Prof Note

DINO WARS: THE STORY CONTINUES

A DOING AMMUNPION TO AN increasingly accepted theory. a couple of Dartmouth goechemists recently reported that global warming may have contributed to the extinction of the dinosaurs.

For years, scientists speculated that many extinctions might have been caused by a catastrophic impact sometime between die Cretaceous and Tertiary periods some seven million years ago. Until recently, though, scientists agreed to disagree on which crater may have resulted from such a cataclysm.

Cobbling together geological clues Joel Blum and C. Page Chamberlain showed how the comet or asteroid that caused the crater located near the Mexican town of Chicxulub could well have spewed enough of the Lithosphere into theair to radieally alter the earth'stignnate. Thetwo published their finding in Science.

I Meanwhile, across the hall, Dartmouthgeologists Charles Drake and Charles Officer work diligentlyto disprove theircolleagues'hypothesis.Drake and Officer are prominent proponents of another respected extinction theory: that dinosaurs and other species fell victim to more gradual climatic changes caused by changing ocean patterns, volcanic action, and changes in the sea level. [See our February '88 cover story, "Dino Wars."!

Drake (l.), Officer

Chamberlain (l.), Blum