The Chesapeake Bay impact
A second large asteroid arrives within 25,000 years of the first, and its crater still shapes Virginia.
- When
- Known to
- ± 300 thousand years
- Era
- Eocene, Cenozoic
An impactor strikes the shallow shelf off eastern North America around 35.5 million years ago, cutting an 85-kilometre crater now buried under sediment beneath the lower Chesapeake Bay. The structure was only recognised in the 1990s, from drill cores and seismic surveys; it explains the bay's location, disrupts local aquifers and leaves a body of ancient salty groundwater trapped in the crater fill. Together with Popigai it forms a late Eocene impact cluster — and, notably, recent work finds no climate anomaly or extinction associated with either.