Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience
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Surface-water iron supplies in the Southern Ocean sustained by deep winter mixing

Surface-water iron supplies in the Southern Ocean sustained by deep winter mixing | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Low levels of iron limit primary productivity across much of the Southern Ocean. Measurements of dissolved iron levels combined with hydrographic data suggest that much of the iron in the surface waters of the Southern Ocean is supplied by deep mixing during winter.
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The authors have analysed data on dissolved iron concentrations in the top 1,000 m of the Southern Ocean, taken from all known and available cruises to date, together with hydrographic data to determine the relative importance of deep winter mixing and diapycnal diffusion to dissolved iron fluxes at the basin scale. They concluded that winter mixing and surface-water iron recycling are important drivers of temporal variations in Southern Ocean primary production.

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Green synthesis of pyrite nanoparticles for energy conversion and storage: a spectroscopic investigation

Green synthesis of pyrite nanoparticles for energy conversion and storage: a spectroscopic investigation | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Pyrite, FeS2, nanoparticles were obtained through a one-pot solvothermal synthesis, without surfactants, carried out at room pressure and mild temperature (~180°C).
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Hydrogenation of iron in the early stage of Earth’s evolution

Hydrogenation of iron in the early stage of Earth’s evolution | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors carried out high-pressure and high-temperature in situ neutron diffraction experiments and clarify that when the mixture of iron and hydrous minerals are heated, iron is hydrogenized soon after the hydrous mineral is dehydrated.
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Formation of amorphous calcium carbonate in caves and its implications for speleothem research

Formation of amorphous calcium carbonate in caves and its implications for speleothem research | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
An innovative sampling and measurement protocol combined with scanning and transmission electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy is presented, demonstrating that carbonate precipitating from drip water in caves at ~10 °C contains amorphous calcium carbonate (ACC) that later transforms to nanocrystalline calcite.
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Selection and Use of Manganese Dioxide by Neanderthals

Selection and Use of Manganese Dioxide by Neanderthals | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Several Mousterian sites in France have yielded large numbers of small black blocs.
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Compositional analyses lead the authors to infer that late Neanderthals at Pech-de-l’Azé I were deliberately selecting manganese dioxide.
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Silicate mineralogy at the surface of Mercury

Silicate mineralogy at the surface of Mercury | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Near-infrared to ultraviolet spectra and images have provided evidence for the Fe2+-poor nature of silicate minerals, magnesium sulfide minerals in hollows and a darkening component attributed to graphite, but existing spectral data is insufficient to build a mineralogical map for the planet.
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An overview of the platinum-group element nanoparticles in mantle-hosted chromite deposits

An overview of the platinum-group element nanoparticles in mantle-hosted chromite deposits | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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This paper reviews the occurrence of platinum-group elements nanoparticles (PGE-NPs) in mantle-hosted chromite deposits, showing that PGE-NPs are more frequently found in these deposits than previously thought.
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Competitive fitness of a predominant pelagic calcifier impaired by ocean acidification

Competitive fitness of a predominant pelagic calcifier impaired by ocean acidification | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors report on a mesocosm experiment conducted in a Norwegian fjord in which we exposed a natural plankton community to a wide range of CO2-induced ocean acidification, to test whether these physiological responses affect the ecological success of coccolithophore populations.
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Study of the Interaction of Eu3+ with Microbiologically Induced Calcium Carbonate Precipitates using TRLFS

Study of the Interaction of Eu3+ with Microbiologically Induced Calcium Carbonate Precipitates using TRLFS | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
The microbial induced biomineralization of calcium carbonate using the ureolytic bacterium Sporosarcina pasteurii in the presence of trivalent europium, a substitute for trivalent actinides, was investigated by time-resolved laser-induced fluorescence spectroscopy (TRLFS) and a variety of physicochemical techniques.
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Arsenic incorporation in pyrite at ambient temperature at both tetrahedral S-I and octahedral Fe+II sites

Arsenic incorporation in pyrite at ambient temperature at both tetrahedral S-I and octahedral Fe+II sites | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it


Pyrite is an ubiquitous mineral in reducing environments, and is well-known to incorporate trace elements such as Co, Ni, Se, Au and commonly arsenic. Indeed, As-bearing pyrite is observed in a wide variety of sedimentary environments, making it a major sink for this toxic metalloid.
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Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults

Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
The criteria for designating an “Active Fault” not only are important for understanding regional tectonics, but also are a paramount issue for assessing the earthquake risk of faults that are near important structures such as nuclear power plants.
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X-ray diffraction data and electron microscope observations of samples from an active fault demonstrated the preservation of large amounts of amorphous ultrafine particles in two slip zones that last ruptured in 1596 and 1999, respectively.
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Ancient rocks hold evidence for life before oxygen

Ancient rocks hold evidence for life before oxygen | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
UC geologist uncovers 2.5 billion-year-old fossils of bacteria that predate the formation of oxygen.
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Scandium speciation in a world-class lateritic deposit

Scandium speciation in a world-class lateritic deposit | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Geochemical Perspectives Letters is a new journal of the European Association of Geochemistry.
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At microscopic and atomic scales, by combining X-ray absorption near-edge structure spectroscopy, X-ray diffraction and microscopic and chemical analyses, the authors show that Sc-rich volumes are associated with iron oxides. In particular, Sc adsorbed on goethite accounts for ca. 80 % of the Sc budget in the samples. The remaining Sc is incorporated in the crystal structure of haematite, substituting for Fe3+.
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Smudged volcanic crystals offer clues to past eruptions

Smudged volcanic crystals offer clues to past eruptions | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
How diffusion clocks are revealing the histories and personalities of hibernating volcanoes
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Early formation of the Moon 4.51 billion years ago

Early formation of the Moon 4.51 billion years ago | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Establishing the age of the Moon is critical to understanding solar system evolution and the formation of rocky planets, including Earth. However, despite its importance, the age of the Moon has never been accurately determined. We present uranium-lead dating of Apollo 14 zircon fragments that yield highly precise, concordant ages, demonstrating that they are robust against postcrystallization isotopic disturbances. Hafnium isotopic analyses of the same fragments show extremely low initial 176Hf/177Hf ratios corrected for cosmic ray exposure that are near the solar system initial value. Our data indicate differentiation of the lunar crust by 4.51 billion years, indicating the formation of the Moon within the first ~60 million years after the birth of the solar system.
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Heterogeneity in mantle carbon content from CO2-undersaturated basalts

Heterogeneity in mantle carbon content from CO2-undersaturated basalts | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors used the correlations of CO2 with trace elements to define an average carbon abundance for the upper mantle.
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Formation of carbonate chimneys in the Mediterranean Sea

Formation of carbonate chimneys in the Mediterranean Sea | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors have characterized rocks sampled from metre-size build-ups of methane-derived carbonate chimneys located at the Amon mud volcano on the Nile deep-sea fan.
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Environmental controls on biomineralization and Fe-mound formation in a low-temperature hydrothermal system at the Jan Mayen Vent Fields

Environmental controls on biomineralization and Fe-mound formation in a low-temperature hydrothermal system at the Jan Mayen Vent Fields | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors conducted 16S rRNA gene analyses, microscopy and geochemical analyses of laminated siliceous Fe-mounds from the Jan Mayen Vent Fields at the Arctic Mid-Ocean Ridge.
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FIRST DETECTION OF BORON ON THE SURFACE OF MARS|FIRST SIGNS OF GROUNDWATER ON MARS

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Arsenic in hydrothermal apatite: Oxidation state, mechanism of uptake, and comparison between experiments and nature

Arsenic in hydrothermal apatite: Oxidation state, mechanism of uptake, and comparison between experiments and nature | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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X-ray Absorption Near-edge Spectroscopy (XANES) data show that As retained the trivalent oxidation state in the fully-reacted apatite grown from solutions containing only As(III). Extended X-ray Fine Spectroscopy (EXAFS) data reveal that these As(III) ions are surrounded by about three oxygen atoms at an As-O bond length close to that of an arsenate group (AsO43−), indicating that they occupy tetrahedral phosphate sites. The three-coordinated As(III)–O3 structure, with three oxygen atoms and one lone electron pair around As(III), was confirmed by geometry optimization using ab initio molecular simulations.
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Replacement of Calcite (CaCO3) by Cerussite (PbCO3)

Replacement of Calcite (CaCO3) by Cerussite (PbCO3) | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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the authors report a study of the bulk transformation of single-crystal calcite (CaCO3) into polycrystalline cerussite (PbCO3) through reaction with acidic Pb-bearing solutions.
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Time-Resolved in Situ Raman Spectroscopy of the Nucleation and Growth of Siderite, Magnesite, and Calcite

Time-Resolved in Situ Raman Spectroscopy of the Nucleation and Growth of Siderite, Magnesite, and Calcite | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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As expected, siderite and calcite can rapidly form via an amorphous precursor when using concentrated solutions of reactants directly mixed at ambient temperature (∼25 °C) and pressure (∼1 bar) (i.e., via spinodal decomposition or when energetic barrier is close to zero).
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Collisions in outer space produced an icosahedral phase in the Khatyrka meteorite never observed previously in the laboratory

Collisions in outer space produced an icosahedral phase in the Khatyrka meteorite never observed previously in the laboratory | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
We report the first occurrence of an icosahedral quasicrystal with composition Al62.0(8)Cu31.2(8)Fe6.8(4), outside the measured equilibrium stability field at standard pressure of the previously reported Al-Cu-Fe quasicrystal (AlxCuyFez, with x between 61 and 64, y between 24 and 26, z between 12 and 13%).
Ath Godelitsas's insight:
The new icosahedral mineral formed naturally and was discovered in the Khatyrka meteorite, a recently described CV3 carbonaceous chondrite that experienced shock metamorphism, local melting (with conditions exceeding 5 GPa and 1,200 °C in some locations), and rapid cooling, all of which likely resulted from impact-induced shock in space.
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An urban collection of modern-day large micrometeorites

An urban collection of modern-day large micrometeorites | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors report the discovery of significant numbers (500) of large micrometeorites (>100 μm) from rooftops in urban areas. The identification of particles as micrometeorites is achieved on the basis of their compositions, mineralogies, and textures.
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Evidence for an early wet Moon from experimental crystallization of the lunar magma ocean

Evidence for an early wet Moon from experimental crystallization of the lunar magma ocean | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
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The authors performed a high-pressure, high-temperature experimental study of lunar mineralogical and geochemical evolution during magma ocean solidification that yields constraints on the presence of water in the earliest lunar interior.
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Modified bacterial enzyme taught to make bonds that evolution avoids - bringing silicon to life!

Modified bacterial enzyme taught to make bonds that evolution avoids - bringing silicon to life! | Mineralogy, Geochemistry, Mineral Surfaces & Nanogeoscience | Scoop.it
Organic compounds containing silicon are important for a number of applications, from polymers to semiconductors. The catalysts used for creating carbon-silicon bonds, however, often require expensive trace metals or have limited lifetimes. Borrowing from the ability of some metallo-enzymes to catalyze other rare carbene insertion reactions, Kan et al. used heme proteins to form carbon-silicon bonds across a range of conditions and substrates (see the Perspective by Klare and Oestreich). Directed evolution experiments using cytochrome c from Rhodothermus marinus improved the reaction to be 15 times more efficient than industrial catalysts.

Science , this issue p. [1048][1]; see also p. [970][2]

[1]: /lookup/doi/10.1126/science.aah6219
[2]: /lookup/doi/10.1126/science.aal1951
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