Chapter 4 ( Monique Proverbs)

In chapter 4 , Walter Alverez has found traces of asteroid dust in a thin layer of Gubbio. Due to the way limestone is made up it contradicted both Lyell and Darwin’s theory that extinction happened gradually. There was a large amount of Iridium in the clay samples which meant that there was an asteriod. This was the kind of catastrophic event that would cause an extinction somewhat like the mastodon bone that was found. This hypothesis that an asteriod had hit the earth was supported by a quarts in the clay layer which was produced by high pressure. Also many land animals died from this like dinasours and birds. A quote that stuck out to me from this chapter was “Mass extinctions were not to be confused with catastrophes”. To counter that my question is if a metor hits the earth it’s considered a catastrophe and can lead to extinction. If mass extinction isn’t to be confused with catastrophes can they be related? For example a catastrophe could lead to an extinction.