Asteroid Impact That Killed the Dinosaurs - New Evidence

The idea that a cosmic impact ended the age of dinosaurs in what is now Mexico now has fresh new support, researchers say. The most recent and most familiar mass extinction is the one that finished the reign of the dinosaurs — the end-Cretaceous or Cretaceous-Tertiary extinction event, often known as K-T. The only survivors among the dinosaurs are the birds.

Currently, the main suspect behind this catastrophe is a cosmic impact from an asteroid or comet, an idea first proposed by physicist Luis Alvarez and his son geologist Walter Alvarez. Scientists later found that signs of this collision seemed evident near the town of Chicxulub (CHEEK-sheh-loob) in Mexico in the form of a gargantuan crater more than 110 miles (180 kilometers) wide.

The explosion, likely caused by an object about 6 miles (10 km) across, would have released as much energy as 100 trillion tons of TNT, more than a billion times more than the atom bombs that destroyed Hiroshima and Nagasaki.

 Photo By Don Davis

 Artist’s impression of a 6-mile-wide asteroid striking the Earth. Scientists now have fresh evidence that such a cosmic impact ended the age of dinosaurs near what is now the town of Chixculub in Mexico.

 Photo By [Image courtesy of Klaudia Kuiper]

  Rock layers near Jordan, Mont., exposing the level (lower arrow) where the dinosaurs and many other animals and plants went extinct. The arrows point to coal beds which contain thin volcanic ash layers that were dated.

Photo By Image courtesy of Paul Renne

 Doctoral student Bill Mitchell collecting a volcanic ash sample from the coal bed just above the final dinosaur extinction level.

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