Volcanism the cause of the Cretaceous Mass Extinction?

The debate regarding the principle cause of the Cretaceous mass extinction event some 65 million years ago is about to re-opened with the airing of a television programme claiming that massive volcanic eruptions on the Indian sub-continent were the real cause of the extinctions not the impact of an ex-terrestrial object.

US Geosciences professor Gerta Keller of Princeton University and her research colleagues have submitted a theory stating that the dinosaurs gradually died out as a result of climate change, induced by huge volcanic eruptions.

Professor Keller bases her theory on her National Science Foundation-funded field work in India and Mexico that uncovered geological evidence that the mass extinction and the meteor impact occurred at different times.  The Chicxulub event is believed to have taken place approximately 300,000 years before the extinction.  Keller and her colleagues believe that the impact event could not be the main cause of the mass extinctions, the timing is all wrong.

However, other leading writers and scientists still support the work of Luis and Walter Alvarez, an American father and son team who first published the discovery of a global K-T boundary with high levels of iridium and theorised on a catastrophic meteor or asteroid impact devastating life on Earth.  Exponents of the meteor impact theory have even stated that there may have been two impacts – 300,000 years apart that led to the demise of approximately 70% of all life on the planet.

The Deccan Traps, the “smoking gun” of Keller’s theory did release an enormous amount of green house gas into the atmosphere and eruptions took place for millions of years.  Volcanism on this scale would certainly have affected the climate, whether or not this was the main factor or a contributory one to the demise of the dinosaurs is still hotly debated.

We suspect this will run and run.

To read more about the Deccan Traps: Blame the Deccan Traps

To read more about the ex-terrestrial impact theory: Geologists get to the bottom of the Chicxulub impact crater

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