Impact Geologists, Beware!
Commentary in Geophysical Research Letters
For decades now, impact crater geologists have relied on a seemingly infallible test for the pedigree of a suspected impact structure: If you can find shock-metamorphosed minerals, especially quartz, then the structure was made by a forceful extraterrestrial impact onto our surface because no other known process could achieve the pressures necessary to alter quartz into one of several high-pressure forms, commonly referred to as “shocked” quartz. This idea has continued to hold sway in the field in spite of a few cases where such quartz is found, but an impact origin seems unlikely [Haines et al., 2001; Schultz et al., 2004]. Now, a group at the University of Pennsylvania [Chen et al., 2017] has challenged this canon by demonstrating that, under the right circumstances, ordinary storm-generated lightning may produce shock lamellae in quartz. More…
By H. J. Melosh, Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, West Lafayette, IN
- Article Category
- Research Letters
- Solid Earth
Generation of shock lamellae and melting in rocks by lightning‐induced shock waves and electrical heating
- First Published:
- | DOI:
Eos.org: Earth & Space Science News
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