Aqueous alteration in CR chondrites: Meteorite parent body processes as analogue for long-term corrosion processes relevant for nuclear waste disposal

Morlok, A.; Libourel, G.

doi:10.1016/j.gca.2012.10.030

Cited by 24 publications

(23 citation statements)

References 47 publications

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“…Together the A and G bands indicate the presence of hydrous silicates, possibly clay minerals, in this meteorite sample. This is consistent with the identification of clay in CR2 chondrites (e.g., Morlok and Libourel 2013). On the other hand, the signature band of structural OH near 3650 cm À1 , as would be observed in some phyllosilicates, and which we have observed for grains of Orgueil and Tagish Lake by the same technique (Yesiltas, unpublished data), is absent in this spectrum.…”

Section: Caption and Insupporting

confidence: 92%

Organic and inorganic correlations for Northwest Africa 852 by synchrotron‐based Fourier transform infrared microspectroscopy

Yeşiltaş

Peale

Unger

et al. 2015

Meteorit & Planetary Scien

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Relationships between organic molecules and inorganic minerals are investigated in a single 34 lm diameter grain of the CR2 chondrite Northwest Africa 852 (NWA) 852 with submicron spatial resolution using synchrotron-based imaging micro-FTIR spectroscopy. Correlations based on absorption strength for the various constituents are determined using statistical correlation analysis. The silicate band is found to be correlated with the hydration band, and the latter is highly correlated with stretching modes of aliphatic hydrocarbons. Spatial distribution maps show that water+organic combination, silicate, OH, and C-H distributions overlap, suggesting a possible catalytic role of phyllosilicates in the formation of organics. In contrast, the carbonate band is anticorrelated with water+organic combination, however uncorrelated with any other spectral feature. The average ratio of asymmetric CH 2 and CH 3 band strengths (CH 2 /CH 3 = 2.53) for NWA 852 is similar to the average ratio of interplanetary dust particles (~2.40) and Wild 2 cometary dust particles (2.50), but it significantly exceeds that of interstellar medium objects (~1.00) and several aqueously altered carbonaceous chondrites (~1.40). This suggests organics of similar length/ branching, and perhaps similar formation regions, for NWA 852, Wild 2 dust particles, and interplanetary dust particles. The heterogeneous spatial distribution of ratio values indicates the presence of a mixture of aliphatic organic material with different length/branching, and thus a wide range of parent body processes, which occurred before the considered grain was formed.

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Section: Caption and Insupporting

confidence: 92%

Organic and inorganic correlations for Northwest Africa 852 by synchrotron‐based Fourier transform infrared microspectroscopy

Yeşiltaş

Peale

Unger

et al. 2015

Meteorit & Planetary Scien

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“…Both natural (basaltic glass, obsidian, meteorites) and archeological artifacts (Roman glass, stained glass window, slags from iron making, etc.) have given insight into how silicate glasses behave in various natural environments . However, none of the studied cases is similar to any expected nuclear system: glass compositions are different and the environmental conditions often are very dissimilar from those expected in a geological disposal of HLW or ILW glass.…”

Section: Evaluation and Testingmentioning

confidence: 99%

“…That is why a full understanding of the mechanisms controlling the dissolution of analog materials and the development of models to compare the different systems is required . In general, this mechanistic understanding is the key to comparing different glasses, disposal conditions, and near‐field environments …”

Section: Evaluation and Testingmentioning

confidence: 99%

Current Understanding and Remaining Challenges in Modeling Long‐Term Degradation of Borosilicate Nuclear Waste Glasses

Vienna

Ryan

Gin

et al. 2013

Int J of Appl Glass Sci

224

195

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Chemical durability is not a single material property that can be uniquely measured. Instead, it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment and modeling. High‐level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long‐term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near‐field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time scales. This article summarizes the current state of understanding of surface reactions, transport properties and ion exchange along with the near‐field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps.

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“…; Kallemeyn et al. ; Morlok and Libourel ). The CR group comprises some of the most pristine carbonaceous chondrites (Abreu and Brearley ).…”

Section: Introductionmentioning

confidence: 98%

Opaque assemblages in CR2 Graves Nunataks (GRA) 06100 as indicators of shock‐driven hydrothermal alteration in the CR chondrite parent body

Abreu

Bullock

2013

Meteorit & Planetary Scien

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Abstract-We have studied the petrologic characteristics of sulfide-metal lodes, polymineralic Fe-Ni nodules, and opaque assemblages in the CR2 chondrite Graves Nunataks (GRA) 06100, one of the most altered CR chondrites. Unlike low petrologic type CR chondrites, alteration of metal appears to have played a central role in the formation of secondary minerals in GRA 06100. Differences in the mineralogy and chemical compositions of materials in GRA 06100 suggest that it experienced higher temperatures than other CR2 chondrites. Mineralogic features indicative of high temperature include: (1) exsolution of Nipoor and Ni-rich metal from nebular kamacite; (2) formation of sulfides, oxides, and phosphates; (3) changes in the Co/Ni ratios; and (4) carbidization of Fe-Ni metal. The conspicuous absence of pentlandite may indicate that peak temperatures exceeded 600°C. Opaques appear to have been affected by the action of aqueous fluids that resulted in the formation of abundant oxides, Fe-rich carbonates, including endmember ankerite, and the sulfide-silicate-phosphate scorzalite. We suggest that these materials formed via impactdriven metamorphism. Mineralogic features indicative of impact metamorphism include (1) the presence of sulfide-metal lodes; (2) the abundance of polymineralic opaque assemblages with mosaic-like textures; and (3) the presence of suessite. Initial shock metamorphism probably resulted in replacement of nebular Fe-Ni metal in chondrules and in matrix by Nirich, Co-rich Fe metal, Al-Ti-Cr-rich alloys, and Fe sulfides, while subsequent hydrothermal alteration produced accessory oxides, phosphates, and Fe carbonates. An extensive network of sulfide-metal veins permitted effective exchange of siderophile elements from pre-existing metal nodules with adjacent chondrules and matrix, resulting in unusually high Fe contents in these objects.

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Aqueous alteration in CR chondrites: Meteorite parent body processes as analogue for long-term corrosion processes relevant for nuclear waste disposal

Cited by 24 publications

References 47 publications

Organic and inorganic correlations for Northwest Africa 852 by synchrotron‐based Fourier transform infrared microspectroscopy

Organic and inorganic correlations for Northwest Africa 852 by synchrotron‐based Fourier transform infrared microspectroscopy

Current Understanding and Remaining Challenges in Modeling Long‐Term Degradation of Borosilicate Nuclear Waste Glasses

Opaque assemblages in CR2 Graves Nunataks (GRA) 06100 as indicators of shock‐driven hydrothermal alteration in the CR chondrite parent body

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