Question

Describe the evidence for the cause of the Cretaceous–Paleogene (K–Pg) mass extinction.

Short answer

The hypothesized cause of the K-Pg extinction event is an asteroid impact.

Step-by-step solution

Step 1. Introduction 

TheCretaceous–Paleogene (K–Pg) extinction event was a sudden mass extinction of three-quarters of the plant and animal species on Earth.

The K–Pg extinction event was severe, global, rapid, and selective, eliminating a vast number of species. Based on marine fossils, it is estimated that 75% or more of all species were made extinct.

Step 2. Explanation 

• The first piece of evidence of the impact is a spike in iridium (an element that is rare on Earth, but common in meteors) in the geological layers that mark the K–Pg transition.
• The second piece of evidence is an impact crater off the Yucatán Peninsula that is the right size and age to have caused the extinction event.