Sudbury Basin, Ontario, Canada (confirmed 1960s)
Canada's Sudbury Basin, a 130-kilometer-long elliptical structure, was mined for nickel and copper for decades before geologists recognized it as the scar of a 1.85-billion-year-old asteroid impact. Its economic metals, now understood to have been concentrated by the impact's heat and shock, made it one of the world's most valuable mining districts.
Recognition of Sudbury's impact origin reshaped understanding of how impact events can concentrate economic mineral deposits.
Sudbury became a global reference site for impact geology and a training ground for Apollo astronauts in the 1970s, establishing the template later used at Kamestastin and now considered for Uhackatik.
Sudbury shows that a massive crater can sit in plain sight, economically exploited for decades before its extraterrestrial origin is recognized. It also demonstrates the pattern Osinski now follows: using well-preserved craters as astronaut training grounds.
