Vredefort crater
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Vredefort_crater.jpg
Vredefort crater is the largest known impact crater on Earth. Located in the Free State Province of South Africa, the town of Vredefort is situated in the crater. The site is also referred to as Vredefort dome or Vredefort impact site.
Formation and structure
The bolide that hit Vredefort is one of the largest to ever impact Earth, estimated at over 10 km (6 miles) wide. The crater has a diameter of roughly 300 km (186 miles), larger than the 250 km (155 miles) Sudbury Basin, and the 170 km (106 miles) Chicxulub crater. The age is estimated to be over 2 billion years (2023 ± 4 million years), impacting during the Paleoproterozoic era.
Valhalla_crater_on_Callisto.jpg
The Vredefort crater site (27° 0′ S, 27° 30′ E) is one of the few multi-ringed craters on Earth, though they are more common on the Moon. Geological processes, such as erosion and plate tectonics, have destroyed most multi-ring craters on Earth.
It was originally thought that the dome in the center of the crater was formed by a volcanic explosion, however in the mid 1990s evidence revealed that it was the site of a huge bolide impact, with telltale shatter cones often discovered in the bed of the nearby Vaal River.
External links
- Earth Impact Database (http://www.unb.ca/passc/ImpactDatabase/)
- Deep Impact - The Vredefort Dome (http://www.hartrao.ac.za/other/vredefort/vredefort.html)