A geochemical contribution to the discussion about the genesis of impact-related pseudotachylitic breccias: Studies of PTB in the Otavi and Kudu Quarries of the Vredefort Dome support the“In Situ Formation”hypothesis

Geochemical analysis of pseudotachylitic breccias (PTB) from the Otavi and Kudu quarries at the Vredefort Dome, South Africa, supports the 'In Situ Formation' hypothesis. This study demonstrates that PTB formed from local country rocks without significant contribution from impact melt or fault-related friction melting. The research employed petrographic examination and chemical systematics to show that PTB chemistry aligns with adjacent granitic gneiss, amphibolite, and granitoids, ruling out external components like Vredefort Granophyre. Harmonic least-squares mixing calculations further excluded additional material sources, reinforcing the conclusion that rapid decompression during central uplift formation led to local melting and melt pooling in dilation sites.

Reimold, W. U., Hoffmann, M., Hauser, N., Schmitt, R.-T., Zaag, P. T., & Mohr-Westerheide, T. (2016). A geochemical contribution to the discussion about the genesis of impact-related pseudotachylitic breccias: Studies of PTB in the Otavi and Kudu Quarries of the Vredefort Dome support the“In Situ Formation”hypothesis. South African Journal of Geology, 119(3), 453–472. https://doi.org/10.2113/gssajg.119.3.453