Scientists suggest a new, earth-shaking twist on the demise of the dinosaurs

By Joel Achenbach October 19

 

 

An illustration of the Chicxulub impact on the Yucatan Peninsula in Mexico, seen from 100 kilometers (km) altitude. (D. van Ravenswaay/Photo Researchers, Inc)

New research suggests that the asteroid or comet that slammed into the Earth 66 million years ago rocked the planet so violently that it accelerated a massive volcanic eruption in India, a double catastrophe that wiped out the dinosaurs and 70 percent of the Earth's species.
The study, published Thursday in the journal Science, puts a twist on the consensus explanation of the mass extinction at the end of the Cretaceous period. Scientists have long been confident that a mountain-sized object crashed into the planet, leaving traces even today of a vast crater at the tip of Mexico's Yucatan peninsula.
[Don’t worry. Matt Damon won’t get stuck on Mars. NASA can’t get him there.]
They’ve also known that massive volcanism in India was happening around the same time, spreading lava across a huge region known as the Deccan Traps. The coincidence of those two events initially hinted at causality, but subsequent dating of the Deccan Traps formations indicated that the flood of basaltic lava began long before the cataclysmic impact.

With the new data, causality's once again in play. The asteroid or comet didn’t cause the initial eruption, but it could have intensified it, according to the paper.
The Chicxulub impact – named after a town in the Yucatan – created earthquakes of magnitude 11 in the vicinity of the crater, the authors say. Magnitude 9 earthquakes would have been felt around the planet, they say.
[A ‘lost world’ of dinosaurs thrived in the snowy dark of Alaska]
The seismic energy made the planet's crust more permeable. Molten rock deep in the interior began flowing through fractures. As that magma expanded, gasses in the solution began forming bubbles. As with a shaken soda bottle, the results were likely explosive.
“Once that’s initiated, it becomes a kind of runaway process,” said Paul Renne, a University of California, Berkeley geologist and lead author of the new paper.