The high concentration of iridium at the Cretaceous Tertiary boundary may be attributable to
A)a worldwide rise in sea level.
B)meteorite bombardment.
C)an out flux of iridium from Earth's interior.
D)none of the above

Question

Quizplus · Accepted Answer

The high concentration of iridium at the Cretaceous-Tertiary (K-T) boundary is widely attributed to meteorite bombardment. Iridium is rare in the Earth's crust but abundant in meteorites, and its presence at the K-T boundary supports the theory that a large meteorite impact occurred at that time, contributing to the mass extinction event.

The High Concentration of Iridium at the Cretaceous Tertiary Boundary