Asteroid impact, volcanism were one-two punch for dinosaurs

Asteroid impact, volcanism were one-two punch for dinosaurs
Layered lava flows of the Deccan Traps east of Mumbai, India. Credit: Mark Richards/UC Berkeley

Berkeley geologists have uncovered compelling evidence that an asteroid impact on Earth 66 million years ago accelerated the eruptions of volcanoes in India for hundreds of thousands of years, and that together these planet-wide catastrophes caused the extinction of many land and marine animals, including the dinosaurs.

For 35 years, paleontologists and geologists have debated the role these two global events played in the last mass extinction, with one side claiming the were irrelevant, and the other side claiming the was a blip in a long-term die-off.

The new evidence includes the most accurate dates yet for the volcanic eruptions before and after the impact. The new dates show that the Deccan Traps , which at the time were erupting at a slower pace, doubled in output within 50,000 years of the asteroid or comet impact that is thought to have initiated the last mass extinction on Earth.

Both the impact and the volcanism would have blanketed the planet with dust and noxious fumes, drastically changing the climate and sending many species to an early grave.

"Based on our dating of the lavas, we can be pretty certain that the volcanism and the impact occurred within 50,000 years of the extinction, so it becomes somewhat artificial to distinguish between them as killing mechanisms: both phenomena were clearly at work at the same time," said lead researcher Paul Renne, a UC Berkeley professor-in-residence of earth and planetary science and director of the Berkeley Geochronology Center. "It is going to be basically impossible to ascribe actual atmospheric effects to one or the other. They both happened at the same time."

The geologists argue that the impact abruptly changed the volcanoes' plumbing system, which produced major changes in the chemistry and frequency of the eruptions. After this change, long-term volcanic eruptions likely delayed recovery of life for 500,000 years after the KT boundary, the term for the end of the Cretaceous and the beginning of the Tertiary period when large land animals and many small sea creatures disappeared from the fossil record.

"The biodiversity and chemical signature of the ocean took about half a million years to really recover after the KT boundary, which is about how long the accelerated volcanism lasted," Renne said. "We are proposing that the volcanism unleashed and accelerated right at the KT boundary suppressed the recovery until the volcanoes waned."

Co-author Mark Richards, a UC Berkeley professor of earth and planetary science and the one who originally proposed that the comet or reignited the Deccan Traps lava flows, is agnostic about which event was the real death knell for much of life on Earth. But the link between the impact and the flood basalts is becoming harder to deny.

Asteroid impact, volcanism were one-two punch for dinosaurs
A map showing the extent of the Deccan Traps volcanic region in India, which dates from 64-67 million years ago. The rectangle shows the region near Mumbai from which the Berkeley team obtained lava samples used in the new precision dating of the eruptions around the time of the asteroid or comet impact 66 million years ago. Credit: Paul Renne, Berkeley Geochronology Center & UC Berkeley

"If our high-precision dates continue to pin these three events - the impact, the extinction and the major pulse of volcanism - closer and closer together, people are going to have to accept the likelihood of a connection among them. The scenario we are suggesting - that the impact triggered the volcanism - does in fact reconcile what had previously appeared to be an unimaginable coincidence," he said.

Renne, Richards and their colleagues will publish the new dates for the Deccan Traps eruptions in the Oct. 2 issue of the journal Science.

Impact or volcanism?

Since 1980, when UC Berkeley geologist Walter Alvarez and his father, the late UC Berkeley physicist Luis Alvarez, discovered evidence of a comet or asteroid impact on Earth 66 million years ago, scientists have argued about whether the impact was the cause of the that occurred at the same time, the end of the Cretaceous period, or the KT boundary. Some argued that the huge volcanic eruptions in India known as the Deccan Traps, which occurred around the same time, were the main culprit in the extinctions. Others insisted the death knell had been the impact, which left behind a large crater dubbed Chicxulub off Mexico's Yucatan peninsula, and viewed the Deccan Traps eruptions as a minor sideshow.

Earlier this year, Richards, Renne and eight other geoscientists proposed a new scenario: that the impact ignited volcanoes around the globe, most catastrophically in India, and that the two events combined to cause the KT extinction.

Asteroid impact, volcanism were one-two punch for dinosaurs
Paul Renne inspects a reddened soil horizon between lava flows in the Deccan Traps region of India. Renne is director of the Berkeley Geochronology Center and a professor-in-residence at UC Berkeley. Credit: Mark Richards/UC Berkeley

In attempts to test this hypothesis, the team last year collected lava samples from throughout the Deccan Traps east of Mumbai, sampling flows from near the beginning, several hundred thousand years before the extinction and near the end, some half a million years after the extinction. High-precision argon-40/argon-39 isotope dating allowed them to establish the chronology of the flows and the rate of flow over time.

In the Science paper, they describe major changes in the Deccan Traps volcanism, which was probably "bubbling along happily, continuously and relatively slowly" before the extinction, Renne said. After the impact, the eruption rate more than doubled and the volcanism became more punctuated, with more voluminous lava flows interspersed with long periods of quiet. This is consistent with a change in the underground plumbing feeding the flows, he said: Smaller magma chambers before the impact became larger, which means they took longer to fill but spewed more lava when they did erupt.

"At the KT boundary, we see major changes in the volcanic system of the Deccan Traps, in terms of the rate at which eruptions were happening, the size of the eruptions, the volume of the eruptions and some aspects of the chemistry of the eruptions, which speaks to the actual processes by which the magmas were generated," Renne said. "All these things changed in a fundamental way, and increasingly it seems they happened right at the KT boundary. Our data don't conclusively prove that the impact caused these changes, but the connection looks increasingly clear."

Richards said that a large nearby earthquake of a magnitude 8, 9 or 10 - as large or larger than the quake that struck Japan in 2011 - could also have reignited the Deccan Trap flows. In fact, large quakes may have rattled underground magma chambers and ignited eruptions throughout Earth's history. But the simultaneous changes in the lava flows and the impact at the KT boundary seem more than mere coincidence.

"These changes are consistent with an accelerated rate of magma production and eruption that you could get from a large earthquake such as would be created by the Chicxulub impact," he said.

In 2013, Renne and his team at the Berkeley Geochronology Center and elsewhere also dated the KT boundary extinction and dust from the impact and found they occurred within less than 32,000 years of one another - the blink of an eye in geologic terms, he said. Renne's team plans to obtain isotope dates for more basalt samples from the Deccan Traps to detail the history of the lava flows that cover much of western India, in order to better understand how they changed with time and correlate to the impact and extinctions. Meanwhile, Richards is working with volcano experts to understand how large ground shaking caused by earthquakes or asteroid impacts affects .


Explore further

Did dinosaur-killing asteroid trigger largest lava flows on Earth?

More information: State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact, www.sciencemag.org/lookup/doi/ … 1126/science.aac7549
Journal information: Science

Citation: Asteroid impact, volcanism were one-two punch for dinosaurs (2015, October 1) retrieved 18 September 2019 from https://phys.org/news/2015-10-asteroid-impact-volcanism-one-two-dinosaurs.html
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Oct 01, 2015
This definitely feels like a converging solution to the question recently.

Oct 01, 2015
Scientifically, all the evidence used to show that large impacts were the cause of craters could be used to show that it was large electrical discharges that were the cause. Of course mainstream 'science' will never even look at the possibility. And large electrical events would throw the whole time-line by radiometric dating of these events right out the window.

Oct 01, 2015
Some people have been saying this for decades.

Given continental "drift" and such, antipodal evidence suggests that both Deccan and Siberian Traps were the result of significant mass impactors.

Oct 01, 2015
There's a difference between saying something for decades and demonstrating robust empirical evidence for it. We can point out over and over and over and over that that's the difference between science and tinfoil armchair discussions, but it just never seems to sink in.

These Tesla worshipers are the worst. Though I had a very nice dream the other night that I took over one of their conventions, hooked them into a series circuit and sent one amp through their testicles at random intervals for hours and hours and hours. Would certainly be more useful for humanity than any of their inane theories.

Oct 01, 2015
Most the stoopid 'lectricity herd are Zionists. They all base their ideas on supposed magical properties of the Arc of the Covenant. Some are quislings, but many are expressly trying to implement the Jew World Order.


@jimpieceofshit

I'll be 69 in another month but in the highly improbable chance we would meet in a bar you would be crying for mercy.

Oct 01, 2015
Back on topic...

Could this be the ultimate extant example of mega-fracking ??

Oct 01, 2015
The problem for me is that their is so much that just doesnt fit either of the two theories. I can understand massively large reptiles suffering from lack of heat but it doesnt explain what happened to the sea life. In addition why would a early ancestor of the crocodile or iguana survive but not a velociraptor? Why would no small dinosaurs survive? Why would killer whales survive but not a megladon? None of it really makes any sense and my personal theory is that either bacteria or viruses had something to do with extinctions as well.

Oct 02, 2015
The massive eruptions of the Deccan traps released an enormous amount of CO2. The resulting rapid warming and ocean acidification is what killed the dinosaurs and ocean life (http://www.skepti...urs.html - also see the similar situation with the Siberian traps and the end Permian extinction). As for why the iguana and crocodile survived, probably their niches helped them where it didn't help the velociraptor. Crocodiles live on land and in water, which surely helped their ancestors. Who said no small dinosaurs survived (chirp chirp)? Since killer whales didn't exist before the KT extinctions, it seems a little silly to claim they survived. As far as I know, the only mammals around at the time were very small.

Frankly, it all makes a great deal of sense and you'll need to come up with a lot of evidence against this if you want to try to dispute it.

Oct 02, 2015
Jayded, small dinosaurs did survive. Look out your window and you Will probably see some of their descendants flying by. Some Small avian dinosaurs made it.

megladon went extinct much later than the KT event, most likely because the primitive whales it relied on went extinct. Killer whales are not a good comparison. Why didn't killer whales ancestors go extinct too? They adapted to changing environments better.


Oct 02, 2015
Seems like the earth's crust rang like a bell, and weak structures where the surface was almost liquid (magma chambers) had a tsunami action. Acidification of the oceans by CO2 would have killed off large amounts of sea life, (plankton, krill, fish) causing larger predators to starve. Same thing on land. The survivors were the small animals that could eke out a living on a very limited food supply. Crocks, birds, small lizards, small mammals, etc., were the survivors. When the smoke cleared, vegetation returned in force, and then larger herbivores. Predators increased in size accordingly.

Oct 02, 2015
could be used to show that it was large electrical discharges that were the cause
@solon
actually, no, it can't. there is a known set of physical properties that would be evident as well as traceable if there were electrical impacts in a region, from fulgerites to other known properties in the ground, etc
see: https://en.wikipe...ulgurite

perhaps you should consider taking some basic courses to learn about the physics behind electrical and physics related science?
try this link: http://ocw.mit.ed...=physics


Oct 03, 2015
Many species have disappeared due to human activity and this process continues today. So there is a red book which describes the endangered animal and plant species due to violation of bio balance in their natural habitat. On this occasion I do not remember in the recent past to has fallen big asteroid to the Earth, so the explanation in the article sounds no very scientific.

Oct 04, 2015
So all the species we find as fossills today were all killed off by man and his activities?
Im surprised youd try to take that approach to claim the article is "unscientific". I thought fossil beds were from the flood....
If you believe the earth is about 6000 years old its definitely been hit many times in the last 6000 years. Look up large impact craters once.

Oct 04, 2015
The fossil can form only if the earth mass very quickly bury the organism and interrupt it access to air and predators. The global flood is perfect for this purpose.
So where is your big craters from meteorites? On the picture I can not see such thing.
Only read about the interpretation of the author of the article. You again demonstrate your wishful thinking which in fact is very useless approach.

Oct 05, 2015
The fossil can form only if the earth mass very quickly bury the organism and interrupt it access to air and predators. The global flood is perfect for this purpose.

OK. How does your comment of man driving species extinct in the past and present without an asteroid being needed so its unscientific to consider it for previous mass extinctions that are known from fossil records that you say were created in the flood make sense? Was it us or your vain vengeful tyrant sociopath egotistical insecure god responsible?
Do you concede your man driving species extinct now so its likely we and not an asteroid behind the mass extinction and fossils was a bunch of contradictory to your beliefs nonsense?

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