Sudbury Basin

The Sudbury Basin is the second largest impact crater on earth. The crater, formed about 1.85 billion years ago, originally had a diameter of 250 km round crater. Subsequent geological processes have deformed the crater into the current smaller, oval (60 x 30 km) shape.

Lake Wanapitei, at the northeastern edge of the Sudbury Basin, fills another impact crater with a diameter of 8 km, and a age of 37 million yeras.