Showing papers in "Chemical Geology in 2005"

TL;DR: CA-TIMS as discussed by the authors uses high-temperature treatment to anneal zircon lattice radiation damage from natural alpha, alpha recoil, and spontaneous fission processes; this annealing eliminates elemental and isotopic leaching effects that have limited earlier efforts at chemical leaching or multi-step step-wise dissolution or partial dissolution analysis (PDA)

TL;DR: In this paper, the development of a sequential extraction procedure for iron in modern and ancient sediments is presented, which recognizes seven operationally derived iron pools: (1) carbonate associated Fe (Fe carb ), including siderite and ankerite; (2) easily reducible oxides (Fe ox1 ), including ferrihydrite and lepidocrocite; and (3) reducible Oxides(Fe ox2 ), including goethite, hematite and akaganeite, (4) magnetite (Fe mag ); (5)

TL;DR: In this paper, the stability of the rutile/melt partitioning in hydrated basalt was investigated at 1.0-2.5 GPa and 900-1100 °C.

TL;DR: In this article, a combination of random and non-random selection of grains for analysis was proposed to extract the potential information contained in detrital zircons, yielding two complementary sets of age data from each sample.

TL;DR: The Durango apatite is widely distributed as a reference material for mineralogy, geochemistry and thermochronology as discussed by the authors, and it is largely confined to vugs and open fractures within the lower portion of the ore deposit.

TL;DR: In this article, a conceptual model of CO2 injection in bedded sandstone-shale sequences has been developed using hydrogeologic properties and mineral compositions commonly encountered in Gulf Coast sediments.

TL;DR: In this paper, a new analytical technique for precise and accurate in situ Hf isotope ratio measurements for zircons by means of laser ablation-multiple collector-inductively coupled plasma mass spectrometry (LA-MC-ICPMS).

TL;DR: In this paper, the authors proposed that Pacific plate subduction resulted in crustal thickening and subsequent lithospheric delamination which resulted in the upwelling of asthenospheric mantle and formation of juvenile crust by underplating of mantle-derived magma in the lower crust.

TL;DR: In this article, different kinds of isotopic tracers have been used to trace dust provenance, but special attention is focused on the use of Sr, Nd and Pb isotopes.

TL;DR: In this paper, a reactive transport modelling including reaction kinetics was performed of dissolved CO2 in the cap rock at Sleipner (37 °C, 101.3×105 Pa).

TL;DR: The products of forsterite dissolution and the conditions favorable for magnesite precipitation have been investigated in experiments conducted at temperature and pressure conditions relevant to geologic carbon sequestration in deep saline aquifers as discussed by the authors.

TL;DR: In this article, the authors evaluate the impacts of CO2 itself and an impure CO2 waste stream on geologic sequestration using reaction progress models, reactive transport simulators and analogous reactive transport experiments run in a plug flow reactor.

TL;DR: Pokrovsky et al. as mentioned in this paper measured dissolution rates of calcite, dolomite and magnesite powders at 25 °C and pH from 3 to 4 as a function of salinity and partial pressure of CO2.

TL;DR: The Jiazishan metamorphic orogenic complex is composed of potassic to ultrapotassic pyroxene syenite and associated mafic dikes.

TL;DR: In this article, a combination of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron-microprobe was used to identify the highly soluble members of melanterite, rozenite, epsomite, halotrichite, and copiapite groups.

TL;DR: The reactive behavior of a mixed fluid (supercritical CO2 and brine) under physical-chemical conditions relevant to geologic storage and sequestration in a carbon repository is largely unknown as mentioned in this paper.

TL;DR: In this article, the authors compared deep and shallow-water hydrothermal vent communities and found that the proportion of organic matter derived from chemosynthesis and photosynthesis plays a crucial role in evolution.

TL;DR: In this paper, a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS) was used for iron isotope measurement of natural samples after matrix separation by anion exchange chromatography.

TL;DR: The geochemistry of Quaternary volcanic rocks from Datong provides important constraints on the petrogenesis of continental alkali and tholeiitic basalts and lithospheric evolution in the western North China Craton.

TL;DR: The geochemistry of sulfate minerals in I-type igneous rocks and in the various related hydrothermal systems that develop from their magmas and evolved fluids is reviewed with respect to the degree of approach to isotope equilibrium between minerals and their parental aqueous species as mentioned in this paper.

TL;DR: In this paper, Pitzer et al. used the Ionic interaction approach to calculate the stability and solubility of methane hydrate in seawater and pore water equilibrated with hydrogen carbonate ions.

TL;DR: In this paper, the authors used laser-ablation inductively-coupled-plasma mass-spectrometric microanalysis with the aim of relating the chemistry of zircon to its growth environment.

TL;DR: In this article, the authors investigated the adsorption of rare earth elements (REE) onto the cell walls of Bacillus subtilis and Escherichia coli (a gram-negative bacterium) at various bacterial concentrations and found that the distribution coefficients of REE between the bacterial cell surface and water showed a pattern with a prominent enrichment of heavy REE (HREE), including a maximum around Sm and Eu, which was attributed to the tetrad effect.

TL;DR: In this article, the authors measured the copper and Zn isotope ratios of three ore facies in the Devonian Alexandrinka volcanic-hosted massive sulphide (VHMS) deposit, southern Urals, were measured using multi collector ICP-MS (MC-ICP-MS) and show variations linked to depositional environment and mineralogy.

TL;DR: In this paper, the abundance of 30 trace elements has been determined in the minerals of 16 well-equilibrated spinel lherzolite xenoliths by laser-ablation inductively-coupledplasma mass-spectrometry (LA-ICP-MS).

TL;DR: The Springerville-St Johns CO2 field in eastern Arizona and western New Mexico is one of more than a dozen gas fields developed within the Colorado Plateau and Southern Rocky Mountain region.

TL;DR: In this paper, the authors measured dissolution rates of diopside, forsterite (Fo100 and Fo92), wollastonite, and hornblende in NaCl solutions as a function of pH (1≤pH≤12), pCO2 (0 and 1 atm) and activity of HCO3− and CO32− (10−5≤∑CO2≤0.1 M).

TL;DR: In this article, a thermodynamic model for calculation of the phase equilibria of CO2-H2O-NaCl system is briefly described; notably, the solubility of the carbon dioxide in the aqueous phase.

TL;DR: In this paper, the authors show that the source-related REE feature of the hydrothermal fluid that migrated through either gneissic (type A) or granitic (type B) host rocks can be explained by different degrees of supersaturation or different fluid/fluorite ratios during crystallization and by complexly controlled precipitation processes under closed system conditions.

TL;DR: Wang et al. as mentioned in this paper found that the SiO2 contents in ignited rice plant samples increased generally from roots, through SL (stem and leaves), to husks, which can be explained by kinetic isotope fractionation in a Rayleigh process.