Publications
Correlating planar microstructures in shocked zircon from the Vredefort Dome at multiple scales: Crystallographic modeling, external and internal imaging, and EBSD structural analysis
Researchers have identified seven distinct planar fracture orientations in shocked zircon from the Vredefort Dome, providing new insights into the microstructural changes induced by high-pressure impacts. These fractures—(010), (100), (112), (1̄12), (1̄1̄2), and (011)—were documented across multiple scales using crystallographic modeling, 360° prism backscattered electron imaging, and sub-micrometer-scale EBSD analysis. Notably, some {112} fractures contain impact microtwins, the first reported in zircon, suggesting complex deformation mechanisms under extreme conditions (20–40 GPa). The study also clarifies the chronology of fracture formation, from early c-axis parallel fractures to later compressional (011) features and non-discrete crystal plastic deformation. By correlating grain-scale and sub-micrometer observations, this work refines our understanding of shock-induced microstructures in zircon, challenging prior nomenclature and advancing impact geology.
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.
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