Although the theory in this cartoon is not one of them (after Gary Larson), there are a number of alternatives to the baked-by-returning-debris-from-the-impact theory we have discussed in the main lecture. They include that the impact caused widespread climate change, that it led to a period of enhanced volcanic activity, or that climate change not related to it was the primary cause of the mass extinctions.
Image from http://www.cocs.com/imagegallerydetail.asp?ImageID=3,
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