I agree J.D., which I why I placed both elements in my illustration 8) <br><br>-Paul

Two points worth remembering when pondering mass extinctions and their causes:<br><br>1) Demonstrating co-incicidence between a mass extinction and some physical event is not a demonstration of cause-and-effect. Plenty of evidence is consistent with a K/T bolide impact, and the Deccan traps are well known. Proving that either a bolide impact, or Deccan volcanism directly resulted in ecological collapse is a sticky scientific issue that remains unresolved.<br><br>2) Any hypothetical "kill mechanism" must explain the total pattern of extinction and survivial during an extinction event. In the case of the K/T event, the media hyper-focus on "what killed the dinosaurs" oversimplifies a very complex pattern of ecosytem stress during the very late Cretaceous Period. When one looks at the "big picture," finding a simple (and scientifically plausible) answer to "what killed the dinosaurs" is not so simple.<br><br>Regarding the upcoming talk at GSA: the approach of the research seems novel and potentially insightful. However, the stratigraphic record generally cannot be resolved in the temporal detail needed to reveal a "catastrophic" event that occurred in days or months. The contribution made by this research will be more evident when it is published in a peer-reviewed journal. The criteria for presenting a talk at a GSA meeting is not nearly as rigorous as the criteria for publication in a top-tier journal. For myself, I view this presentation as very interesting and potentially insightful, but still preliminary until it has been fully scrutinized by the geo-scientific community.<br><br>Jack Beuthin