The ultimate Explosion, and maybe the Reason that Dinosaurs are not longer with us

Palaentologists and Geologists have long scratched their head to explain why every teen's favourite pets have suddenly become extinct a couple of million years ago, but a truly convincing reason has never been found. The current theory that a large meteorite hit the earth and in conjunction with massive volcanic activity (called flood basalt) reduced animal life is pretty convincing but has a slight snag:
In the past 400 million years there have been four mass extinctions: ca 380 million years ago the Frasnian-Fammenian extinction pulses reduced marine life by 60 percent, followed by a huge die-off of ca 96 percent of all species at the end of the Permian 251 million years ago. Next was mass-extinction at the end of the Triassic (201 million years ago) and last but not least 66 million years ago at the Cretaceous-Tertiary boundary.
Now, how likely is it that every time there's a continental flood basalt there's this huge meterorite hitting earth? Not very. Apparently the likelihood of both events happening simultaneously in the last 400 million years is 1 in 3500. So, a different explanation needs to be explored.

Enter Geomar, a team of scientists from the University of Kiel, in Germany, giving the world a new theory: Maybe these large craters (associated until now with meteorite impacts) and the continental flood basalts all stem from the same source? Continental flood basalts are assumed to appear when mantle plumes well against the continental lithosphere and breaking through it, causing widespread dramatic vulcanic activity. But what would happen if the mantle plume would hit a Craton, extremely tough, stable and deep chunks of the lithosphere? The plume would move sidewards and pool under the thinnest area of lithosphere, while under the craton there would still be the main magma pool, stockpiling gases. Now, when the craton starts to pull apart, a huge explosion would be triggered, releasing the pressure below the craton, spewing toxic gases and large chunks of matter into the atmosphere (causing huge craters where it comes down) and causing a magnitude 11 earthquake. The combination of these factors would be enough to cause a devastating impact on the planet's biosphere. The mechanism reminded Phipps Morgan, the head honcho at Geomar, of Jules Verne's From the Earth to the Moon which is about a huge gun that shoots objects into space, hence the name Verneshot. Morgan is convinced that his theory could explain the Chicxulub crater and even the mysterious Tunguska event in 1908.

Now that would not go down well with the UFO theorists....


Source: "Four days that shook the earth", Kate Ravillious, New Scientist 8.5.2004, pp 32-35

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