The East Warburton Basin in
South Australia
South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...
is the site of a hypothesised large
impact crater
An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...
of the
Carboniferous period (around 360-300 million years ago). The subterranean structure lies buried at a depth of ~4 km, and measures a minimum of 200 km in diameter. For comparison, the
Chicxulub crater
The Chicxulub crater () is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is offshore near the community of Chicxulub, after which it is named. It was formed slightly over 66 million years ago when a large a ...
, which caused the
Cretaceous–Paleogene extinction event
The Cretaceous–Paleogene (K–Pg) extinction event (also known as the Cretaceous–Tertiary extinction) was a sudden mass extinction of three-quarters of the plant and animal species on Earth, approximately 66 million years ago. With the ...
, is about 180 km in diameter. The East Warburton crater is adjacent to the West Warburton crater, which is also around 200 km in diameter. Combined, they make up the largest known impact zone on Earth, but individually, are smaller than the largest in the world, the 300 km wide
Vredefort impact structure
The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, was around across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is loca ...
in
South Africa
South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. It is bounded to the south by of coastline that stretch along the Atlantic Ocean, South Atlantic and Indian Oceans; to the ...
. The Warburton craters formed when an asteroid or comet, on a collision course with Earth, split into two main pieces and impacted the
Australian continent
The continent of Australia, sometimes known in technical contexts by the names Sahul (), Australia-New Guinea, Australinea, Meganesia, or Papualand to distinguish it from the country of Australia, is located within the Southern and East ...
, then part of the
Gondwanan supercontinent.
Scientists proposed the impact formation through analysis of
shocked quartz
Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. Under intense pressure (but limited temperature), the crystalline structure of quartz is deformed along planes inside the crystal. These pl ...
grains from the area after a circular anomaly appeared in
seismic tomography studies of the region.
Geophysical anomalies and quartz microstructures, Eastern Warburton Basin, North-east South Australia: Tectonic or impact shock metamorphic origin?
''Tectonophysics'' Vol. 589, 18 March 2013, Pp. 57–76. Retrieved 15 May 2013.
See also
* Cooper Basin
The Cooper Basin is a Permian-Triassic sedimentary geological basin in Australia. The basin is located mainly in the southwestern part of Queensland and extends into northeastern South Australia. It is named after the Cooper Creek which is an ...
* List of possible impact structures on Earth
This is a list of possible impact structures on Earth. More than 130 geophysical features on the surface of the Earth have been proposed as candidate sites for impact events by appearing several times in the literature and/or being endorsed by the ...
References
{{Reflist
Carboniferous impact craters
Far North (South Australia)
Impact craters of South Australia