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Historical records of mercury, lead, and PAH depositions in a dated sediment core from the eastern Mediterranean

Historical records of mercury, lead, and PAH depositions in a dated sediment core from the eastern Mediterranean | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Depth profiles of mercury, lead and its stable isotopes, and polycyclic aromatic hydrocarbons were determined in a dated sediment core from the Levantine basin. Sedimentary records show that preindustrial fluxes and levels of Hg, Pb, and PAHs remained generally constant in the region before 1850. An almost concurrent uniform increase of both metals and PAHs deposition occurring at the beginning of the Industrial Revolution suggests coal combustion as a main source of these contaminants in the Levantine basin after the 1850s. However, none of the contaminant profiles indicates a decline after 1950–60, the characteristic period of coal use reduction.

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Incorporation of Pb at the Calcite-Water Interface

Incorporation of Pb at the Calcite-Water Interface | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Using in situ specular and resonant anomalous X-ray reflectivity measurements, the authors investigated the interaction of the calcite (104) surface with a dilute Pb- and EDTA-bearing solution that is slightly undersaturated with respect to calcite. The X-ray results reveal Pb coherently substituting for Ca in the near-surface layers of strained calcite with Pb/(Pb + Ca) atom fractions as high as 0.28 in the outermost layer. The larger ionic radius of Pb2+ relative to Ca2+ is accommodated in calcite by vertical displacements of Pb relative to the Ca site. In situ atomic force microscopy images obtained during the reaction suggest that Pb incorporation below the surface occurs after initial dissolution followed by regrowth of a strained epitaxial Pb-rich calcite solid-solution at the calcite (104)–water interface.

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Selenium Speciation in Framboidal and Euhedral Pyrites in Shales

Selenium Speciation in Framboidal and Euhedral Pyrites in Shales | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The authors combined bulk characterization, sequential extractions, and spatially resolved μ-focus spectroscopic analyses and investigated the occurrence and distribution of Se and other associated elements (Fe, As, Cr, Ni, and Zn) and determined the Se speciation at the μ-scale in typical, low bulk Se containing shales.

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Arsenic Sorption in Iron and Manganese Binary Oxide

Arsenic Sorption in Iron and Manganese Binary Oxide | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The respective role of Fe and Mn contents present in the Fe–Mn binary oxide on As(III) removal was investigated via a direct in situ determination of arsenic speciation using X-ray absorption spectroscopy.

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Nucleation and growth of todorokite from birnessite in marine sediments

Nucleation and growth of todorokite from birnessite in marine sediments | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

The authors transformed a synthetic, poorly crystalline, hexagonal birnessite, analogous to marine birnessite, into todorokite under a mild reflux procedure, developed to mimic marine diagenesis and mild hydrothermal conditions. They characterized birnessite and reflux products as a time series, employing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), BET surface area analysis, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and extended X-ray absorption fine structure spectroscopy (EXAFS).

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Hundreds of Methane Plumes Erupting Along East Coast

Hundreds of Methane Plumes Erupting Along East Coast | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Hundreds of methane gas plumes bubbling up from the seabed were spotted during an extensive seafloor survey along the U.S. Atlantic Coast.
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Cobalt incorporation in calcite

Cobalt incorporation in calcite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The thermodynamics of (Ca,Co)CO3 solid solutions are still unclear due to conflicting data from experiment and from the observation of natural occurrences. The authors report here the results of a computer simulation study of the mixing of calcite (CaCO3) and spherocobaltite (CoCO3), using density functional theory calculations.

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Mineral magic? Common mineral capable of making, breaking bonds

Mineral magic? Common mineral capable of making, breaking bonds | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

Reactions among minerals and organic compounds in hydrothermal environments are critical components of the Earth’s deep carbon cycle.

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The ASU team set out to understand how different minerals affect hydrothermal organic reactions and found that a common sulfide mineral (ZnS, or Sphalerite) cleanly catalyzes a fundamental chemical reaction: the making and breaking of a C-H bond.

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ZEISS Mineralogic-Mining: a new automated mineralogy system on the market

ZEISS Mineralogic-Mining:  a new automated mineralogy system on the market | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

This week, ZEISS released the latest automated mineralogy system to hit the market; Mineralogic-Mining.  Mineralogic-Mining combines a scanning electron microscope with one or more EDS detectors

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Los Alamos, Toshiba probing Fukushima with cosmic rays

Los Alamos National Laboratory has announced an impending partnership with Toshiba Corporation to use a Los Alamos technique called muon tomography to safely peer inside the cores of the Fukushima Daiichi reactors and create high-resolution images of the damaged nuclear material inside without ever breaching the cores themselves. The initiative could reduce the time required to clean up the disabled complex by at least a decade and greatly reduce radiation exposure to personnel working at the plant. Muon radiography (also called cosmic-ray radiography) uses secondary particles generated when cosmic rays collide with upper regions of Earth's atmosphere to create images of the objects that the particles, called muons, penetrate. The process is analogous to an X-ray image, except muons are produced naturally and do not damage the materials they contact. Muon radiography has been used before in imaginative applications such as mapping the interior of the Great Pyramid at Giza, but Los Alamos's muon tomography technique represents a vast improvement over earlier technology.

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Hf-Nd isotopic variability in mineral dust from Chinese and Mongolian deserts

Hf-Nd isotopic variability in mineral dust from Chinese and Mongolian deserts | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors report the clay-sized (<2 μm) Hf-Nd isotope data from Asian dust sources to better constrain the source and transport dynamics of dust deposition in the North Pacific.

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Nature Milestones in Crystallography

Nature Milestones in Crystallography | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Nature Milestones in Crystallography, a collaborative effort between Nature, Nature Materials, Nature Nanotechnology and Nature Structural & Molecular Biology, is the eleventh supplement in the series and is timed to coincide with the celebration of the 2014 International Year of Crystallography. Exactly 100 years ago, Max von Laue received the Nobel Prize in Physics “for his discovery of the diffraction of X-rays by crystals”. Since that discovery, crystallography has become an essential tool of investigation throughout the sciences, largely because it provides conclusive information on molecular structure down to the atomic level.

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Martian Rock and Dust Filling Studied with Laser and Camera - Mars Science Laboratory

Martian Rock and Dust Filling Studied with Laser and Camera - Mars Science Laboratory | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Scientists used the ChemCam instrument on NASA's Curiosity Mars rover to examine a Martian rock "shell" about one inch across, embedded in bedrock and with a hollow interior. This graphic combines an image of the target with results from using ChemCam's laser on the rock and adjacent points
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Ramp compression of diamond to five terapascals

Ramp compression of diamond to five terapascals | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Recent developments in shock-free dynamic (ramp) compression now allow laboratory access to this dense matter regime. Here we describe ramp-compression measurements for diamond, achieving 3.7-fold compression at a peak pressure of 5 terapascals (equivalent to 50 million atmospheres). These equation-of-state data can now be compared to first-principles density functionalcalculations and theories long used to describe matter present in the interiors of giant planets, in stars, and in inertial-confinement fusion experiments. Our data also provide new constraints on mass–radius relationships for carbon-rich planets.

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Plutonium(V) Reduction on Hematite

Plutonium(V) Reduction on Hematite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Surface-mediated reduction of Pu(V) was observed under all conditions studied. However, differences in the reaction kinetics demonstrate that the mechanism of Pu(V) reduction changes as a function of plutonium concentration. Adsorption of Pu(V) was found to be the rate-limiting step at plutonium concentrations less than approximately 10–7 M Pu(V). Plutonium reduction in these systems was attributed to trace amounts of Fe(II) in the hematite structure. Reduction of Pu(V) was found to be the rate-limiting step at concentrations higher than approximately 10–6 M Pu(V) and is attributed to the formation of PuO2+x·nH2O nanoparticles and the Nernstian favorability of Pu(IV) surface complexes.

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Geochemical Control on Uranium(IV) Mobility in a Mining-Impacted Wetland

Geochemical Control on Uranium(IV) Mobility in a Mining-Impacted Wetland | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The speciation of U at a location not impacted by the clay-rich layer is a different noncrystalline U(IV) species, consisting of U(IV) bound to organic matter in soil. Also, the clay-poor location includes an abundant sulfate supply and active microbial sulfate reduction that induce substantial pyrite (FeS2) precipitation.

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Arsenic speciation in natural sulfidic geothermal waters

Arsenic speciation in natural sulfidic geothermal waters | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

See also: http://www.sciencedirect.com/science/article/pii/S0039914014003130

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The speciation of arsenic in natural sulfidic geothermal waters was studied using chemical analyses and thermodynamic aqueous speciation calculations.

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Sulfidization of Lepidocrocite and its Effect on Uranium Phase Distribution and Reduction

Sulfidization of Lepidocrocite and its Effect on Uranium Phase Distribution and Reduction | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors investigated the phase distribution and redox state of uranium in batch experiments, in which lepidocrocite with adsorbed U(VI) was reacted with sulfide.

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Job opportunities « European Association of Geochemistry

Job opportunities « European Association of Geochemistry | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
The European Association of Geochemistry, EAG, aims to promote geochemical research in Europe. (Job alert: Postdoctoral Research Scholar in Geochemistry @ucmerced.
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Seven grains of interstellar dust reveal their secrets

Seven grains of interstellar dust reveal their secrets | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it

The dust particle called Hylabrook contained the crystalline mineral olivine (pink), an amorphous material containing magnesium, and iron (green). Credit: Westphal et al. 2014, Science/AAAS - See more at: http://newscenter.lbl.gov/2014/08/14/mysteries-of-space-dust-revealed/#sthash.hbniP9P1.dpuf

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See also: http://newscenter.lbl.gov/2014/08/14/mysteries-of-space-dust-revealed/

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Minerals at the Nanoscale

Minerals at the Nanoscale | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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Saharan dust is key to formation of Bahamas' Great Bank, study finds

Saharan dust is key to formation of Bahamas' Great Bank, study finds | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Saharan dust played a major role in the formation of the Bahamas islands, a new study suggests. Researchers showed that iron-rich Saharan dust provides the nutrients necessary for specialized bacteria to produce the island chain's carbonate-based foundation. Persistent winds across Africa's 3.5-million square mile Sahara Desert lifts mineral-rich sand into the atmosphere where it travels the nearly 5,000-mile northwest journey towards the U.S. and Caribbean.
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See also "The fertilization of the Bahamas by Saharan dust: A trigger for carbonate precipitation?" by Swart et al.: http://geology.gsapubs.org/content/42/8/671

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Clinopyroxene precursors to amphibole sponge in arc crust

Clinopyroxene precursors to amphibole sponge in arc crust | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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This study provides evidence that amphibole develops by evolved melts overprinting earlier clinopyroxene—a near-ubiquitous mineral in arc magmas. Reaction-replacement of clinopyroxene ultimately forms granoblastic amphibole lithologies. Reaction-replacement amphiboles have more primitive trace element chemistry (for example, lower concentrations of incompatible Pb) than amphibole phenocrysts, but still have chemistries suitable for producing La/Yb and Dy/Yb ‘amphibole sponge’ signatures.

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Zircons reveal magma fluxes in the Earth's crust

Zircons reveal magma fluxes in the Earth's crust | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

The authors show that age distributions of zircons, a mineral often present in crustal magmatic rocks in combination with thermal modelling, provide an accurate means of retrieving magma fluxes. The characteristics of zircon age populations vary significantly and systematically as a function of the flux and total volume of magma accumulated in the Earth’s crust.

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Occurrence of Cr(VI) in drinking water of Greece and relation to the geological background

Occurrence of Cr(VI) in drinking water of Greece and relation to the geological background | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Ath Godelitsas's insight:

Higher Cr(VI) values are observed in aquifers in alluvial and neogene sediments of serpentine and amphibolite, originating from the erosion of ophiolithic and metamorphic rocks. In contrast, Cr(VI) concentration in samples from ophiolithic and metamorphic rocks was always below 10 μg/L due to both low contact time and surface area, as verified by low conductivity and salt concentration values. These findings indicate that under specific conditions, pollution of water by Cr(VI) is favorable by a slow MnO2-catalyzed oxidation of soluble Cr(III) to Cr(VI) in which manganese products [Mn(III)/Mn(II)] are probably re-oxidized by oxygen.

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Blogs | University of Nottingham-British Geological Survey Centre for Environmental Geochemistry

Blogs | University of Nottingham-British Geological Survey Centre for Environmental Geochemistry | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
University of Nottingham-British Geological Survey Centre for Environmental Geochemistry (RT @MelJLeng: Some new blogs from the @BritGeoSurvey @UniofNottingham Centre for Environmental Geochemistry http://t.co/lvRr955181)...
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