 In 2010 the American Quaternary Association held a debate between skeptics and supporters in Laramie, Wyoming.In 2011, a large group of scientists challenged the Younger Dryas impact hypothesis on the basis of claims that most of the conclusions could not be reproduced and were a misinterpretation of data.The article claimed that no nanodiamonds were found and that the supposed carbon spherules could be fungus or insect feces and included modern contaminants.