Recently added

ENVIRONMENTAL GEOCHEMISTRY OF CALCIUM ISOTOPES: APPLICATIONS OF A NEW STABLE ISOTOPE APPROACH

Liu Z.; Liu C.; Han G.; Wang Z.; Xue Z.; Song Z.; Yang C. (2006)

This paper summarizes isotope fractionation mechanism, analytical method and applications in environmental geochemistry of calcium isotopes. Calcium isotopic composition can be used to constrain material sources and study ...

KINETICS OF CATION ORDERING IN NATURAL MG(AL,CR3+)2 O4 SPINELS

Princivalle F.; Martignago F.; Dal Negro A. (2006)

The kinetics of cation ordering (quench method) in two natural Mg(Al2-yCry)O4 spinels (y~0.03-0.06 and 0.24), highly ordered in terms of Mg-Al, were studied by means of X-ray single-crystal diffraction. The equilibrium ...

PHOSPHATASE AND MICROBIAL ACTIVITY WITH BIOCHEMICAL INDICATORS IN SEMI-PERMAFROST ACTIVE LAYER SEDIMENTS OVER THE PAST 10,000 YEARS

Takano Y.; Marumo K.; Mori H.; Kaneko T.; Kobayashi K.; Ishikawa Y. (2006)

Core samples of boreal terrestrial sediments from depths of 0-300 cm at Rikubetsu, Hokkaido, Japan were analyzed for alkaline and acid phosphatase enzymatic activities. Enzymatic activities of alkaline phosphatase (ALP) ...

MOBILITY AND FRACTIONATION OF RARE EARTH ELEMENTS DURING SUPERGENE WEATHERING AND GOSSAN FORMATION AND CHEMICAL MODIFICATION OF MASSIVE SULFIDE GOSSAN

Leybourne M.I.; Peter J.M.; Boyle D.R.; Layton-Matthews D.; Volesky J. (2006)

Primary massive sulfide gossans (MSG) in the Bathurst Mining Camp (BMC), New Brunswick, Canada, are characterized by relative enrichment of Au, Sb, and As, formation of jarosite group minerals (jarosite, plumbojarosite, ...

DUAL SPECIATION OF NITROGEN IN SILICATE MELTS AT HIGH PRESSURE AND TEMPERATURE: AN EXPERIMENTAL STUDY

Roskosz M.; Mysen B.O.; Cody G.D. (2006)

Solubility and speciation of nitrogen in silicate melts have been investigated between 1400 and 1700 °C and at pressures ranging from 10 to 30 kbar for six different binary alkali and alkaline-earth silicate liquids and a ...

EPISODIC MINERALIZATION OF HYDROTHERMAL ILLITE IN THE SOULTZ-SOUS-FORêTS GRANITE (UPPER RHINE GRABEN, FRANCE)

Schleicher A.M.; Warr L.N.; Clauer N.; Kober B.; Laverret E. (2006)

Episodic and localized illite mineralization is documented in the hydrothermally altered Soultz-sous-Forêts granite (Upper Rhine Graben, France). Separated grain-size fractions of altered granite and argillite vein samples ...

THE SIZE DISTRIBUTION OF EXSOLUTION LAMELLAE IN IRON-FREE CLINOPYROXENE

Weinbruch S.; Styrsa V.; Dirsch T. (2006)

The size distribution of pigeonite and diopside exsolution lamellae on "001," obtained at temperatures of 1100, 1200, and 1300 °C and annealing times between 2 and 4320 h, was studied by transmission electron microscopy. ...

RIETVELD STRUCTURE REFINEMENT OF NH4-EXCHANGED NATURAL CHABAZITE

Gualtieri A.F.; Passaglia E. (2006)

In this work the results of the X-ray Rietveld structure refinement of a natural and the corresponding NH4-exchanged chabazite from Nova Scotia (Canada) are exposed. Experimental data were collected using a laboratory ...

MICROBIAL REDUCTION OF FE(III) IN THE FIFTHIAN AND MULOORINA ILLITES: CONTRASTING EXTENTS AND RATES OF BIOREDUCTION

Seabaugh J.L.; Dong H.; Morton J.P.; Kukkadapu R.K.; Eberl D.D.; Kim J. (2006)

Shewanella putrefaciens CN32 reduces Fe(III) within two illites which have different properties: the Fithian bulk fraction and the <0.2 μm fraction of Muloorina. The Fithian illite contained 4.6% (w/w) total Fe, 81% of ...

AN INTEGRATED APPROACH FOR DETERMINING THE ORIGIN OF MAGNETITE NANOPARTICLES

Faivre D.; Zuddas P. (2006)

The criteria to assess the origin of magnetite are of prime importance because of their significance as biomarkers for extraterrestrial life and paleoenvironmental indicators. It is still unclear if morphology and magnetic ...

TOWARDS AN ISOTOPIC MODELING OF THE ILLITIZATION PROCESS BASED ON DATA OF ILLITE-TYPE FUNDAMENTAL PARTICLES FROM MIXED-LAYER ILLITE-SMECTITE

Clauer N. (2006)

Burial-induced and hydrothermal-related illitization in bentonites and in sandstones can be modeled on the basis of isotopic studies of fundamental particles separated from mixed-layer illite-smectite. The model envisages ...

TRACING NITROGEN IN VOLCANIC AND GEOTHERMAL VOLATILES FROM THE NICARAGUAN VOLCANIC FRONT

Elkins L.J.; Fischer T.P.; Sharp Z.D.; Hilton D.R.; McKnight S.; Walker J. (2006)

We report new chemical and isotopic data from 26 volcanic and geothermal gases, vapor condensates, and thermal water samples, collected along the Nicaraguan volcanic front. The samples were analyzed for chemical abundances ...

MODELS OF OXIC RESPIRATION, DENITRIFICATION AND SULFATE REDUCTION IN ZONES OF COASTAL UPWELLING

Canfield D.E. (2006)

Coastal upwelling zones support some of the highest rates of primary production in the oceans. The settling and subsequent decomposition of this organic matter promotes oxygen depletion. In the Eastern tropical North and ...

EXAFS SIGNATURE OF STRUCTURAL ZN AT TRACE LEVELS IN NATURAL AND SYNTHETIC TRIOCTAHEDRAL 2:1 PHYLLOSILICATES

Juillot F.; Morin G.; Ildefonse P.; Calas G.; Brown Jr G.E. (2006)

EXAFS spectroscopy has been used to determine the medium-range structural environment (within a radius of ≈7 Å) of trace levels of Zn2+ ions within the octahedral sheets of trioctahedral 2:1 phyllosilicates. EXAFS signatures ...

GENESIS AND COMPOSITIONAL HETEROGENEITY OF SMECTITES. PART III: ALTERATION OF BASIC PYROCLASTIC ROCKS - A CASE STUDY FROM THE TROODOS OPHIOLITE COMPLEX, CYPRUS

Christidis G.E. (2006)

Upper Cretaceous basic pyroclastic rocks, which overlie the Upper Pillow Lavas of the Troodos ophiolitic complex, Cyprus have been altered to bentonites. The resulting smectite is Fe-rich montmorillonite and Fe-rich ...

PALEO-OCEAN CHEMISTRY RECORDS IN MARINE OPAL: IMPLICATIONS FOR FLUXES OF TRACE ELEMENTS, COSMOGENIC NUCLIDES (10BE AND 26AL), AND BIOLOGICAL PRODUCTIVITY

Lal D.; Charles C.; Vacher L.; Goswami J.N.; Jull A.J.T.; McHargue L.; Finkel R.C. (2006)

Here, we provide evidence suggesting that marine (diatom) opal contains not only a high fidelity record of dissolved oceanic concentrations of cosmic ray-produced radionuclides, 10Be and 26Al, but also a record of temporal ...

SEMI-BRITTLE FLOW DURING DEHYDRATION OF LIZARDITE-CHRYSOTILE SERPENTINITE DEFORMED IN TORSION: IMPLICATIONS FOR THE RHEOLOGY OF OCEANIC LITHOSPHERE

Hirose T.; Bystricky M.; Kunze K.; Stünitz H. (2006)

Serpentinite is a significant component of the oceanic lithosphere and plays an important role in subduction dynamics. However, the rheology of serpentine-bearing rocks is poorly understood, especially at large strains and ...

LAYERED MANTLE STRUCTURE BENEATH THE WESTERN GUYANA SHIELD, VENEZUELA: EVIDENCE FROM DIAMONDS AND XENOCRYSTS IN GUANIAMO KIMBERLITES

Schulze D.J.; Canil D.; Channer D.M.De.R.; Kaminsky F.V. (2006)

Mantle xenoliths and xenocrysts from Guaniamo, Venezuela kimberlites record equilibration conditions corresponding to a limited range of sampling in the lithosphere (100-150 km). Within this small range, however, compositions ...

HOLOCENE CENTENNIAL TO MILLENNIAL-SCALE CLIMATIC VARIABILITY: EVIDENCE FROM HIGH-RESOLUTION MAGNETIC ANALYSES OF THE LAST 10 CAL KYR OFF NORTH ICELAND (CORE MD99-2275)

Rousse S.; Kissel C.; Laj C.; Eiríksson J.; Knudsen K.-L. (2006)

High-resolution magnetic analysis has been performed on the top ~25 m of core MD99-2275 (66°33.06′N, 17°41.59′W; 440 m water depth) from the mid-outer shelf off North Iceland. This is a key boundary region for climate ...

SLIP SYSTEMS AND PLASTIC SHEAR ANISOTROPY IN MG2SIO4 RINGWOODITE: INSIGHTS FROM NUMERICAL MODELLING

Carrez P.; Cordier P.; Mainprice D.; Tommasi A. (2006)

Knowledge on the deformation mechanisms of Mg2SiO4 ringwoodite is important for the understanding of flow and seismic anisotropy in the Earth's mantle transition zone. We report here the first numerical modelling of ...

Recently added

GeologyScience Repository: Recent submissions

Search DSpace

Browse

All of DSpace

My Account