica et Cosmochimica Acta in 1994"


Journal ArticleDOI
TL;DR: The relationship between organic carbon (OC) and grain size found in most continental shelf sediments is reinterpreted in terms of the surface area of the sediments in this article.

1,028 citations


Journal ArticleDOI
TL;DR: A review of the available information on global Hg cycling shows that the atmosphere and surface ocean are in rapid equilibrium; the evasion of Hg0 from the oceans is balanced by the total oceanic deposition of hg(II) from the atmosphere as mentioned in this paper.

1,027 citations


Journal ArticleDOI
TL;DR: In this paper, a study of U(VI) adsorption by ferrihydrite was conducted over a wide range of U (VI) concentrations, pH, and at two partial pressures of carbon dioxide.

873 citations


Journal ArticleDOI
TL;DR: In this paper, the equilibrium fractionation factors of oxygen and hydrogen isotopes between liquid water and water vapor have been precisely determined from 25 to 350°C on the VSMOW-SLAP scale.

751 citations


Journal ArticleDOI
TL;DR: In this article, a rate law that integrates the effects of temperature, pH, ionic strength, and saturation conditions on the overall dissolution and precipitation rates of minerals is proposed, with special attention to the important effects of deviation from equilibrium on the rates of mineral-water reactions.

682 citations


Journal ArticleDOI
TL;DR: In this paper, a new method is explored for estimating the residence time of suspended particles by combining the Ce concentration data of dissolved and surface-bound phases with the Ce(III) oxidation rate measurements of MOFFETT (1990).

644 citations


Journal ArticleDOI
TL;DR: The seasonal variation in oxidized and reduced pools of Mn, Fe and S, as well as the rates of SO42− reduction, were studied in a fine-grained sediment as mentioned in this paper.

634 citations


Journal ArticleDOI
TL;DR: In this article, a series of batch and mixed flow reactor experiments were performed to determine the effect of SO42−, Cl−, ionic strength, and dissolved oxygen on the rate of reaction of pyrite with ferric iron.

625 citations


Journal ArticleDOI
TL;DR: In this article, a calibrated chemical extraction scheme was developed for partitioning reactive Fe(III) minerals in the solid phase of marine sediments, and the following chemical extractants were used: ascorbate, oxalate, dithionite, and HC1 (0.5 M).

620 citations


Journal ArticleDOI
TL;DR: In this article, a thin layer of ~50 μm diamonds is placed above a layer of peridotite powder, and partial melt is extracted from the pore spaces between the diamonds and equilibrates diffusively with the residual peridotoite mineralogy.

568 citations


Journal ArticleDOI
TL;DR: In this article, a series of long-chain n-alkanes derived from the surface waxes of higher plants and phenolic and hydroxyalkanoic compounds produced by CuO oxidation of two major vascular plant biopolymers, lignin and cutin, were determined in marine sediments from the Columbia River basin and the Washington margin.

Journal ArticleDOI
TL;DR: The chemistries of rivers draining a variety of lithologic and climatic regions have been surveyed for the purpose of quantifying the fluxes of bicarbonate and silica from rivers with respect to bedrock lithology and runoff as mentioned in this paper.

Journal ArticleDOI
TL;DR: The effect of pH on silicate mineral dissolution rate depends on pH: below pH 4-5, the dissolution rate increases with decreasing pH, in the circumneutral region the rate is pH-independent, and at pH values above around 8 the rate has increased with increasing pH.

Journal ArticleDOI
TL;DR: This paper analyzed Pennsylvanian-Permian sandstones from near the source in Colorado to those in the platform in eastern Colorado and Kansas for major elements and a number of trace elements including the REEs.

Journal ArticleDOI
TL;DR: In this paper, the authors used SPLITT-fractionation to sort hydrodynamically surficial sediments from the Washington margin, USA, into sand- (>250, 63-250 μm), silt- (35-63, 17-35, 8-17, 3-8μm), and clay-sized (1-3, 0.5-1, 64 μm) from the shelf, where terrestrially derived vascular plant debris accounted for >95% of the organic matter.

Journal ArticleDOI
TL;DR: In contrast to what is commonly assumed, the constant pH rates are not independent of chemical affinity at far from equilibrium conditions as mentioned in this paper, rather, the logarithm of these rates for albite and kaolinite are linear functions of aqueous Al concentration over wide ranges of saturation states.

Journal ArticleDOI
TL;DR: In this article, the authors derived the equilibrium constant of the reaction quartz = SiO2(aq)log K = 4.2620 −5764.2T + 1.7513 × 106T2−2.2869 × 108T3 + [2.8454−1006.9T + 3.5689 × 105T2] log ρH2O where logK = logmSiO 2(aq).

Journal ArticleDOI
TL;DR: In this article, a positive feedback linking ocean anoxia, enhanced benthic phosphorus regeneration, and marine productivity is proposed, which suggests that O2 depletion in coastal regions caused by eutrophication may enhance P regeneration from sediments, thereby providing additional P necessary for increased biological productivity.

Journal ArticleDOI
TL;DR: In this article, vertical concentration profiles of the dissolved and suspended particulate phases were determined for a suite of reactive trace metals, Al, Fe, Mn, Zn, and Cd, during summertime at a station in the center of the North Pacific gyre.

Journal ArticleDOI
TL;DR: Renazzo chondrites have a lineation possibly caused by fluid-lubricated, impact-induced shearing as mentioned in this paper, which can be represented by six or more closely related fall events.

Journal ArticleDOI
TL;DR: In this article, the first spectroscopic evidence to indicate Fe(III)-oxyhydroxide species forming in pyrrhotite has been presented, based on X-ray photoelectron spectroscopy and Auger Electron Spectroscopy (AES).

Journal ArticleDOI
TL;DR: In this paper, a three reservoir model consisting of the continental crust, depleted mantle and a more primitive mantle reservoir is used as a basis to account for both the present-day as well as the evolving isotopic compositions of the Earth's crust and mantle.

Journal ArticleDOI
TL;DR: In this paper, rare earth element data are reported for vent fluids collected from eight deep-sea hydrothermal areas, including samples from sediment-hosted and bare-rock hydro-thermal systems, showing the same fractionation patterns exhibited by plagioclase during magma segregation.

Journal ArticleDOI
TL;DR: Apatite dissolution and solubility in the peraluminous haplogranite system were investigated in three sets of experiments at 750°C and 200 MPa (PH2o), as functions of Ap grain size, abundance (melt: Ap ratio), and melt ASI [alumina saturation index: mol. as mentioned in this paper.

Journal ArticleDOI
TL;DR: The Murchison C2M meteorite has a size distribution in the range 0.2 to 6 μm as mentioned in this paper, which can be fit either to a power-law or a log-normal distribution, but the deficiency of small grains strongly favors the latter.

Journal ArticleDOI
TL;DR: Experiments with cultured aerobic methane oxidising bacteria confirm that their biomarker lipids will be significantly depleted in 13C compared to the substrate, and have significant implications for the interpretation of specific compound isotopic signatures now being measured for hydrocarbons and other lipids present in sediments and petroleum.

Journal ArticleDOI
TL;DR: In this paper, the effect of biogenic cycling of Sr vs. Ca in the surface ocean and variable extension rate on Sr incorporation in coralline aragonite was evaluated for three coral species, Porites lobata, Pocillopora eydouxi, and Pavona clavus, collected for the Galapagos islands.

Journal ArticleDOI
TL;DR: In this article, a high-resolution (near weekly) Sr/Ca and oxygen isotopic record is presented for a coral from the Pandora Reef in the Great Barrier Reef (GBR) of Australia during the period 1978 to 1984.

Journal ArticleDOI
TL;DR: In this article, the authors examined three simple models for the formation and evolution of the fluid in the earth's mantle: 1) Mixing of hydrous and carbonatitic fluids, 2) partial melting of a carbonate-bearing source rock, and 3.

Journal ArticleDOI
TL;DR: A high-resolution seawater strontium isotope curve has been generated through the analysis of well-dated and well-preserved belemnites and oysters from the Middle and Upper Jurassic and the Lower Cretaceous of Great Britain this article.