Can Archean Impact Structures Be Discovered? A Case Study From Earth's Largest, Most Deeply Eroded Impact Structure

Deeply eroded impact structures, such as Earth's largest and most ancient Vredefort Dome, lose their geophysical signatures after significant erosion, making the discovery of Archean impact structures nearly impossible. Unlike well-preserved craters like Chicxulub, Vredefort's shocked target rocks show no measurable changes in physical properties, and its gravity signature is minimal, controlled only by remnants of the transient crater rim and uplifted Moho surface. This study suggests that erosion exceeding 1 km would eliminate evidence of impact, while >10 km of erosion would erase most traces from the geological record. The findings highlight the extreme preservation challenges for ancient impact structures, emphasizing that their identification is limited by the lack of detectable geophysical signatures in highly eroded craters.

Huber, M. S., Kovaleva, E., Rae, A. S. P., Tisato, N., & Gulick, S. P. S. (2023). Can Archean Impact Structures Be Discovered? A Case Study From Earth’s Largest, Most Deeply Eroded Impact Structure. Journal of Geophysical Research: Planets, 128(8). Portico. https://doi.org/10.1029/2022je007721