What Caused the Mass Extinction Recorded at the K-T Boundary?
ESU801  The Chicxulub Impact Crater

In 1980, Luis and Walter Alvarez, Frank Asaro, and Helen Michel proposed that the K-T mass extinction resulted from an asteroid impact. They based their claim on the high levels of the element iridium in the K-T layer. In 1990, Alan Hildebrand and William Boynton discovered, through seismic imaging, a sixty-five million year old impact crater on the northern edge of the Yucatan Peninsula of Mexico.

  !   To find out more about the Chicxulub Crater, read the articles at the links below.

V.L. Sharpton, LPI
Although the Chicxulub crater is buried beneath layers of sediments, gravity and magnetic field data have revealed its three-dimensional structure.
Crater Structure

Chicxulub Impact Event

Liquid Impact

News Article

5. How has the discovery of the Chicxulub impact crater shifted the debate?

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