UC Berkeley Professor Awarded for Research on Dinosaur Extinction

Before humans were even a glimmer in the eye of evolution, the dinosaurs met a fiery end by meteor-setting the stage for life as we know it. Last week, 65 million years later, a committee of scientists recognized a UC Berkeley professor for piecing together the puzzle.

A group from the Lamont-Doherty Earth Observatory at Columbia University awarded geology professor Walter Alvarez the Vetlesen Prize for Earth Sciences, which honors scientific work enhancing the understanding of the Earth and its history.

The distinction recognizes Alvarez's research on the mass extinction at the end of the Cretaceous period, and includes $250,000 and a gold medal.

G. Michael Purdy, the director of the observatory and chair of the award committee, said Alvarez's theory was important because it revolutionized the idea that major changes on Earth take place slowly and gradually.

"The factor that was key (in the decision) was that his discovery-the Cretaceous-Tertiary boundary, the extermination of the dinosaurs-really changed the way everybody thinks about the evolution of the planet and the evolution of life," he said.

Purdy said the Vetlesen Prize is as prestigious as the Nobel Prize, which does not have a category for earth sciences.

Instead of dinosaurs being gradually replaced by mammals, Alvarez's theory states that a dramatic extraterrestrial impact wiped out much of Earth's life in a short period of time. When he first published his theory in 1980, it was heavily criticized by gradualists.

"There were some people who thought it was a great idea, but there were lots of people that didn't like it all," Alvarez said. "Now you could say that geologists recognize that most things in the earth's past happen gradually, but every now and then, there will be some sort of catastrophic event that changes everything."

In 1977, Alvarez began working on his theory with a team that included his father, Nobel-winning physicist Luis Alvarez.

They discovered a layer of rock from the time of the extinction containing iridium, an element rare on Earth but common in asteroids and meteors. The team theorized that the iridium came from a massive extraterrestrial impact, but they lacked definitive evidence to support their claim.

"The problem was, if there had been a huge impact, then there also ought to be a huge crater," Alvarez said. "But there was a period of 10 years where no one could find the crater."

In 1990, the team finally identified the Chicxulub crater in the Yucatan Peninsula as the site of impact. After the discovery, Alvarez said, most scientists accepted his theory as true and recognized the importance of large, dramatic events in Earth's history.

Alvarez said he now works in "Big Science," which looks at the history of cosmos, earth, life and humanity.

"If you're trying to understand all of history, it's really interesting to know about gradual changes in the history of life and catastrophic ones," he said. "To me, right now the most interesting thing about the extinction work is trying to tie it into a much broader understanding of all of history."

Alvarez's friend and former colleague, integrative biology professor Kevin Padian, said the value of his work also lies in its ability to open new avenues of research.

"(Alvarez) has been tremendously influential in the field. This award recognizes the stimulation of essentially 30 years of research in extraterrestrial influences on Earth's history," Padian said. "Research like his really comes along only a few times in a century."

Tags: GEOLOGY