Multi-stage ultrahigh temperature metamorphism in the lower crust of the Kaapvaal craton recorded by U–Pb ages of garnet

New U–Pb garnet ages from the Vredefort Dome reveal prolonged ultrahigh-temperature (UHT) metamorphism spanning 400 million years in the lower crust of the Kaapvaal craton. Three distinct age peaks at 3.09, 3.01, and 2.75 Ga correspond to key geological events: an ancient collision (3.2 Ga), magmatic rejuvenation during Dominion Group volcanism (3.0–2.95 Ga), and Ventersdorp flood basalt activity (~2.72 Ga). The study highlights garnet's ability to retain high-temperature signatures (>1100 °C) over billions of years, providing a unique record of crustal processes. Researchers used split-stream LA-SF/MC-ICPMS on garnets from UHT granulites to uncover this multi-stage metamorphic history.

Shu, Q., Beranoaguirre, A., Albert, R., Millonig, L. J., Walters, J. B., Marschall, H. R., Gerdes, A., Hoefer, H. E., Hezel, D., & Brey, G. P. (2024). Multi-stage ultrahigh temperature metamorphism in the lower crust of the Kaapvaal craton recorded by U–Pb ages of garnet. Contributions to Mineralogy and Petrology, 179(5). https://doi.org/10.1007/s00410-024-02121-4