nsf.gov – Volcanoes, Not Asteroid, May Have Taken Out the Dinosaurs

Comments
Posted at 2008/12/09/1839 by placidwater
(show tags and categories)

RTFA: http://www.nsf.gov/discoveries/disc_summ.jsp?cntn_…

Visual of Volcanoes Exterminating the Dinosaurs

The dinosaurs died gradually from climate change caused by a series of severe volcanic eruptions in India at the end of the Cretaceous period, says Gerta Keller, professor of geosciences at Princeton University. This theory contradicts the long-held notion that the dinosaurs died due to climate change when a giant meteor hit the Yucatan region of Mexico.

Keller’s theory has not yet been adopted by the broader scientific community, but it is rapidly gaining traction as she and her colleagues, funded by the National Science Foundation, report findings from their field work in India and Mexico. The most significant finding is geologic evidence that the mass extinction and the impact of the giant meteor occurred at two different times.

“The Chicxulub impact hit the Yucatan about 300,000 years before the mass extinction that included the dinosaurs and therefore could not have caused it,” Keller says. “We know the age of impact because my team discovered a layer of tiny glass melt-rock spherules in Mexico and Texas.” The spherules formed when the rocks were vaporized by the impact and blown into the stratosphere–and then rained down over North and Central America. “This glass spherule layer marks the precise time of the impact 300,000 years ago,” she notes.

The sediments and fossils in the older sediments below the spherule layer and younger sediments above it reveal how life was affected by the impact.

“We see no change, not a single species died out, so the mass extinction 300,000 years later must have been caused by another catastrophe,” Keller says. She’s firm in her belief that the other catastrophe was a series of volcanic eruptions in the Deccan Traps, a volcanic mountain range that covers much of India today. The mountains, which today are 12,000 feet high, were much higher in prehistoric times.

“Volcanic eruptions poured out lava flows after lava flows, stacking them like a layer cake,” she says. “The total volume in cubic miles was greater than the Rockies and the Sierras combined.”

Whoa!!! Wait … oh yes: Whoa!!!!!! I bet some old school archaeologists are steaming. Now THIS is news!

The photo is pure gold too, for that matter. Photo credit goes to Zina Deretsky.

more recent post
older post
  • I don't care if what is the real reason why dinosaurs are extinct now.. I'm glad and thankful that there is no dinosaur today..
  • Dickson -> RTFA. If you read the article from nsf.gov, you will find that they carbon dated the layers of melted glass associated with the Chicxulub impact to be ~300,000 years prior and many layers of earth below the fossilized remains of the dinosaurs. Who knows about the volcanoes (although a layer of magma coincides with the dinosaur remains), but it seems the asteroids simply came too much earlier. If it had been an event triggered by the asteroid, then the remains of the asteroid would be at the same level in the earth's surface as the dinosaur bones. Alternate theories are great, but they have to fit the data. That's a fundamental constraint. RTFA.
  • Rick Dickson
    They can't be sure of the dates between the extinction event and the KT impact. It's pure speculation. However, using deductive reasoning, I would venture that the asteroid caused the volcanic eruptions, and both events finished the dinosaurs. The earth is a closed geospheric system. All that pressure and force from the asteroid could have forced up magma near the surface in massive eruptions like the Deccan Traps. The Deccan Traps are not volcanoes, the magma came pouring out in huge quantities from fissures in the weak crust. I believe this to be the case based on other circumstantial evidence involving the Siberian Trap eruptions (also not volcanoes) right after the PT (Permian Triassic) impact event about 250 million years ago off the coast of Australia. Again it's simple physics: pressure and force exerted on a sphere at a given point with a crust and partially semi-liquid interior will cause that liquid to erupt at weak points in the crust. You can prove this theory by firing a BB gun at a rotten tomato. Tomato juice will erupt from fractures in the rotten skin elsewhere than at the BB entry point.
blog comments powered by Disqus