Geologist Questions Mass Extinction

 

By Stephen B. Collins '74
Photography by Courtesy of Robert Gastaldo
 

Geology majors Marcy Rolerson ’06 and Daniel Pace ’06 working with Professor Robert Gastaldo on the Cape of Good Hope in South Africa.
Geology majors Marcy Rolerson ’06 and Daniel Pace ’06 working with Professor Robert Gastaldo on the Cape of Good Hope in South Africa.

An article written by Robert Gastaldo, chair of the Geology Department, with two Colby undergraduates among the coauthors, undermines a popular and widely publicized theory about the Permian Mass Extinction, the greatest catastrophic dieoff of animals in Earth’s history.

“Instead of a sudden crisis, the largest mass extinction in Earth’s history might have been a prolonged event that stretched over hundreds of thousands of years,” is how the American Association for the Advancement of Science’s (AAAS) magazine reported the story online. “If confirmed, the findings could send researchers scrambling to find a new explanation for the greatest of mass die-offs on land.” Big news in the world of science.

The article in the March 2009 GEOLOGY magazine, the leading journal in the discipline, challenges the theory that a “dead zone” layer of sedimentary rock in central South Africa represents the clear and synchronized end of most animals from the Permian period—a theory championed by other scientists on the Discovery Channel, in National Geographic specials, and on Animal Planet.

The Colby researchers, working with two other scientists and funding from the National Science Foundation, found wide variations in the stratigraphic record at sites very near where the original layer dubbed “the dead zone” was discovered. The variations undermined the notion that it was a consistent marker of a relatively quick die-off across an area spanning continents.

C. Kittinger “Kit” Clark ’08 and Sophie Newbury ’08 are coauthors, and about a dozen Colby students have worked on site in the Karoo Basin of South Africa since 2003, when Gastaldo was invited by the Smithsonian to study rocks in the area. The first two science writers to report the story online both made the same mistake: calling Newbury and Clark “graduate students,” when, in fact, they published the paper as undergraduates.

Read the full article in GEOLOGY magazine.

 
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