Question

compile a list of the evidence supporting the impact hypothesis as the cause of the cretaceous mass extinction.

Answer 1

http://mygeologypage.ucdavis.edu/cowen/~GEL107/KT.html
Look on this page under the heading "An Asteroid or Cometary Impact?" It has some great information about the evidence that supports the impact hypothesis. Go through it, and whenever you see something that supports the idea that an asteroid hit the earth, jot it down. By the end of the section, you'll have a pretty good list! :)

Answer 2

Tell me if you have any trouble making the list though and I can help walk you through it :) @christinalee

Answer 3

Evidence for a bolide impact being the main cause of the K-T event is a worldwide iridium anomaly and spherules, among others (Google it - there's plenty of info on the Cretaceous extinction). This same evidence has been presented as representing a volcanic cause (Google Deccan traps); however, volcanoes generally do not cover much geographical area and probably would not produce such a consistent iridium layer over the entire earth. I would say bolide impact is most likely, but it is also likely that a number of factors contributed to the mass extinction. By studying extinction patterns in various organisms you can deduce the proximal causes, and from those guess at the ultimate causes.