Extinction:

At the end of the Mesozoic Era and the beginning of the Cenozoic Era (Cretaceous-Tertiary/K-T boundary) more than half of all plant and animal species died out (Lemon, 1993).

Due to controversial debates in the scientific community over the cause, the end-Cretaceous mass extinction has generated considerable public interest.

One hypothesis suggests that a large extraterrestrial body, i.e., meteorite, or comet, approximately 10km in diameter collided with the earth (Lemon, 1993).

A collision of this magnitude would have produced a cloud of dust in the atmosphere, obscuring the sun, causing widespread decimation of photosynthetic organisms.

This in turn would cause many food chains to collapse, resulting in mass extinction through a wide spectrum of organisms, including the Ceratopsians and all other dinosaurs.

Recent research suggests that the impact site may have been in the Yucatán Peninsula of Mexico (Lemon, 1993).

(Geological Survey of Canada, 1996)

A perspective plot of the Chicxulub crater with a cutaway view showing a cross section of the crater as revealed by seismic reflection data. This view is looking to the south; the Yucatán coastline is shown by a thin dark line.