Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry

Post-impact faulting has been identified in the Holfontein Granophyre Dike (HGD) of the Vredefort Impact Structure, South Africa, suggesting long-term crustal processes shaped the Earth's largest preserved impact crater. The study, combining remote sensing, geophysics, and geochemistry, revealed that the dike was segmented by an ENE–WSW trending sinistral strike-slip fault zone after solidification, despite no major post-impact tectonic events in the region. Geophysical modeling confirmed the shallow depth of the melt rock (<5 m), while petrographical and geochemical analyses showed indistinguishable compositions between dike segments. This segmentation is consistent with progressive uplift of the crater floor, mirroring long-term crustal adjustments observed in lunar craters.

Clark, M. D., Kovaleva, E., Huber, M. S., Fourie, F., & Harris, C. (2021). Post-Impact Faulting of the Holfontein Granophyre Dike of the Vredefort Impact Structure, South Africa, Inferred from Remote Sensing, Geophysics, and Geochemistry. Geosciences, 11(2), 96. https://doi.org/10.3390/geosciences11020096