Spectroscopy of natural silica-rich glasses.

Faulques, Eric; Fritsch, Emmanuel; Ostroumov, Mikhail

doi:10.2465/jmps.96.120

Cited by 24 publications

(29 citation statements)

References 12 publications

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“…However, a closer look at the spectrum in Fig. 2 allows us to distinguish some vibrational bands, also described elsewhere [11,14]. Two typical broad bands -one around 480 cm -1 and the other at 820 cm is the symmetric motion of adjacent Si atoms with respect to a bridging oxygen (Si-O-Si) [14].…”

Section: Resultsmentioning

confidence: 71%

“…Giuli et al [10] concluded, based on XANES analysis of the Fe oxidation state, that LDG is definitely an impactite, not a tektite. This idea was also supported by Faulques et al [14] who analysed IR and Raman spectra of several natural glasses, proving a strong similarity in structure between LDG, Darwin glass and vitreous silica. On the other hand, Stebbins et al are in favor of the hypothesis that LDG does not retain a high pressure structure, despite its origin due to a hypervelocity impact [15].…”

Section: The Mystery Of the Origin Of Libyan Desert Glassmentioning

confidence: 58%

“…2 allows us to distinguish some vibrational bands, also described elsewhere [11,14]. Two typical broad bands -one around 480 cm -1 and the other at 820 cm is the symmetric motion of adjacent Si atoms with respect to a bridging oxygen (Si-O-Si) [14]. According to Faulques et al [14], the overall shape of the Raman spectrum is very much alike for both LDG and Darwin glass which -with no doubts -is an impactite, however far younger than LDG (only 730,000 years old).…”

Section: Resultsmentioning

confidence: 99%

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Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

Swaenen¹,

Stefaniak

Frost

et al. 2010

Anal Bioanal Chem

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Several specimens of Libyan Desert Glass (LDG), an enigmatic natural glass fromEgypt, were subjected to investigation by micro-Raman spectroscopy. The spectra of inclusions inside the LDG samples were successfully measured through the layers of glass and the mineral species were identified on this basis. The presence of cristobalite as typical for high-temperature melt products was confirmed, together with co-existing quartz. TiO 2 was determined in two polymorphic species, rutile and anatase. MicroRaman spectroscopy proved also the presence of minerals unusual for high-temperature glasses such as anhydrite and aragonite.

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Section: Resultsmentioning

confidence: 71%

Section: The Mystery Of the Origin Of Libyan Desert Glassmentioning

confidence: 58%

Section: Resultsmentioning

confidence: 99%

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Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

Swaenen¹,

Stefaniak

Frost

et al. 2010

Anal Bioanal Chem

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“…4b) exhibit a broad feature between 100 and 550 cm -1 . It is worth noting that these components coincide well with four intense, superimposed Raman bands of opal that occur at 312, 410, 450 and 489 cm -1 (Faulques et al 2001). Raman spectra of this fraction hardly show the weal line at 967 and 1630 cm -1 characteristic of Si-OH bond and H-O-H bending of hydrogen bonded water (Ostrooumov et al 1999).…”

Section: Raman and Infrared Spectrometrymentioning

confidence: 68%

Mineralogical and geochemical studies of hardened subsurface layers in soils of the Azufres and Atecuaro volcanic calderas, southwestern Mexico

Ostrooumov¹,

Monroy²,

Servenay³

2005

Can. J. Soil. Sci.

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Ostrooumov, M., Monroy, V. H. G. and Servenay, A. 2005. Mineralogical and geochemical studies of hardened subsurface layers in soils of the Azufres and Atecuaro volcanic calderas, southwestern Mexico. Can. J. Soil Sci. 85: 611-624. Free silica and halloysite-bearing hardened subsurface layers in the ash fall deposits of the Azufres and Atecuaro volcanic calderas (Michoacan State, southwestern Mexico), known as "tepetates", have been characterized by chemical analysis, X-ray diffraction (XRD), Raman and Infrared spectrometry, optical (OM) and scanning (SEM) microscopy with energy dispersive X-ray analysis (EDXRA). Chemical analysis of these weathered and hardened formations shows the oxidation of Fe 2+ , enrichment of Al, Fe 3+ and Ti, loss of Si, Na, Ca, K, Mg, and formation of minerals with hydroxyls groups. Tepetates are characterized by elevated SiO 2 /Al 2 O 3 molar ratios (4. 86-8.82) that show part of the SiO 2 has crystallized in free siliceous phases. X-ray analysis reveals hydrated (1.0 nm) and dehydrated halloysite (0.7 nm), sanidine, plagioclases, cristobalite, and tridymite. Raman and infrared spectra confirm the presence of these mineral phases and show that the structural transformations occur in opal neoformations. SEM shows a compact matrix with a skeleton of different phenocrysts (aluminosilicates, ferromagnesian minerals and various crystalline silica phases) and the presence of non-crystalline silica (volcanic glass and opal with different degrees of crystallinity). The tepetates form by interaction of two processes: volcanic ash fall then subsequent weathering under variable climatic conditions. These indurated horizons are partly or totally cemented by the diagenetic secondary minerals: non-crystalline silica with variable crystal chemical characteristics and clay minerals. . Ils ont pour cela recouru à l'analyse chimique, à la diffraction par rayons X, à la spectrométrie Raman et à infrarouge, à la microscopie photonique et par balayage (MB) ainsi qu'à l'analyse radiologique par dispersion d'énergie. L'analyse chimique de ces formations durcies et altérées révèle l'oxydation du Fe 2+ , un apport d'Al, de Fe 3+ et de Ti, la perte de Si, Na, Ca, K et Mg, et la formation de minéraux à groupes hydroxyles. Les tepetates se caractérisent par un ratio molaire élevé de SiO 2 /Al 2 O 3 (4,86 à 8,82), signe qu'une partie du SiO 2 s'est cristallisée dans la silice libre. L'analyse radiologique révèle de l'halloysite hydratée (1,0 nm) et déshydratée (0,7 nm), de la sanidine, des plagioclases, de la cristobalite et de la tridymite. L'analyse par spectrométrie Raman et infrarouge confirme la présence de ces phases minérales et montre que les transformations structurales surviennent dans les néoformations d'opales. La MB montre une matrice compacte ayant pour squelette différents phénocristaux (aluminosilicates, minéraux ferro-magnésiens et diverses phases de silice cristalline) ainsi que la présence de silice non cristalline (verre volcanique et opales à cristallinité variable). Les tepetates naissent ...

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“…Raman spectroscopy is a non-destructive analytical technique that has been used to investigate a range of glassy geological materials including obsidian (White & Minser 1984;Bellot-Gurlet et al 2004;Shimoda et al 2004;Arias et al 2006;Di Muro et al 2006;Carter et al 2008), tektites (White & Minser 1984;Faulques et al 2001;Wondraczek et al 2003) and fulgurites (White & Minser 1984;Champagnon et al 1997). The Raman spectra of glassy silicate materials are characterized by a number of broad features that reflect the connectivity of the SiO 4 polymeric units within the threedimensional framework of the silicate structure.…”

Section: Introductionmentioning

confidence: 99%

A Raman spectroscopic study of a fulgurite

Carter

Hargreaves

Kee

et al. 2010

Phil. Trans. R. Soc. A.

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A Raman microspectroscopic study of several fulgurites has been undertaken. A fulgurite is an amorphous mineraloid, a superheated glassy solid that is formed when a lightning bolt hits a sandy or rocky ground and thermal energy is transferred. The Raman spectra revealed several forms of crystalline and fused silica and also the presence of polyaromatic hydrocarbons found in an interfacial zone of a glass bubble. This, together with the presence of anatase, a low-temperature polymorph of TiO 2 , suggested that some regions of the fulgurite specimen were not subjected to temperatures of 1800 • C, which are attained when lightning hits the surface of sand or a rock.

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Spectroscopy of natural silica-rich glasses.

Cited by 24 publications

References 12 publications

Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

Investigation of inclusions trapped inside Libyan desert glass by Raman microscopy

Mineralogical and geochemical studies of hardened subsurface layers in soils of the Azufres and Atecuaro volcanic calderas, southwestern Mexico

A Raman spectroscopic study of a fulgurite

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