Fracture Analysis of α-Quartz Crystals Subjected to Shear Stress

Martinelli, Giovanni; Plescia, P.; Tempesta, Emanuela; Paris, Enrico; Gallucci, Francesco

doi:10.3390/min10100870

Cited by 6 publications

(1 citation statement)

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“…Wilk et al [6] found amorphous silica in experimentally shocked rocks called shatter cones that formed at low shock pressures of 0.5-5 GPa. Laboratory shock experiments by Martinelli et al [79] used quartz crystals with a minimum diameter of 3400 µm, larger than we tested. The reported compression applied was as low as 0.2 GPa; the maximum compression applied is unclear but appears to have been <1 GPa.…”

Section: Previous Studies Of Amorphous Silica In Quartz Grainsmentioning

confidence: 99%

Microstructures in Shocked Quartz: Linking Nuclear Airbursts and Meteorite Impacts

Hermes¹,

Wenk²,

Kennett³

et al. 2023

Preprint

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Many studies of hypervelocity impact craters have described the characteristics of quartz grains shock-metamorphosed at high pressures of > 10 GPa. In contrast, few studies have investigated shock metamorphism at lower shock pressures. In this study, we test the hypothesis that low-pressure shock metamorphism occurs in near-surface nuclear airbursts and that this process shares essential characteristics with crater-forming impact events. To investigate low-grade shock microstructures, we compared quartz grains from Meteor Crater, a 1.2-km-wide impact crater, to those from near-surface nuclear airbursts at the Alamogordo Bombing Range, New Mexico in 1945 and Kazakhstan in 1949/1953. This investigation utilized a comprehensive analytical suite of high-resolution techniques, including transmission electron microscopy (TEM) and electron backscatter diffraction (EBSD). Meteor Crater and the nuclear test sites all exhibit quartz grains with closely-spaced, sub-micron-wide fractures that appear to have formed at low shock pressures. Significantly, these micro-fractures are closely associated with Dauphiné twins and are filled with amorphous silica (glass), widely considered a classic indicator of shock metamorphism. Thus, this study confirms that glass-filled shock fractures in quartz form during near-surface nuclear airbursts, as well as crater-forming impact events, and by extension, it suggests that they may form in any near-surface cosmic airbursts in which the shockwave is coupled to Earth’s surface. The robust characterization of such events is crucial because of their potential catastrophic effects on the Earth’s environmental and biotic systems.

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Section: Previous Studies Of Amorphous Silica In Quartz Grainsmentioning

confidence: 99%