The Triassic-Jurassic Extinction

214 million years ago an asteroid hit what is now Canada. Now the crater is a ring-shaped reservoir 70 kilometers in diameter: Manicouagan Reservoir.

Did this impact cause a mass extinction? The asteroid was 5 kilometers across, while the one that killed the dinosaurs much later was 10 kilometers across. But this is still huge!

For a while people thought this impact may have caused the Triassic-Jurassic mass extinction event. But now that the crater has been carefully dated, they don’t think...