| People | Locations | Statistics |
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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Kononenko, Denys |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Muller, Hermance |
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| Kočí, Jan | Prague |
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| Šuljagić, Marija |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ospanova, Alyiya |
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| Blanpain, Bart |
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| Ali, M. A. |
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| Popa, V. |
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| Rančić, M. |
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| Ollier, Nadège |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Dyar, M. Darby
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (5/5 displayed)
- 2023Wave vector and field vector orientation dependence of Fe <i>K</i> pre-edge X-ray absorption features in clinopyroxenescitations
- 2023Fe(III) (oxyhydr)oxide reduction by the thermophilic iron-reducing bacterium Desulfovulcanus ferrireducenscitations
- 2012Carbonate precipitation under bulk acidic conditions as a potential biosignature for searching life on Marscitations
- 2011Methods to analyze metastable and microparticulate hydrated and hydrous iron sulfate mineralscitations
- 2009Effect of SiO2, total FeO, Fe3+/Fe2+ and alkali elements in basaltic glasses on mid-infrared spectracitations
Places of action
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article
Methods to analyze metastable and microparticulate hydrated and hydrous iron sulfate minerals
Abstract
<p>We evaluate analytical methods for characterizing hydrated and hydrous iron sulfate minerals (HHIS) that are typically metastable in air or vacuum, commonly form micrometer-sized particles, and contain multi-valent and light elements (Fe<sup>2+</sup>, Fe<sup>3+</sup>, OH-, and H<sub>2</sub>O) that may be challenging to quantify. We synthesized or obtained HHIS-szomolnokite, melanterite, rhomboclase, schwertmannite, ferricopiapite, paracoquimbite, and jarosite-as well as Fe-oxides. These nominally pure samples were characterized with X-ray diffraction (XRD), and then used to evaluate bulk analyses obtained from combined inductively coupled plasma, optical emission spectroscopy (ICP-OES), ion chromatography (IC), Mössbauer spectroscopy, and mass spectrometry. Integrated bulk analyses showed excellent agreement with the nominal formulas for the minerals. Because HHIS commonly form micro-sized particles-for example, HHIS found in acid mine drainage (AMD) environments and in martian meteorites-it is necessary to develop micro-analytical techniques. Microscopic mid-infrared spectroscopy allows the analyst to successfully discriminate among HHIS with minimal sample preparation on the small scale (̃40 × 40 μm). For chemical analysis, electron probe microanalysis (EPMA) is preferred for samples that can be mounted, polished, coated, and that are stable under high vacuum; however, few HHIS meet those criteria. To characterize HHIS compositions, we show that multiple low-vacuum scanning electron microscopy (SEM) analyses of the same uncoated, unpolished mineral are required. Analysis of each mineral shows linear trends on ternary diagrams of 5×Fe-SO<sub>4</sub>-O (where oxygen is in O, OH, and H<sub>2</sub>O) that may be used to narrow down the HHIS mineralogy. Low-vacuum SEM also provides invaluable information about the geochemical and textural context of the samples. Our study provides protocols for microanalysis of these challenging, fine-grained, and metastable HHIS that may also be applied to other mineral groups.</p>