Chapter 29, Problem 12TE

How does the element iridium relate to the time of the extinction of the dinosaurs?

To determine

The relation between the element iridium and the time of the extinction of the dinosaurs.

Answer to Problem 12TE

The iridium containing meteorite caused the extinction of dinosaurs.

Explanation of Solution

Iridium is an element that is rarely found on Earth. But, it is plentifully found in meteorites. The study of rocks has provided evidence for the deposition of iridium containing sediments during the Cretaceous period. Thus, it is an accepted hypothesis that meteorites caused the extinction of dinosaurs that lived in the Cretaceous period.

The fall of meteorites on Earth resulted in the generation of earthquakes. Huge amounts of heat were also released during the meteorite impact. A dust cloud formed as a result of meteorite impact hindered the sunlight necessary for photosynthesis. A lack of food supply resulted from the stopping of photosynthesis. The extreme cold and lack of food supply due to the cloud eventually led to the extinction of dinosaurs and other reptiles. Thus, iridium containing meteorite caused the end of the Cretaceous period and the dinosaurs that lived during the period.

Conclusion:

Therefore, the iridium containing meteorite caused the extinction of dinosaurs.