Sudbury Basin

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Sudbury Basin is the oval structure, next to the much younger lake-filled Wanapitei crater

The Sudbury Basin, also known as Sudbury Structure, is the second largest known impact crater or astrobleme on Earth, and a major geologic structure in Ontario, Canada.

The basin is located on the Canadian Shield in the city of Greater Sudbury, Ontario. The former municipalities of Rayside-Balfour and Valley East lie within the Sudbury Basin, which is referred to locally as "The Valley". The urban core of the former city of Sudbury lies on the southern outskirts of the Basin.

[edit] Formation and structure

The Sudbury Basin is 60 km long, 30 km wide and 15 km deep. It was created as the result of a 10 km cometary impact that occurred 1.85 billion years ago in the Paleoproterozoic era. Its present size is believed to be a smaller portion of a 250 km round crater that the bolide originally created. Subsequent geological processes have deformed the crater into the current smaller oval shape. Sudbury Basin would then be the second largest crater on earth, after the 300 km Vredefort crater in South Africa, and larger than the 170 km Chicxulub crater in Yucatán, Mexico which is linked to the extinction of the dinosaurs.

The deformation of the Sudbury structure occurred in four main deformation events (by age):

the Penokean Orogeny (1900 Ma)
intrusion of the Sudbury Igneous Complex (1844 Ma)
the Grenvillian Orogeny (1400 - 1000 Ma)
the Lake Wanapitei impact (37 Ma)

Throughout the 20th century the origin of the Sudbury Basin was widely disputed^{[citation needed]}.

[edit] Modern uses

The large impact crater filled with magma containing nickel, copper, platinum, palladium, gold and other metals. As a result of these metal deposits, the Greater Sudbury area is one of the world's major mining communities. The region is one of the world's largest supplier of nickel and copper ores. Most of these mineral deposits are found on the outer rim of the Basin. Due to the high mineral content of its soil, the floor of the Basin is among the best agricultural land in Northern Ontario, with numerous vegetable, berry and dairy farms located in the Valley. However, due to its northern latitude, it is not as fertile as agricultural lands in the southern portion of the province. Accordingly the region primarily supplies products for consumption within Northern Ontario, and is not a major food exporter.