A record of ancient cataclysm in modern sand: Shock microstructures in detrital minerals from the Vaal River, Vredefort Dome, South Africa

Modern sediments from the Vaal River, South Africa, preserve shocked minerals up to 2 billion years after the impact event at the Vredefort Dome, revealing a new geological repository for ancient impact evidence. Detrital quartz, zircon, and monazite exhibit distinct shock microstructures, including planar fractures and Brazil twins, some of which may represent newly identified features. These findings demonstrate that shocked minerals can survive erosion and sedimentary transport, providing a means to identify distal ejecta from eroded impact structures. This discovery is particularly significant for studying early Earth impacts, where direct evidence is often obscured or buried.

Cavosie, A. J., Quintero, R. R., Radovan, H. A., & Moser, D. E. (2010). A record of ancient cataclysm in modern sand: Shock microstructures in detrital minerals from the Vaal River, Vredefort Dome, South Africa. Geological Society of America Bulletin, 122(11-12), 1968–1980. https://doi.org/10.1130/b30187.1