When we think of mass extinction, we tend to think of the asteroid impact that killed the dinosaurs 66 million years ago. That impact and its following mass extinction might not have been singular events. Australian scientist Dr. Andrew Glikson discovered twin asteroid impacts in Australia that may be ten times older than the dinosaur extinction. He has a theory that asteroid impacts throughout the history of the earth actually changed the way our planet and its species evolved, as each impact would have created an extinction and divergent species.
The impact scar is so deep, that it deformed deep layers of rock near the earth’s molten mantle, forging metallic bulges in the earth’s crust that create magnetic and gravitational anomalies. That’s right, in this section of Australia’s Warburton West Basin your compass would be useless and the earth’s gravitational field would be slightly off as well, like a spooky, desert Bermuda Triangle down under.
By using method dating the surrounding rocks, Dr. Glikson believes these impact scars are from two asteroids that hit the earth between 300 million and 600 million years ago. The asteroid impact believed to have killed the dinosaurs hit 66 million years ago. The resulting dust cloud blocked out the sun and sent ash particles back down to earth, leaving an ashy sediment layer that can be found around the world. The Australian asteroid in question has no correlating sedimentary layer, leaving Dr. Glikson without additional evidence of these asteroids’ mass extinction.
Glikson believes the twin asteroids may have measured 10 km across, from measuring deformations in the earth’s crust. Usually when these scientists find an asteroid impact scar as large as this, they can tie the date to an extinction. Extinctions aren’t rare or singular. We tend to think that there was one extinction that killed off the dinosaurs, but our planet may have actually endured successive rounds of extinctions on a smaller scale.
Source: Australian National University