Zircon Microstructures Record Deformation History of Shock- and Tectonically-generated Pseudotachylites: a Case Study from the Vredefort Impact Structure, South Africa

High-strain rate deformation can cause in situ melting of rocks, resulting in the formation of dark, micro- to nanocrystalline pseudotachylite veins. On Earth, pseudotachylite veins form during meteorite impacts, large landslides, and earthquakes. Within the Vredefort impact structure, both impact-generated and (pre-impact) tectonically-generated pseudotachylite veins have been described, but are challenging to distinguish. Here, we demonstrate...