A favored theory to explain the extinction of dinosaurs, together with many other species, has been the globally catastrophic collision of a large asteroid with the Earth. Supporting evidence is an extraterrestrial chemical element in a layer of dust found worldwide at a geological level laid down contemporaneously with the supposed event. A new competing theory contends that any asteroid impact was irrelevant, because it was massive volcanic activity that caused the extinctions by putting enough dust into the atmosphere to cool the planet. The Deccan region of India contains extensive volcanic flows that occurred within the same time period as the supposed asteroid impact and the extinctions. The new theory assumes that ['the massive volcanic activity was not caused by the impact of an asteroid', 'the extinctions took place over a longer time period than they would have if caused by the impact of an asteroid', 'no individual dinosaurs survived the impact of the asteroid, if it occurred', 'it is not possible to determine which would have occurred first, the volcanic flows in the Deccan region or the supposed impact of an asteroid']