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PALEONEWS: Methane Explosion Theory City for Dinosaur Demise



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http://dailynews.yahoo.com/h/nm/19991117/sc/science_dinosaurs_1.html

Wednesday November 17 1:32 PM ET 

Methane Explosion Theory City for Dinosaur Demise

LONDON (Reuters) - A vast methane firestorm ignited when a huge asteroid
struck the Gulf of Mexico 65 million years ago could have hastened the
demise of dinosaurs on earth, New Scientist magazine said Wednesday.

Such an impact, the theory goes, would have sent shockwaves around the
planet, possibly unleashing methane trapped in seabed sediment and
setting the atmosphere ablaze.

``This could have contributed to the demise of the dinosaurs,'' Burton
Hurdle of the U.S. Naval Research Laboratory in Washington, told the
weekly science magazine.

Hurdle and his colleagues believe lightning in the atmosphere could have
ignited the gas.

They suggest that vast quantities of rotting vegetation trapped in
sediment far below sea level combined with water to form solid methane
hydrates in the low temperature and high pressure environment.

``As further evidence, the researchers point to an earlier discovery of
disruption in late Cretaceous sediments (about 65 million years ago),
possibly due to methane release at Black Ridge off the coast of
Florida,'' the magazine added.

Other scientists found the theory interesting but flawed.

``I think this idea is very intriguing,'' said Peter Schultz of Brown
University in Providence, Rhode Island. ``But I'm not sure even an
impact this big would have liberated that amount of methane.''

Evidence is mounting that it was an asteroid strike that led to the
extinction of dinosaurs. One theory is that the impact of the asteroid
kicked up dust clouds that blocked sunlight and plunged the planet into
many years of continuous winter that the dinosaurs were physically
unable to survive. 

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