Italy's geologic history becomes a personal tale in Walter Alvarez'...(ries sprinkled throughout Italy. The qua...)

"If you travel around in Italy and look at the buildings, you will see that the Italians just love ornamental stone," Alvarez said. "Even if you wander around San Francisco and look at the storefronts, you will see limestone and marble from all over Italy, as well as granites and schists."

Alvarez's own research, in particular the work in collaboration with Bill Lowrie using magnetic signatures left in sediments to date rocks, has helped reconstruct some of this Italian history.

After the Apennines appeared about 40 million years ago, in the Eocene, the continental plate known as Adria, which carried the mountain chain, collided with the European continent, shoving an even more ancient sea floor several miles up to form the Alps. Alvarez's research has helped validate the theory behind this - plate tectonics - which holds that the surface of the Earth is covered by a jigsaw puzzle of continental and oceanic plates that move around, generating mountains where they collide.

Alvarez acknowledges that most people overlook rocks in favor of ever-changing trees, flowers and wildlife, but the unchanging nature of rocks is what drew him into geology.

"What makes rocks so wonderful is the fact that they barely change at all, and as a result, they... preserve the way they formed, whether a million years ago or a thousand million years ago," he said "We simply wouldn't know anything about what happened beyond human memory or writing if it wasn't for having things recorded in rocks. They are history books, and quarries are like libraries."

Raised in Berkeley, Alvarez earned his Ph.D. from Princeton University in 1967, worked for oil companies in the Netherlands and Libya, applied his geological knowledge to uncovering the archeology of ancient Rome, and later worked at the Lamont-Doherty Earth Observa
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