Impact Events

A shocking discovery

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Science  29 Sep 2017:
Vol. 357, Issue 6358, pp. 1367-1368
DOI: 10.1126/science.357.6358.1367-c

Lightning strikes can produce shocked quartz.

PHOTO: MARTIN SHIELDS/SCIENCE SOURCE

Shocked quartz—whose crystalline structure is deformed along planes inside the crystal, a result of sudden high pressure and heating—long has been considered to be an unequivocal signature of the impact of an extraterrestrial object such as a meteorite. This favorite tool of geologists searching for proof of an impact may not be so foolproof after all, though. Chen et al. simulated the pressure and temperature caused by an idealized lightning strike on rocks and found that lightning can produce the same conditions and effects caused by impact events. Therefore, the presence of shock features in quartz should not be taken as unequivocal evidence for an extraterrestrial impact.

Geophys. Res. Lett. 10.1002/2017GL073843 (2017).

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