article_snippet: Two underground craters measuring 400km together in size have been discovered in central Australia, sparking the possibility of a previously unknown asteroid impact event 300 million years ago that caused many species to go extinct.
article_snippet: a 400km impact zone was found in the Warburton Basin in two parts, each 200km wide, indicating the meteor that created them split into two before smashing into the earth.
article_snippet: Even though a 400km impact zone was found two kilometres underground, a 400km impact zone is now the largest in the world, by over 100km.
article_snippet: We cannot define a 400km impact zone in anywhere near the degree of detail we can define the ones exposed on the surface,' Dr Andrew Glikson from ANUtold Daily Mail Australia.
article_snippet: The two adjoining craters were thought to have been caused when a meteor split on a meteor approach to the Earth, forming two smaller ones each about 10km across.
article_snippet: a 400km impact zone, if confirmed, would be the largest in the world.
article_snippet: The second largest is the Vredefort crater in South Australia, spanning 300km.
article_snippet: a 400km impact zone survives on the surface of the Earth and therefore is easier to find than those underground.
article_snippet: a 400km impact zone was found in the Warburton basin in Central Australia and spans 400 kilometres .
highlights_snippet: Two meteros each 10km across left a 400km impact zone in Australia .
  
highlights_snippet: A team of researchers found the crater two kilometres underground .
  