Earlier Mass Extinction also caused by meteorite

Deep in the layers of the Earth, ancient rock shows signs of a planet, 250 million years ago, teeming with plants, fish, reptiles and proto-mammals . Then, evidence of life around the globe all but vanishes.

IN A MERE 100,000 years, a blink of the eye in geological terms, 90 percent of the earth’s life disappeared. Now, an analysis of meteorite fragments described in this week’s Science magazine helps confirm one scenario—that space rock crashed into the earth at the end of the Permian period, devastating the environment in a catastrophe much like the one that wiped out the dinosaurs 185 million years later.