Showing papers in "Comptes Rendus Geoscience in 2011"

TL;DR: In this paper, a series of naturally occurring ferrihydrites sampled from an acid mine drainage environment were characterized and compared with synthetic 2-line Ferrihydrite using high energy X-ray total scattering and pair distribution function analysis.

TL;DR: A review of the main mechanisms involved in the mediation of mineral precipitation by microorganisms can be found in this paper, including supersaturation caused by metabolic activity, the triggering of nucleation by production of more or less specific organic molecules, and the impact of mineral growth.

TL;DR: In this article, the Linear Spectral Unmixing technique (LSU) is applied to improve the prediction of soil salinity. But the standard error of the estimate is about 12.1μS−cm−1.

TL;DR: In this paper, the authors recover inter-station surface (Scholte-Rayleigh) wave empirical Green's function (EGF) of both the fundamental and the first-higher mode using one year of continuous seismic noise records on the vertical component from 28 ocean bottom seismographs deployed in the Quebrada/Discovery/Gofar transform faults region on the East Pacific Rise.

TL;DR: The capabilities and limitations of a method called "eikonal tomography" applied to ambient noise data are discussed in this article, where surface wave wave wavefronts are tracked across an array and the gradient of the travel time field produces estimates of phase slowness and propagation direction.

TL;DR: In this article, pore spaces are classified into three groups including depositional, fabric-selective and non-fabric selective, based on thin section studies from the South Pars gas field.

TL;DR: This article reviewed the current state of knowledge of the effects of redox cycles on clay and soil behavior, with the hope that this background will encourage further investigations of these processes, and evidence clearly indicates that the means by which reduction of Fe in clay minerals occurs significantly influences the potential reversibility of the process.

TL;DR: In this paper, a seismic interferometry method was proposed to extract reflection responses from low-frequency noise signals from the coda of transmissions, which can be used to characterize the lithosphere below an array of receivers.

TL;DR: In this paper, the authors present an approach to estimate volcano interior temporal seismic velocity changes using seismic noise cross-correlations with a time resolution as small as one day, which can detect transient velocity changes that could be due to long-lasting intrusions of magma without eruptive activity or to pressure buildup associated to replenishing the magma reservoir.

TL;DR: In this article, the amplitude information carried by the ASF is discussed, and it is shown that valuable amplitude information can be recovered from the ambient seismic field through careful processing Amplitude measurements may be particularly valuable due to the enhanced sensitivity of attenuation to fluids and/or temperature fluctuations.

TL;DR: In this paper, the authors discuss the complexity of minerals, natural vs. anthropogenic inputs of elements and pollutants into the biosphere, the role of minerals in the biogeochemical cycling of elements, natural nanoparticles, and the Environmental Mineralogy of three major potential pollutant elements (Hg, As and U).

TL;DR: In this paper, new insights in the sorption mechanisms of As on Fe(II) and Fe(III) nanophases recognized to play an important role in the microbial cycling of As and Fe.

TL;DR: In this article, the authors discuss some environmental mineralogy research perspectives raised by CO 2 geological storage, and discuss the efficiency of the process and its environmental consequences in large-scale CO 2 storage.

TL;DR: In this article, strong relations between particular physical chemical properties of very small nanoparticles (size < 30 nm) and biological activity perturbations were shown. But the results were limited to the case of small size nanoparticles.

TL;DR: In this paper, the authors show how natural or archaeological analogues provide critical constraints not only on the phenomenology of glass alteration and the mechanisms involved, but also on the ability of experimental short-term data to predict long-term alteration in complex environments.

TL;DR: In this paper, the authors review three investigations of PII that demonstrate the wide range of possible applications and present a recent investigation that documented velocity variations in the shallow subsurface of the moon.

TL;DR: In this article, it is argued that noise intensity, while rarely isotropic or homogeneous, may nevertheless be modeled by a radiative transfer equation, and that this recognition sufficiently constrains the noise intensity that we may hope to fit measured correlation amplitudes to models for spatially varying attenuation and site amplification factors.

TL;DR: In this paper, the foliations, lineations, fold axes trajectories and shear zones kinematics vary from the Archean Ntem and Paleoproterozoic Nyong complexes to NeoproTERozoic Oubanguide complex.

TL;DR: In this article, it was shown that the δ11B variations measured at micrometer scale are principally controlled by biology via modification of the pH near the calcification sites.

TL;DR: In this article, a chemical background on condensation phenomena of the aluminum cation in aqueous solution is provided, and the formation of polycationic molecular clusters and nanosized solid phases of aluminum oxy(hydroxi)des is interpreted with illustrative mechanisms, building a bridge between solution chemistry and solid-state chemistry.

TL;DR: In this paper, the results from collaborative research between France and Brazil on soil and water systems, carried out in the Upper Amazon Basin, reveal the weathering processes acting in the partly inundated, low elevation plateaus of the Basin, mostly covered by evergreen forest.

TL;DR: In this article, three criteria are of special interest: compatibility with geological environment, resistance to natural fluids, and effects of self-irradiation, which is a good basis for designing ceramics which could eventually replace nuclear glasses.

TL;DR: In this paper, the authors reconstruct the surface-wave Green's function by iterating the correlation process over the tail of the noise-based correlation function, showing that some coherent signal is still present in the coda of the C 3 function.

TL;DR: In this article, anisotropy of Magnetic Susceptibility (AMS) and U-Pb geochronology in zircon fractions were carried out in a magnetite type-granite, the Lavadores granite, which is an example of a late to post-orogenic Variscan granite in northern Portugal (NW Iberian Peninsula).

TL;DR: In this article, a qualitative analysis of ocean microseism source distribution observed in North America during fall and winter months was carried out, which can be used in conjunction with wave-wave interaction maps to quantify the source distribution anisotropy.

TL;DR: The role of microbes in geological processes is discussed with particular reference to the geochemical cycle involving iron in this article, where bacterial biofilms and precipitate phases can have a major influence on fluid flow through fractures or porous media as demonstrate using experiments from micro- to macro-scales.

TL;DR: In this paper, the Lizio granite was used for dextral shearing along the northern branch of the South Armorican Shear Zone and it was therefore active at that time 40Ar/39Ar analyses on muscovite grains yielded plateau dates ranging between 3115 and 3082 Ma.

TL;DR: In this article, a solution mine was instrumented in 2004 prior to its collapse as part of the mining scheme, and a permanent monitoring system was set up, including a high-resolution microseismic network linked to a surface field-displacement measurement system.

TL;DR: There has been substantial interest in the use of actinide-bearing minerals, especially isometric pyrochlore, A 2 B 2 O 7 (A = rare earths; B = Ti, Zr, Sn, Hf), for the immobilization of actinsides, particularly plutonium, both as inert matrix fuels and nuclear waste forms.

TL;DR: In this article, the authors consider the problem of reinterpretation of the tomographie traditionnelle avec des ondes de surface, and propose an approach based on the possibilité d'extraire une information cohérente sur la propagation entre deux capteurs.