Finding an abundance of iridium in the K-Pg boundary sequence worldwide pointed to evidence that this layer was of ____ origin.
A) carbon
B) organic
C) geologically recent
D) prehistoric
E) extraterrestrial

Question

Finding an abundance of iridium in the K-Pg boundary sequence worldwide pointed to evidence that this layer was of ____ origin.​
A) carbon​
B) ​organic
C) ​geologically recent
D) ​prehistoric
E) ​extraterrestrial

Quizplus · Accepted Answer

The high levels of iridium found in the K-Pg boundary layer are unusual because iridium is rare on Earth's surface but abundant in asteroids and comets. This evidence supports the theory that the layer was created by an extraterrestrial impact, such as an asteroid or comet hitting the Earth.

Finding an Abundance of Iridium in the K-Pg Boundary Sequence