Skeptics doubt, however, that the impact and the mass extinction at the end of the Cretaceous time related. Instead, they suspect the cause in what is now India, the so-called Dekkan-Trapp, where at that time there was an active super-volcano that emit large amounts of dust, sulfur, and volcanic gases for over 1.5 million years. However, Peter Schulte from the University of Erlangen and his colleagues have now been able to refute this: The decrease in the quantity and diversity of fossils followed the rise of iridium in the rock so abruptly that the continuous volcanic activity could not have been the trigger? especially because in the 500, 000 years before only slight changes took place. In addition, the frequently expressed thesis that the impact occurred much earlier than the mass extinction, from a misinterpretation of geological data: The impact had the layers in the affected area so confused that they could hardly provide reliable information, the researchers said.
According to them, the scenario after the impact looked like this: The impact triggered immediately devastating pressure waves and a heat pulse, which propagated for long stretches. The continental shelves collapsed, causing earthquakes with a magnitude greater than eleven on the magnitude scale (Mw) and a series of tsunamis. At the same time, huge amounts of dust, soot, rocks and gases were spewed into the atmosphere in just a few minutes, spreading all over the earth, causing acid rain and darkening. The subsequent cooling and the lack of light in turn decimated the surviving plants and thus all dependent animal species.Peter Schulte (University of Erlangen) et al .: Science, Volume 327, page 1214 ddp / science.de? Ilka Lehnen-Beyel advertisement