Genesis of the mafic impact melt rock in the northwest sector of the Vredefort Dome, South Africa

New research reveals that the mafic phase of the Vredefort Granophyre, an impact melt rock from South Africa's Vredefort Domelikely formed through the admixture of a felsic impact melt with a mafic country rock, specifically epidiorite. This finding challenges previous hypotheses about its genesis and supports a model where contamination occurred during downward intrusion into the crater floor. The study employed geochemical and isotopic analyses (Sr-Nd) on samples from previously unstudied locations, confirming that a 20% admixture of epidiorite to felsic Granophyre best explains the observed chemical composition. This work advances understanding of impact melt dynamics and crustal interactions in large meteorite craters.

Reimold, W. U., Hauser, N., Oliveira, A. L., Maciel, A. R. P., Goderis, S., Pittarello, L., Wegner, W., Fischer‐Goedde, M., Koeberl, C., Debaille, V., & Silva Maia de Souza, C. (2023). Genesis of the mafic impact melt rock in the northwest sector of the Vredefort Dome, South Africa. Meteoritics & Planetary Science, 58(7), 907–944. Portico. https://doi.org/10.1111/maps.14027