The authors report evidence for ancient life from a newly exposed outcrop of 3,700-Myr-old metacarbonate rocks in the ISB that contain 1–4-cm-high stromatolites—macroscopically layered structures produced by microbial communities.
This observation suggests that during the accretion of the Earth, nebular H2 could have been delivered to the growing solid planet by direct dissolution in a magma ocean and subsequent incorporation in silicates.
Atmospheric water vapour interacting with hydrophilic mineral surfaces can produce water films of various thicknesses and structures.
Ath Godelitsas's insight:
Water adsorption isotherms were predicted using models (1- or 2- term Freundlich and Do-Do models) describing an adsorption and a condensation regime, respectively pertaining to the binding of water onto mineral surfaces and water film growth by water-water interactions.
This study reports the first detailed geochemical characterization of Kolumbo submarine volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt.% SiO2, 4.2 wt.% K2O). Lava bodies exposed in the crater and enclaves are basalts to andesites (52–60 wt.% SiO2). Biotite and amphibole are common phenocryst phases, in contrast with the typically anhydrous mineral assemblages of Santorini. The strong geochemical signature of amphibole fractionation and the assimilation of lower crustal basement in the petrogenesis of the Kolumbo magmas indicates that Kolumbo and Santorini underwent different crustal differentiation histories and that their crustal magmatic systems are unrelated. Moreover, the Kolumbo samples are derived from a distinct, more enriched mantle source that is characterized by high Nb/Yb (>3) and low 206Pb/204Pb (<18.82) that has not been recognized in the Santorini volcanic products. The strong dissimilarity in both petrogenesis and inferred mantle sources between Kolumbo and Santorini suggests that pronounced source variations can be manifested in arc magmas that are closely associated in space and time within a single volcanic field.
Synchrotron radiation techniques (μ-XRF and μ-XANES) were applied to the study of organic-rich phosphatized limestones of NW Greece (Epirus). The results revealed uranium accumulation in areas of the material containing, among others, carbonate apatite (francolite) and organic matter. The UL3-edge of μ-XANES spectra showed that uranium was present in tetravalent form. U-bearing francolite crystals were separated from the rock and characterized by Raman spectroscopy and microprobe. The analysis of the crystals also indicated the presence of sodium and sulfur. The uranium presence in the crystals was also visualized, after neutron irradiation and etching, by the observation of the fission tracks.
The authors used coated-wall flow tube measurements of NO2 reactivity on environmentally relevant surfaces (Fe (hydr)oxides, clay minerals, and soil from Arizona and the Saharan Desert) and detailed mineralogical characterization of substrates to show that reduction of NO2 by Fe-bearing minerals in soil can be a more important source of HONO than the putative NO2 hydrolysis mechanism.
Recent advances in lab-based and synchrotron radiation–based X-ray computed microtomography and nanotomography have made it possible to visualize and quantify rock volumes in a 3-D space. In this study, the authors analyzed microscale textures in oriented drill cores from the world-class Suurikuusikko orogenic gold deposit of northern Finland using lab-based X-ray computed microtomography.
Combining spectral data with high-resolution images, the authors map a large (10 km × 5 km) alunite-bearing deposit in southwest Cross crater, widespread kaolin-bearing sediments with variable amounts of alunite that are layered in <10 m scale beds, and silica- and/or montmorillonite-bearing deposits that occupy topographically lower, heavily fractured units.
Here ultrafast nonlinear infrared (IR) techniques, two-dimensional infrared (2D IR) and polarization selective pump–probe (PSPP) spectroscopies, were used to measure the dynamics and disorder of water of hydration in two minerals, gypsum (CaSO4·2H2O) and bassanite (CaSO4·0.5H2O).
Over the last hundred years, about 150 000 of inorganic crystal structures have been elucidated and visualized. In this review the author uses information theory to characterize complexity of inorganic structures in terms of their information content.
Hydrometallurgical processing of chalcopyrite is hindered predominantly due to the passivation layers formed on the chalcopyrite surface. However, the effects of impurity cations released from the gangue are not yet well understood. Density functional theory (DFT) calculations were carried out to investigate monovalent cations of Na+ and K+ on chalcopyrite (001)-S surface using Materials Studio. The results show that the 3d orbital of Fe and 3p orbital of S predominantly contribute to their activities during chalcopyrite oxidation and dissolution processes. In addition, SO42− is more likely to be adsorbed on one Fe site in the presence of Na+, while it is preferentially adsorbed on two Fe sites in the presence of K+. However, the adsorption of both Na2SO4 and K2SO4 on the chalcopyrite (001)-S surface contributes to the breakage of S–S bonds, indicating that the impurity cations of Na+ and K+ are beneficial to chalcopyrite leaching in a sulfuric environment. The adsorption energy and partial density of states (PDOS) analyses further indicate that the adsorption of Na2SO4 on chalcopyrite (001)-S surface is favored in both -BB (bidentate binuclear ) and -BM (bidentate mononuclear) modes, compared to the adsorption of K2SO4.
High-temperature condensates found in meteorites display uranium isotopic variations (235U/238U), which complicate dating the solar system’s formation and whose origin remains mysterious. It is possible that these variations are due to the decay of the short-lived radionuclide 247Cm ( t 1/2 = 15.6 My) into 235U, but they could also be due to uranium kinetic isotopic fractionation during condensation. We report uranium isotope measurements of meteoritic refractory inclusions that reveal excesses of 235U reaching ~+6% relative to average solar system composition, which can only be due to the decay of 247Cm. This allows us to constrain the 247Cm/235U ratio at solar system formation to (1.1 ± 0.3) × 10−4. This value provides new clues on the universality of the nucleosynthetic r -process of rapid neutron capture.
The delamination of montmorillonite in water leads to sliming in ore slurry, which is detrimental to mineral flotation and solid/water separation. In this work, the delamination of Na-montmorillonite (Na-MMT) has been restrained by sodium dodecyl sulfate (SDS) or octadecyl trimethyl ammonium chloride (1831) through the adsorption on the edge of the mineral. The experimental results have shown that the pretreatment by adding SDS and 1831 could greatly reduce the Stokes size percentage of −1.1 µm particles in the aqueous Na-MMT suspension. From the X-ray diffractometer (XRD) results, the interlayer spacing of the MMT pre-treated by SDS and 1831 is smaller than that of original MMT particles. Adsorption position of SDS and 1831 on MMT surfaces was analyzed by the measurements of adsorption capacity of SDS and 1831, inductively-coupled plasma spectra, and zeta potential before and after the plane surface of MMT was covered with tetraethylenepentaminecopper ([Cu(tetren)]2+). The results indicated that SDS and 1831 are adsorbed on the edge and the whole surface of Na-MMT, respectively. Delamination of MMT could be well restrained by the adsorption of SDS and 1831 on the edges of MMT.
Metal-organic frameworks (MOFs) are an increasingly important family of advanced materials based on open, nanometer-scale metal-organic architectures, whose design and synthesis are based on the directed assembly of carefully designed subunits. We now demonstrate an unexpected link between mineralogy and MOF chemistry by discovering that the rare organic minerals stepanovite and zhemchuzhnikovite exhibit structures found in well-established magnetic and proton-conducting metal oxalate MOFs. Structures of stepanovite and zhemchuzhnikovite, exhibiting almost nanometer-wide and guest-filled apertures and channels, respectively, change the perspective of MOFs as exclusively artificial materials and represent, so far, unique examples of open framework architectures in organic minerals.
A well-dated sedimentary sequence from the ancient harbor of Naples sheds new light on an old problem: could the great AD 79 Vesuvius eruption have affected the water supply of the cities around the Bay of Naples? The authors here show, using Pb isotopes, that this volcanic catastrophe not only destroyed the urban lead pipe water supply network, but that it took the Roman administration several decades to replace it, and that the commissioning of the new system, once built, occurred nearly instantaneously. Moreover, discontinuities in the Pb isotopic record of the harbor deposits prove a powerful tool for tracking both Naples’ urbanization and later major conflicts at the end of the Roman period and in early Byzantine times.
The authors used pair distribution function (PDF) analysis to provide evidence that the local structure of ACC gradually changes as the pH of the synthesis solutions is increased from 10.6 to 12.7, at ambient conditions.
Sharing your scoops to your social media accounts is a must to distribute your curated content. Not only will it drive traffic and leads through your content, but it will help show your expertise with your followers.
How to integrate my topics' content to my website?
Integrating your curated content to your website or blog will allow you to increase your website visitors’ engagement, boost SEO and acquire new visitors. By redirecting your social media traffic to your website, Scoop.it will also help you generate more qualified traffic and leads from your curation work.
Distributing your curated content through a newsletter is a great way to nurture and engage your email subscribers will developing your traffic and visibility.
Creating engaging newsletters with your curated content is really easy.