Electron irradiation damage in natural quartz grains

Carter, C. B.; Kohlstedt, D. L.

doi:10.1007/bf00308226

Cited by 27 publications

(11 citation statements)

References 12 publications

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“…Similar to observations in a-quartz and in zeolites, disordered areas such as dislocations seemed to be a source of enhanced vitrificatioñ Bursill et al, 1980Bursill et al, , 1981Hobbs & Pascucci, 1980;Carter & Kohlstedt, 1981;Pascucci et al, 1983;Acosta et al, 1993!. However, unlike a-quartz, in which the crystallineamorphous boundary progresses at a constant rate from the dislocation core~Carter & Kohlstedt, 1981!, the loss of long-range order around dislocations in MCM-41 seems to progress quickly at first, then slows or stops. Similar to observations in a-quartz and in zeolites, disordered areas such as dislocations seemed to be a source of enhanced vitrificatioñ Bursill et al, 1980Bursill et al, , 1981Hobbs & Pascucci, 1980;Carter & Kohlstedt, 1981;Pascucci et al, 1983;Acosta et al, 1993!. However, unlike a-quartz, in which the crystallineamorphous boundary progresses at a constant rate from the dislocation core~Carter & Kohlstedt, 1981!, the loss of long-range order around dislocations in MCM-41 seems to progress quickly at first, then slows or stops.…”

Section: Effect Of Structural Defectssupporting

confidence: 60%

Electron Radiation Damage of MCM-41 and Related Materials

Blanford

Carter

2003

Microsc Microanal

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The article compares the relative stability of MCM-41 and related mesoporous materials in electron beam at an accelerating voltage of 100-300 kV. The work encountered in electron microscopy presents a comparison with similar research that has been carried out on nonporous and microporous silicates, especially a-quartz and zeolite Y. The trends in stability are analyzed, classifying the effects of sample preparation, organic and inorganic moieties, and electron accelerating voltage on beam stability. A higher synthesis temperature, the use of an acid catalyst in the synthesis, and the presence of additional organic or inorganic material within the channels were all found to stabilize these materials. The dose required to completely disrupt the structure increased with accelerating voltage for nearly all samples, suggesting a primarily radiolytic damage mechanism.The exception, MCM-41 containing nanometer-sized titania particles in its channels, was found to be almost insensitive to accelerating voltage.

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Section: Effect Of Structural Defectssupporting

confidence: 60%

Electron Radiation Damage of MCM-41 and Related Materials

Blanford

Carter

2003

Microsc Microanal

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“…This defect can form as a result of beam damage in quartz, by dissociation of strained Si-O bonds (Devine 1990;Stevens Kalceff and Phillips 1995). In TEM, localised electron beam damage at dislocations, Brazil twin boundaries and, to a lesser extent, Dauphiné twin boundaries are a commonly observed phenomenon and continued beam damage finally results in complete (local) amorphisation (Carter and Kohlstedt 1981;Cherns et al 1980;McLaren et al 1970;Comer 1972;McLaren and Phakey 1965). Similar damage caused by inelastic scattering of the incoming electrons also occurs in the SEM (Vigouroux et al 1985, Stevens Kalceff 2009 andreferences therein).…”

Section: Discussionmentioning

confidence: 85%

Scanning electron microscope cathodoluminescence imaging of subgrain boundaries, twins and planar deformation features in quartz

2016

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“…Sanchez-Navas et al, 1998). Therefore, we interpret these electron-lucent structures are likely caused by electron beam damage, also in analogy to electron beam damaged quartz that occurs as strain contrast centres (Carter & Kohlstedt, 1981;Martin et al, 1996).…”

Section: Nanoscale Structure Of a Microbial Mat In Badagaon Stromatolmentioning

confidence: 92%

Nanoscale petrographic and geochemical insights on the origin of the Palaeoproterozoic stromatolitic phosphorites from Aravalli Supergroup, India

et al. 2015

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Stromatolites composed of apatite occur in post-Lomagundi-Jatuli successions (late Palaeoproterozoic) and suggest the emergence of novel types of biomineralization at that time. The microscopic and nanoscopic petrology of organic matter in stromatolitic phosphorites might provide insights into the suite of diagenetic processes that formed these types of stromatolites. Correlated geochemical micro-analyses of the organic matter could also yield molecular, elemental and isotopic compositions and thus insights into the role of specific micro-organisms among these communities. Here, we report on the occurrence of nanoscopic disseminated organic matter in the Palaeoproterozoic stromatolitic phosphorite from the Aravalli Supergroup of north-west India. Organic petrography by micro-Raman and Transmission Electron Microscopy demonstrates syngeneity of the organic matter. Total organic carbon contents of these stromatolitic phosphorite columns are between 0.05 and 3.0 wt% and have a large range of δ(13) Corg values with an average of -18.5‰ (1σ = 4.5‰). δ(15) N values of decarbonated rock powders are between -1.2 and +2.7‰. These isotopic compositions point to the important role of biological N2 -fixation and CO2 -fixation by the pentose phosphate pathway consistent with a population of cyanobacteria. Microscopic spheroidal grains of apatite (MSGA) occur in association with calcite microspar in microbial mats from stromatolite columns and with chert in the core of diagenetic apatite rosettes. Organic matter extracted from the stromatolitic phosphorites contains a range of molecular functional group (e.g. carboxylic acid, alcohol, and aliphatic hydrocarbons) as well as nitrile and nitro groups as determined from C- and N-XANES spectra. The presence of organic nitrogen was independently confirmed by a CN(-) peak detected by ToF-SIMS. Nanoscale petrography and geochemistry allow for a refinement of the formation model for the accretion and phototrophic growth of stromatolites. The original microbial biomass is inferred to have been dominated by cyanobacteria, which might be an important contributor of organic matter in shallow-marine phosphorites.

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Electron irradiation damage in natural quartz grains

Cited by 27 publications

References 12 publications

Electron Radiation Damage of MCM-41 and Related Materials

Electron Radiation Damage of MCM-41 and Related Materials

Scanning electron microscope cathodoluminescence imaging of subgrain boundaries, twins and planar deformation features in quartz

Nanoscale petrographic and geochemical insights on the origin of the Palaeoproterozoic stromatolitic phosphorites from Aravalli Supergroup, India

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