Condensate glasses from the Zhamanshin crater. I. Irghizites

Горностаева, Т. А.; Мохов, А. В.; Карташов, П. М.; Богатиков, О. А.

doi:10.1134/s0869591115060028

Cited by 18 publications

(4 citation statements)

References 30 publications

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“…Additionally, the tektites differ from the UHPHT Kara glasses by significantly lower ratios of Al/(Si + Al) and Na/(Na + K). It is important to note that the compositions similar to those of ZH1 and ZH2 samples for irgizites of the Zhamanshin meteorite crater were obtained earlier by other authors [19][20][21][22].…”

Section: Samples Characterizationsupporting

confidence: 76%

“…The width of the chemical shift distribution ∆ CS for the zhemanshinite samples is much higher than that for the Kara glasses, which indicates more clustering of Al and Fe atoms in the LP tektite glass framework. This conclusion does not contradict the results of the study of the zhemanshinites by high-resolution microscopy [21].…”

Section: Discussionsupporting

confidence: 61%

“…Tektites are hardened drops of impact melt ejected into the atmosphere during the formation of a crater, i.e., condensed at atmospheric pressure. They are related to LP glasses [19][20][21]. A number of petrographic and chemical features indicate that tektites resulted from high-temperature melting (more than 2000 K) with fast melt cooling.…”

Section: Methodsmentioning

confidence: 99%

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NMR Spectral Characteristics of Ultrahigh Pressure High Temperature Impact Glasses of the Giant Kara Crater (Pay-Khoy, Russia)

et al. 2021

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In this study, we carried out the analysis of the impact melt vein glasses from the Kara impact crater (Russia) in comparison to low-pressure impact melt glasses (tektites) of the Zhamanshin crater (Kazakhstan). 27Al, 23Na, and 29Si MAS NMR spectra of the samples of these glasses were analyzed. The samples of the natural glass contained inclusions of crystalline phases, paramagnetic elements that greatly complicate and distort the NMR signals from the glass phase itself. Taking into account the Mossbauer distribution of Fe in these glasses, the analysis of the spectra of MAS NMR of glass network-former (Si, Al) and potential network-modifiers (Na) of nuclei leads to the conclusion that the Kara impact melt vein glasses are characterized by complete polymerization of (Si,Al)O4 tetrahedral structural units. The NMR features of the glasses are consistent with the vein hypothesis of their formation under conditions of high pressures and temperatures resulting in their fluidity, relatively slow solidification with partial melt differentiation, polymerization, and precipitation of mineral phases as the impact melt cools. The 70 Ma stability of the Kara impact vein glass can be explained by the stabilization of the glass network with primary fine-dispersed pyroxene and coesite precipitates and by the high polymerization level of the impact glass.

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Section: Samples Characterizationsupporting

confidence: 76%

Section: Discussionsupporting

confidence: 61%

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NMR Spectral Characteristics of Ultrahigh Pressure High Temperature Impact Glasses of the Giant Kara Crater (Pay-Khoy, Russia)

et al. 2021

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“…The microstructures of natural high-pressure glasses have only been slightly discussed 11,[22][23][24] , and the comprehensive study of the structure and properties of natural high-pressure glasses remains practically unexplored.…”

mentioning

confidence: 99%

Mysterious long-living ultrahigh-pressure or secondary impact crisis

Шумилова

Zubov

Исаенко

et al. 2020

Sci Rep

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High-pressure glass has attracted interest in terms of both its fundamental state under extreme conditions and its possible applications as an advanced material. in this context, natural impact glasses are of considerable interest because they are formed under ultrahigh-pressure and high-temperature (UHpHt) conditions in larger volumes than laboratory fabrication can produce. Studying the UHpHt glasses of the unique giant Kara astrobleme (Russia), we found that the specific geological position of the UHpHt melt glass veins points to an origin from a secondary ultrahigh-pressure (UHp) melt according to the characteristics of the host suevites, which suggest later bottom flow. Here, we propose a fundamentally novel model involving an upward-injected UHp melt complex with complicated multilevel and multi-process differentiation based on observations of the UHP silica glass, single-crystal coesite and related UHp smectite that crystallized from an impact-generated hydrous melt. this model proposes a secondary UHP crisis during the modification stage of the Kara crater formation. The results are very important for addressing fundamental problems in fields as diverse as condensed matter states under extreme pressure and temperature (pt) conditions, material and geological reconstructions of impact structures, water conditions in mineral substances under UHp conditions in the deep earth, and the duration and magnitude of the catastrophic effects of large asteroid impacts. The structure and properties of disordered substances have been studied for a long time and used in a wide range of applications. The behaviour of such substances under extreme conditions, including intense compression, is particularly interesting and is actively studied both theoretically and experimentally 1-7. High-pressure glasses have drawn interest both fundamentally as a material formed under extreme conditions and as a novel compound that could be used in new applications 8,9. The behaviour of disordered and weakly ordered systems under compression has been studied in microvolumes via diamond anvil. Typically, the compression process is performed at pressures of up to 100 GPa and sometimes higher. Furthermore, the experiments are typically performed at room temperature 1,4-6,9. Only a few experiments combining both high pressures and high temperatures have been carried out. However, such studies are intriguing because the simultaneous effects of temperature and pressure can produce profound internal changes in a substance. For example, SiO 2 glass has a significantly higher density and strength at a pressure of approximately 8 GPa and a temperature of 1100 °C than under cold compression 10. The most important properties expected from these glasses are the heat capacity, hardness, unusual optical properties and other physical properties, which can be used in high-tech materials and technologies, including high-energy lasers, microelectronics and innovative optics. Glasses with microstructural features at a nanoscale are potential basic matrices ...

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