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Article: The call of catastrophes. (influence of mass extinction theory on future science)(75th Anniversary Supplement)
- Article from:
- Science News
- Article date:
- March 1, 1997
- Author:
CopyrightCOPYRIGHT 1997 Science Service, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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In the fall of 1973, a young geologist named Walter Alvarez explored a limestone gorge just outside the medieval walls of Gubbio, Italy. Chipping away at the layers of rock with his hammer, Alvarez stumbled onto something that would revolutionize how scientists view our planet and the history of life.
Alvarez, together with his father, Nobel prizewinning physicist Luis W. Alvarez, and two other researchers at the University of California, Berkeley, discovered a pencil-thin layer of clay containing unearthly amounts of the element iridium. In 1980, the team interpreted the iridium layer as evidence that a huge comet or meteorite slammed into Earth 65 million years ago ...