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Showing papers in "Chemical Geology in 1999"


Journal ArticleDOI
TL;DR: In this paper, the major dissolved carbon species in diagenetic settings are represented by the two carbon redox endmembers CH4 and CO2, and they can be tracked with the aid of carbon ( 13 C / 12 C ) and hydrogen ( D/H≡ 2 H/ 1 H ) isotopes.

2,589 citations


Journal ArticleDOI
TL;DR: In this article, newly compiled data on the 60 largest rivers of the world are used to calculate the contribution of main lithologies, rain and atmosphere to river dissolved loads, and the relationship between the chemical weathering rates of silicates and the possible controlling parameters are explored.

2,344 citations


Journal ArticleDOI
TL;DR: In this article, a total of 2128 calcitic and phosphatic shells, mainly brachiopods with some conodonts and belemnites, were measured for their δ 18 O, δ 13 C and 87 Sr / 86 S values.

2,241 citations


Journal ArticleDOI
TL;DR: In this article, a total of 2128 calcitic and phosphatic shells, mainly brachiopods with some conodonts and belemnites, were measured for their δ 18 O, δ 13 C and 87 Sr / 86 S values.

1,801 citations


Journal ArticleDOI
TL;DR: In this paper, a set of experiments on natural, hydrous basalts at 1-4 GPa constrain the composition of "unadulterated" partial melts of eclogitized oceanic crust within downgoing lithospheric slabs in subduction zones, where these same adakite melts are allowed to infiltrate and react with an overlying layer of peridotite.

1,492 citations


Journal ArticleDOI
TL;DR: In this paper, a procedure for the analysis of Cu and Zn isotope compositions by plasma-source mass spectrometry (Plasma 54) together with a method to purify Cu and zn from natural samples of silicates, ores, sediments, and biological material is presented.

1,126 citations


Journal ArticleDOI
TL;DR: In this article, a simple model of the global carbon cycle is employed to simulate a number of different perturbations, each lasting 500 ky, i.e., much longer than the residence times of carbon and phosphorus in the ocean-atmosphere system.

972 citations


Journal ArticleDOI
TL;DR: In this article, geochemical and isotope tracer analyses of postcollisional mafic-ultramafic rocks from the Dabie terrane in central China show that they could have been generated by melting of such metasomatized mantle as a result of crust-mantle interaction.

842 citations


Journal ArticleDOI
TL;DR: For the later Neoproterozoic, from 800 to 543 Ma (346 analyses), from the Cambrian through the Jurassic (1616 analyses), and from the Cretaceous and Cenozoic (2493 analyses) the abundance of 13 C in marine organic matter has been compiled as discussed by the authors.

721 citations


Journal ArticleDOI
TL;DR: Sr and C isotope data obtained on stratigraphic suites of well-preserved marine limestone from Siberia, Namibia, Canada, Svalbard and East Greenland provide a relatively detailed first-order record of isotopic variation in seawater through the late Neoproterozoic Era.

665 citations


Journal ArticleDOI
TL;DR: In this paper, river chemistry data for a network of rivers draining the western and central Nepal Himalaya is presented, including the monsoon season, for rivers in Nepal and for the Ganges and Brahmaputra in Bangladesh.

Journal ArticleDOI
TL;DR: In this article, the rare earth elements (REE) are scavenged by Fe oxyhydroxides within less than 1 m distance from the vent orifice, resulting in a strong increase of the Y/Ho ratio.

Journal ArticleDOI
TL;DR: In this paper, the geochronological evolution of early Archaean gneisses from southern West Greenland is reassessed using the well-established cathodoluminescence imaging method both to reveal previously undocumented complex zircon growth histories and to control positioning of ion-microprobe U-Th-Pb analyses.

Journal ArticleDOI
TL;DR: In this article, the authors used spinel peridotites from a variety of island arcs to calculate the redox state of the mantle wedge above subduction zones and provided further evidence that the mantle is ubiquitously oxidised relative to oceanic and ancient cratonic mantle.

Journal ArticleDOI
TL;DR: In this paper, a model is proposed by which partition coefficients of rare-earth element (REE) between apatite and water for a substitution mechanism can be extrapolated from mineral/melt partition data to seawater or sedimentary basin conditions.

Journal ArticleDOI
TL;DR: Isotopic composition of dissolved inorganic carbon (DIC) in the Ottawa River basin is about −8 and −16‰ for lowland carbonate and upland silicate tributaries, respectively as discussed by the authors.

Journal ArticleDOI
TL;DR: In this article, the coprecipitation of trace elements into insoluble fluoride precipitates in mafic and ultramafic silicate rocks was estimated quantitatively, and suggested an effective method of digestion that can suppress completely fluoride precipitation.

Journal ArticleDOI
TL;DR: In this article, the carbon and oxygen isotope data indicate that this episode may have been restricted to the early Kasimovian, a proposition at odds with the poorly dated record of glacial deposits that are interpreted as indicating a warm climate for the entire Stephanian.

Journal ArticleDOI
TL;DR: In this paper, the change in solution-phase weight average molecular weight (Mw) upon sorption of bulk (rather than isolated) surface water NOM from the Suwannee River and the Great Dismal Swamp (GDS) to goethite and kaolinite at different sorption densities and at pH 4, 22°C.

Journal ArticleDOI
TL;DR: Li contents and isotopic compositions were determined for a suite of well-characterized basaltic lavas from the Central American Volcanic Arc (CAVA) as discussed by the authors, and these correlations are particularly strong for Nicaragua samples.

Journal ArticleDOI
TL;DR: In this paper, the double-spike technique is used to circumvent this fractionation problem by determining the mass discrimination factor ϵ directly for each sample, which can be obtained after performing a second measurement on a sample aliquot to which a double spike of known, calibrated composition has been added.

Journal ArticleDOI
TL;DR: In this article, the results of ultrafiltration experiments (0.20 μm-300,000 Da-5000 Da-1000 Da) performed on natural rich-organic waters (30-40 mg l−1 of dissolved organic carbon) sampled in wetland area of Cameroon (Nsimi-Zoetele site).

Journal ArticleDOI
TL;DR: In this paper, transmission electron microscopic (TEM) analyses of freshwater biofilms and bacterial cells, grown in experimental culture, have shown that these microorganisms are commonly associated with fine-grained (Fe, Al)-silicates of variable composition.

Journal ArticleDOI
TL;DR: A currently emerging sulfur isotope record for Phanerozoic seawater, based on structurally substituted sulfate in stratigraphically well constrained biogenic carbonates, allows the detailed assessment of secular variations within the global sulfur cycle and the interaction between the sulfur and carbon cycles.

Journal ArticleDOI
TL;DR: In this article, the authors measured dissolved inorganic carbon (DIC) and PIC at 20 sites on the Rhone and its main tributaries from Switzerland to the Mediterranean, in March, September and July (flood event) 1996.

Journal ArticleDOI
TL;DR: In this article, the carbon balance of regional aquifers in Central Italy is estimated by coupling aquifer geochemistry with isotopic and hydrogeological data and the resulting production rate of deep CO 2 ranges from 4×10 5 to 9×10 6 mol y −1 km −2.

Journal ArticleDOI
TL;DR: In this article, the authors show that the B-bearing component derived from the metamorphosed slab must be enriched in 11 B relative to the slab, favoring an aqueous fluid as the slab transfer mechanism.

Journal ArticleDOI
TL;DR: In this article, a coupled chloride-hydrate numerical model was proposed to explain the pore water Cl− profile and to isolate in situ Cl− concentrations in marine sediment-pore water systems.

Journal ArticleDOI
TL;DR: In this paper, a model for barite and celestite solubilities in the Na-K-Ca-Mg-Ba-Sr-Cl-SO4-H2O system to 200°C and to 1 kbar is presented.

Journal ArticleDOI
TL;DR: In this article, the Asela-Ziway mafic and Chilalo intermediate lavas have been analyzed and shown to have a similar range of Nd and Pb isotopic ratios: 0.70392-0.70510.