Long-term isostatic relaxation of large terrestrial impact structures: structural characteristics inferred from scaled analogue experiments

Analogue experiments reveal that long-term isostatic relaxation drives the formation of crater floor fractures through upward flexing, with lower crustal flow toward crater centers. This process, dependent on crater diameter and crustal strength, explains prominent structural vestiges like impact melt rock dikes observed in large terrestrial craters such as Sudbury and Vredefort. The study quantifies deformation zones in the upper crust, establishing a relationship between crater dimensions and fracture geometry. It also demonstrates that crater floor uplift is compensated by peripheral subsidence, potentially operating over hundreds of thousands of years. These findings provide insights into the structural evolution of impact craters on rocky celestial bodies.

Eisermann, J. O., & Riller, U. (2024). Long-term isostatic relaxation of large terrestrial impact structures: structural characteristics inferred from scaled analogue experiments. Earth and Planetary Science Letters, 647, 119029. https://doi.org/10.1016/j.epsl.2024.119029