Sudbury Basin
Coordinates: 46 ° 36 ' N , 81 ° 11' W
The Sudbury Basin ( English Sudbury Basin ; also known as "Sudbury Crater") is - after the Vredefort Crater in South Africa - the second largest known impact crater on earth. The basin is located near the city of Greater Sudbury in the Canadian province of Ontario and was formed when an approximately 10 km large asteroid impacted around 1.8 billion years ago. The crater originally had a diameter of approx. 200 to 250 km. The crater was deformed by geological processes and brought into its current, smaller and elliptical shape of 60 km × 30 km.
To the northeast, the basin borders the crater that Wanapitei Lake fills. This impact crater is 8 km in diameter and, at 37 million years old, is much younger than Sudbury crater.
Effects
The Sudbury Basin is home to the richest nickel deposits currently known on earth. They arose orthomagmatic during the impact. By relieving pressure shortly after the asteroid hit, a process of melting the ultramafic rock took place, which led to the formation of a gabbroid melt. The nickel ore ( pentlandite ) was then created through the separation of sulphidic and silicate melt and the subsequent segregation of the sulphidic melt at the bottom of the ultramafic intrusion . The ore is located on the rim and bottom of the former crater. The impact may also have promoted the mixing of the ocean at that time and thus ended the formation of the banded iron ores .
See also
Individual evidence
- ↑ John F. Slack, Cannon, William F .: Extraterrestrial demise of banded iron formations 1.85 billion years ago . In: Geology . 37, No. 11, 2009, pp. 1011-1014. doi : 10.1130 / G30259A.1 .
Web links
- "Sudbury Meteorite Crater" (English)
- Sudbury in the Earth Impact Database (English)