Dinosaur Deaths Outsourced to India?

Oct 29, 2007
Dinosaur Deaths Outsourced to India?
A vertical mile of Deccan lavas visible from Arthur's Seat at Mahabaleshwar. Photo courtesy Mike Widdowson

A series of monumental volcanic eruptions in India may have killed the dinosaurs 65 million years ago, not a meteor impact in the Gulf of Mexico. The eruptions, which created the gigantic Deccan Traps lava beds of India, are now the prime suspect in the most famous and persistent paleontological murder mystery, say scientists who have conducted a slew of new investigations honing down eruption timing.

"It's the first time we can directly link the main phase of the Deccan Traps to the mass extinction," said Princeton University paleontologist Gerta Keller. The main phase of the Deccan eruptions spewed 80 percent of the lava which spread out for hundreds of miles.

It is calculated to have released ten times more climate altering gases into the atmosphere than the nearly concurrent Chicxulub meteor impact, according to volcanologist Vincent Courtillot from the Physique du Globe de Paris.

Keller's crucial link between the eruption and the mass extinction comes in the form of microscopic marine fossils that are known to have evolved immediately after the mysterious mass extinction event. The same telltale fossilized planktonic foraminifera were found at Rajahmundry near the Bay of Bengal, about 1000 kilometers from the center of the Deccan Traps near Mumbai. At Rajahmundry there are two lava "traps" containing four layers of lava each. Between the traps are about nine meters of marine sediments. Those sediments just above the lower trap, which was the mammoth main phase, contain the incriminating microfossils.

Keller and her collaborator Thierry Adatte from the University of Neuchatel, Switzerland, are scheduled to present the new findings on Tuesday, 30 October, at the annual meeting of the Geological Society of America in Denver. They will also display a poster on the matter at the meeting on Wednesday, 31 October.

Previous work had first narrowed the Deccan eruption timing to within 800,000 years of the extinction event using paleomagnetic signatures of Earth's changing magnetic field frozen in minerals that crystallized from the cooling lava. Then radiometric dating of argon and potassium isotopes in minerals narrowed the age to within 300,000 years of the 65-million-year-old Cretaceous-Tertiary (a.k.a. Cretaceous-Paleogene) boundary, sometimes called the K-T boundary.

The microfossils are far more specific, however, because they demonstrate directly that the biggest phase of the eruption ended right when the aftermath of the mass extinction event began. That sort of clear-cut timing has been a lot tougher to pin down with Chicxulub-related sediments, which predate the mass extinction.

"Our results are consistent and mutually supportive with a number of new studies, including Chenet, Courtillot and others (in press) and Jay and Widdowson (in press), that reveal a very short time for the main Deccan eruptions at or near the K-T boundary and the massive carbon dioxide and sulfur dioxide output of each major eruption that dwarfs the output of Chicxulub," explained Keller. "Our K-T age control combined with these results strongly points to Deccan volcanism as the likely leading contender in the K-T mass extinction." Keller's study was funded by the National Science Foundation.

The Deccan Traps also provide an answer to a question on which Chicxulub was silent: Why did it take about 300,000 years for marine species to recover from the extinction event? The solution is in the upper, later Deccan Traps eruptions.

"It's been an enigma," Keller said. "The very last one was Early Danian, 280,000 years after the mass extinction, which coincides with the delayed recovery."

Keller and her colleagues are planning to explore the onset of the main phase of Deccan volcanism, that is, the rocks directly beneath the main phase lavas at Rajahmundry. That will require drilling into the Rajahmundry Traps, a project now slated for December-January 2007/2008.

Source: Geological Society of America

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SDMike
3.3 / 5 (3) Oct 29, 2007
Chicxulub CAUSED the Deccan Traps. Take a globe of the earth with the continents arranged as they were at the end of the Cretaceous. Draw a line from Chicxulub through the center of the earth. Extend this line and it exits the earth's surface at the Deddan Traps.

Unfortunately paleontologists like Gerta Keller just will not listen to non-paleontologists. Psychologists (like me) couldn't possibly draw a straight line or look up a K-T map.

However, volcanologists who I have spoken with about this idea rather like it.

What do you say Dr. Keller?
photojack
3.7 / 5 (3) Oct 29, 2007
SDMike, That's interesting, potentially a PhD. thesis! Definitely more research needs to be done. I would like to know how Gerta Keller would explain away the "shocked Quartz" and the Iridium at the KT boundary which are both indivcative of a meteor or comet impact and NOT a mass volcanic event. I think Dr. Alvarez put the puzzle pieces together correctly in the "Crater of Doom" scenario he invisioned. He corroborated it with very much compelling evidence and joint scientific research. If the timing was synonymous, maybe it was a "one, two punch" that, when combined, might be called the biggest "overkill" since the Permian extinction!
SDMike
4.5 / 5 (2) Oct 29, 2007
You've got it!

The one, two punch resolves all the issues. Well, there is an issue of how the forces are transmitted - surface waves, forces transmitted through the mantel, the interior, arrival time, compression then tension, etc. I wish I had a physical model I could shoot with an air gun or something!

If I was 60 years younger I might go for a Ph.D. in one of the earth sciences. But it needs more energy than I have left. I just whine.

Thanks for the comments!
fredrick
not rated yet Oct 30, 2007
"The one, two punch resolves all the issues. Well, there is an issue of how the forces are transmitted - surface waves, forces transmitted through the mantel, the interior, arrival time, compression then tension, etc."

Those aren't small issues; and I'm always sceptical when someone claims their hypothesis 'resolves all the issues' (just haven't been looking hard enough, even the best theories have issues). For example, does it explain why the dinosaurs died, but not the frogs?

its unlikely that these events happened at the same time, "nearly concurrent" means somewhere within a hundred thousand years to a couple million. In fact, this article reminded me of one of Keller's articles ealier this year:
http://geoweb.pri...r_et_al_ EPSL_2007.pdf

How would a meteor impact cause volcanism on the other side of the world which may have occured around the same time, or maybe a couple hundred thousand to a million years later? And what about other major meteor impacts, it would add a lot of weight to your hypothesis if you could find major volcanic eruptions on the opposite sides of the Earth for the following big impacts: http://en.wikiped...on_Earth
fredrick
not rated yet Oct 30, 2007
don't know why that link keeps breaking, try this one instead: http://www.pnas.o...396101v1
either that or search for "Chicxulub impact predates the K-T boundary mass extinction"
out7x
1 / 5 (1) Dec 01, 2007
I think it would take a 1,2,3 punch to cause the K-T extinction. The Permian extinction tells us life is very robust to survive.
BTW, shocked quartz can be created either way.
CactusCritter
not rated yet Dec 22, 2007
The greatest extinction event, which occurred at the Permian-Triassic boundary, has been suggested as caused by the magma extrusion and gaseous emmissions associated with the formation of the Siberian Traps which I believe put out much more magma than the Indian Traps event.

Can anyone confirm or deny that? The book which treats the matter of the Sibrian Traps, 'When Life Nearly Died", is on loan to one of my children.
MikeyK
not rated yet Dec 22, 2007
This is a fascinating story, I hope you don't mind if I add my own penny's worth! Back in 2001 comet-originated 'Buckyballs' were found in Permian/Triassic deposits around the world and a possible impact site found near Antartica, which would have been at the antipode of Siberia at that time. Another point of interest, on Mercury there is a huge crater with very unusual features at the exact antipode suggesting a convergence of shockwaves hitting the point. I know Mercury is very different from Earth but it shows that there is at least a possibility of antipode effects from a large impact. It certainly warrants further study.
MarkG
not rated yet Dec 22, 2007
Several features antipodal to impacts appear on Mercury, Mars, the Moon, Callisto, and Earth.

I've always felt the impact begot the eruptions.
rgwisk
not rated yet Dec 30, 2007
I am so happy to see this discussion. I was just watching the history of the planet on the history channel where they stated the eruptions in India and the meteor in Mexico. I immediately had the thought comparing when one hits their head, how a hematoma can occur on the opposite side...just makes sense that the meteor's force caused the eruptions in India. (sorry, I'm a newbie, just had to get it out)