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

The record of terrestrial impact events is incomplete with no Archean structures discovered, despite the expected abundance collisions that must have occurred. Because been identified, necessary conditions to preserve an structure longer than 2 Byr are unknown. One significant effect shock metamorphism physical properties target rocks change, resulting in distinctive geophysical signatures structures. To evaluate preservation potential structures, we deeply eroded Proterozoic Vredefort examine changes and remnant signature compare results well-preserved Chicxulub structure. major structural features similar profile at a depth 8–10 km. rocks, while shocked, do not measurable their properties. gravity minor controlled by collapsed transient crater rim uplifted Moho surface. We anticipate erosion additional 1 km would remove evidence impact, regardless initial size, >10 result removal most for any from geological record. This study demonstrates identification geologically old (i.e., Archean) limited lack associated craters.