New Impact crater (Introduction)
Another impact crater found in Iowa, from about 470 million years ago:-http://www.washingtonpost.com/national/health-science/crater-found-in-iowa-points-to-asteroid-break-up-470-million-years-ago/2013/02/18/545131f8-76d5-11e2-aa12-e6cf1d31106b_story.html?wpisrc=nl_headlines
New Impact crater:extinctions
How to kill off life with meteorite impacts;-http://blogs.scientificamerican.com/history-of-geology/2013/02/17/mass-extinctions-and-meteorite-impacts/?WT_mc_id=SA_DD_20130219
A recent extinction event understood
Large animals in No. America disappeared at the end of the last ice age, roughly 14,000 years ago due to an impact in no. America:-http://www.sciencedaily.com/releases/2013/05/130520185524.htm-http://phys.org/news/2013-05-comprehensive-analysis-impact-spherules-theory.html