Showing papers in "Geochimica et Cosmochimica Acta in 2009"

TL;DR: In this paper, the authors present a review and ranking of energy-related solutions to global warming, air pollution mortality, and energy security while considering other impacts of the proposed solutions, such as on water supply, land use, wildlife, resource availability, thermal pollution, water chemical pollution, nuclear proliferation, and undernutrition.

TL;DR: Shuster et al. as discussed by the authors developed and investigated a new kinetic model, the radiation damage accumulation and annealing model (RDAAM), that adopts the effective fission track density as a proxy for accumulated radiation damage.

TL;DR: In this paper, the authors used the Hf-W systematics of meteoritic and planetary samples to provide firm constraints on the chronology of the accretion and earliest evolution of asteroids and terrestrial planets and lead to the following succession and duration of events in the earliest solar system.

TL;DR: In this article, the authors used laser-ablation inductively coupled mass spectroscopy (LA-ICPMS) techniques to investigate the distribution of Ag, As, In, Mn, Mo, Ni, Pb, Sb, Se, Sri and TI in samples from 26 ore deposits.

TL;DR: In this article, a numerical model of episodic loss assuming the presence of multiple diffusion domains yields excellent fits between synthetic and actual degassing spectra, and they used this model to isolate 40Ar∗ loss from the grains that remained intact during hydrothermal treatment at 10kbar permitting calculation of diffusion coefficients in the temperature range 730-600 ˚C.

TL;DR: In this paper, numerical models are used to investigate the potential influence of chemical thermodynamics on H 2 production during serpentinization, and the results suggest that thermodynamic constraints on mineral stability and on the distribution of Fe among mineral alteration products as a function of temperature are likely to be major factors controlling the extent of H 2 output.

TL;DR: In this article, a freeze-dried Si co-precipitated ferrihydite species (Si-ferrihydrite) was used to investigate the effect of Si adsorption on the formation of Fe(III) oxyhydroxides.

TL;DR: In this article, the solubility of REE(III) fluoride solids was determined in fluoride- and chloride-bearing solutions at 150, 200 and 250 C and saturated water vapor pressure.

TL;DR: In this article, the authors used scanning transmission X-ray microscopy (STXM), micro-X-ray fluorescence (μXRF) microscopy, and high-resolution transmission electron microscopy(HRTEM) to classify the microbial polymers that influence FeOOH mineralogy.

TL;DR: In this article, detailed petrographic, mineral chemical, magnetic and Mosbauer analyses of partially to fully serpentinized peridotites from the Ocean Drilling Program (ODP) Leg 209, Mid-Atlantic Ridge (MAR) 15°N area are presented.

TL;DR: In this paper, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka marine terrace chronosequence near Santa Cruz, CA.

TL;DR: In this article, the authors investigated Hg isotope fractionation during photoreduction and its relationship with Hg/DOC ratios and found that mass dependent (MDF) and mass independent fractionation (MIF) was observed.

TL;DR: In this article, the authors investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM).

TL;DR: In this article, the authors examined the provenance of isoprenoid and branched glycerol dialkyl tetraether lipids in lake sediments and their potential application as palaeoenvironmental and palaeoclimatic proxies.

TL;DR: In this paper, a theoretical model of the kinetic isotope effects associated with phosphoric acid digestion of carbonates is presented, based on structural arguments that the key step in the reaction is disproportionation of H 2CO_3 reaction intermediary.

TL;DR: In this article, the isotopic fractionation of Mo during adsorption to a range of Fe (oxyhydr)oxides, under variable Mo/Fe-mineral ratios and pH, was investigated.

TL;DR: In this article, the authors estimate nutrient production rates using the standard estuarine model and a non-steady-state box model, separate nutrient fluxes associated with fresh and saline submarine groundwater discharge (SGD), and estimate offshore fluxes from radium isotope distributions.

TL;DR: In this article, a model describing the temporal and spatial evolution of calcite nucleation on the surface of Synechococcus leopoliensis PCC 7942 was developed.

TL;DR: A multisite surface complexation (MUSIC) model for ferrihydrite (Fh) has been developed in this article, where the surface structure and composition of Fh nanoparticles are described in relation to ion binding and surface charge development.

TL;DR: In this paper, the authors used a conceptual evaporation model of back condensation fluxes within a thin layer at the liquid-vapor interface to calculate the fraction of liquid Hg vapor above the liquid at chemical equilibrium.

TL;DR: In this article, the nitrogen isotope effect was measured for microbial nitrite oxidation to nitrate, and it was shown that the fractionation is most likely inverse at the enzyme level.

TL;DR: In this paper, the authors proposed a correction procedure that attempts to calculate the δ13C values that would have been obtained under pre-industrial conditions using nonlinear regression, but the magnitude of the adjustment made is restricted by two logical constraints based on the physiological response of trees.

TL;DR: In this paper, the partitioning behavior of Cl between apatite and melt is non-Nernstian and is a complex function of melt composition and the Cl concentration of the system.

TL;DR: In this article, the authors reported new Re-Os and Mo isotope data for the Mesoproterozoic Velkerri Formation (Roper Group) and the PaleoproTERozoic Wollogorang Formation (Tawallah Group), McArthur Basin, northern Australia.

TL;DR: In this paper, the authors describe the molecular-level composition of C 18 -extracted dissolved organic matter (DOM) along an east-west transect of the North Atlantic Ocean.

TL;DR: In this article, it was shown that at ambient temperatures magnesite growth is limited by very slow step advancement rates and step generation rates have an estimated activation energy of ∼60kJ/mol.

TL;DR: Shuster et al. as discussed by the authors investigated the influence of natural radiation damage on apatite diffusion kinetics and found that at these levels, radiation damage acts to retard He diffusion in apatites, and that thermal annealing reverses the process.

TL;DR: In this article, the x-wind model vs. the shock-wave model of the origin of chondritic components and irradiation vs. stellar origin of short-lived radionuclides are compared.

TL;DR: In this paper, an approach for calculating the pore-water compositions of clayrocks from laboratory-measured properties of core samples, including their leachable Cl and SO4 concentrations and analysed exchangeable cations, and from mineral and cation exchange equilibria based on the formation mineralogy is presented.

TL;DR: The origin of polycyclic aromatic hydrocarbon (PAH) perylene in sediments and petroleum has been a matter of continued debate as mentioned in this paper, and structural similarities to perylene quinone-like components present in e.g. fungi, plants, crinoids and insects suggest a product-precursor relationship.