Fluvial transport of impact evidence from cratonic interior to passive margin: Vredefort-derived shocked zircon on the Atlantic coast of South Africak

Scientists have documented the extraordinary fluvial transport of shocked zircon grains from the 2.02 billion-year-old Vredefort impact structure in South Africa to the Atlantic coast, spanning over 1940 kilometers through the Vaal-Orange river system. This discovery highlights the resilience and detectability of detrital shocked minerals, which retain diagnostic microstructures and geochemical fingerprints even after extensive transport. The study involved a comprehensive survey of 11,168 zircon grains from the Orange River basin and coastal sediments, identifying three shocked grains (0.03% abundance) with {112} twins and U-Pb ages consistent with the Vredefort source. This research bridges impact cratering and sedimentology, offering a novel method to trace eroded impact structures across geological time, from the Hadean to the Phanerozoic.

Montalvo, S. D., Cavosie, A. J., Erickson, T. M., & Talavera, C. (2017). Fluvial transport of impact evidence from cratonic interior to passive margin: Vredefort-derived shocked zircon on the Atlantic coast of South Africak. American Mineralogist, 102(4), 813–823. https://doi.org/10.2138/am-2017-5857ccbyncnd