"These impacts were very large. They really changed the course
of the evolution on Earth," he said.
The report does not say what changes the impact might have
"There isn't a big extinction event you can identify [that is]
as cut-and-dried as the extinction of the dinosaurs," said
co-author, Donald Lowe.
'Incredible [tidal waves]'
Mr Lowe said it would have taken the rock less than two seconds
to pass through the ocean and slam into the sea bed.
"That would generate enormous waves kilometres high that would
spread out from the impact site, sweep across the ocean and produce
just incredible tidal waves - causing a tremendous amount of erosion
on the microcontinents and tearing up the bottom of the ocean," he
Geologists found traces of the meteorite in South Africa's
Barberton greenstone belt and Pilbara block in western Australia.
The sites contain rocks formed more than three billion years ago
and which contain information dating back to the beginning of the