List of impact craters in North America

Columns: Name | Location | Diameter ( km ) | Age ( Ma/millions )
Ames | Oklahoma | 16 | 470 ± 30 | Avak | Alaska | 12 | < 95 | Barringer | Arizona | 1.19 | 0.049 ± 0.003 | Beaverhead | Idaho , Montana | 60 | 600 | Calvin | Michigan | 8.5 | 450 ± 10 | Chesapeake Bay | Virginia | 90 | 35.5 ± 0.3 | Cloud Creek | Wyoming | 7 | 190 ± 30

Example questions:
Approximately how many years ago was the impact crater created in Tennessee ? | When was the impact crater discovered in Oklahoma ? | What kind of rocks cover the structure of the impact crater that 's in Alaska ? | When was the impact crater found in Indiana discovered ?

Answers:
360 million years ago | 1991 | Permanently frozen Pliocene and Pleistocene rock | 1880