Meteor Flipped Earth’s Crust
Inside-out
About 1.8 billion years ago a huge meteorite crashed into what is now Sudbury, Ontario. The impact was so violent that it flipped parts of the earth’s crust inside out, spewing melted rock and a scattering of precious metals from deep inside the ground around the top of the impact site, according to research by a University of Toronto professor.
 A study published by Dr. James Mungall in the scientific journal Nature reveals that the ancient crater was filled both by melted rock from 20 to 40 km below the earth’s crust and the valuable metals such as nickel for which Sudbury is known.
This discovery, which came after analyzing rocks from different layers of the impact site, also turned up another interesting fact: Elements most likely from the meteor are found only along the top layer of the site, indicating that it probably vaporized in a great burst of heat on impact rather than being deposited deep in the ground.
This inside-out effect happened when the meteor, which measured 10 km in diameter and still extended above the atmosphere when its front edge first hit the surface of the earth, created an impact like the one made by a drop falling into a glass of milk.
“It formed a bowl-shaped impression, but that quickly leveled out,” Dr. Mungall says, adding that this effect would probably have taken a few minutes. “Part of that process involves material shooting out, like the small droplets that form around the drop of milk – the impact stirred up the crust in a big way.”
These findings provide scientists with valuable clues about how the earth formed and evolved.
“We see the earth’s crust being turned up on the scale of tens of kilometres, but the impacting meteorite did not mix into the ground,” Dr. Mungall says.
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