Events of Mass Destruction

[George Blasing <dinoworld@msn.com>]

In your studies have any of you come across evidence of any dramatic 
environmental events trapped in the fossil record?

I?m thinking about things like the event that created the Ashfall fossil 
beds, the Chixalube crater, major volcanic events, the building of mountain 
ranges, etc?

Are there any other big events that have occurred in our past that you are 
aware of?

Thanks for your help

George