The SciencesDeeper ImpactWas yet another mass extinction the work of an asteroid?By Sarah Simpson on May 1, 2001Advertisement Rights & Permissions ABOUT THE AUTHOR(S)Recent Articles by Sarah SimpsonAfghanistan: Rare Earth Elements Could Beat the Taliban [Slide Show]Afghanistan Holds Enormous Bounty of Rare Earths, MineralsAfghanistan's Buried Riches