The end-Permian extinction probably isn't as well known as the Cretaceous extinction that wiped out the dinosaurs some 65 million years ago. But the end-Permian collapse nearly spelled the end of life on Earth.

Now scientists have painted a picture of just how fast the "Great Dying" unfolded 252 million years ago (prehistoric time line).

(Related: "The Permian Extinction—When Life Nearly Came to an End.")

While the causes of the Permian extinction remain a mystery, from here on out, any theory must be compatible with a 200,000-year time frame centered around 252.28 million years ago, the authors assert. This time span is span indicated by analysis of fossils and chemical evidence of changes in Earth's carbon cycle in rocks from