Meteor Linked to Extinction

A layer of rock as thin as a finely honed knife blade has led researchers to conclude that a meteor impact is responsible for a massive global extinction 380 million years ago, similar to the one that wiped out the dinosaurs.

Brooks B. Ellwood, chairman of the department of geology and geophysics at Louisiana State University, and his colleagues proposed in an article published Friday in the journal Science that a large rock smashed into what is now the Moroccan desert, resulting in the death of as many as 40% of all sea creatures.

Ellwood and his colleagues examined layers of earth from the area, all of which showed evidence of a collision: a thin layer of deformed crystals along with rocks of unusual chemical composition. That layer was sprinkled within another layer showing the sudden extinction and subsequent emergence of new marine life forms.