Massive Volcanic Eruptions Accompanied Dinosaur Extinction 78
schwit1 writes: A careful updating of the geological timeline has shown that massive volcanic eruptions aligned with the extinction event that wiped out the non-avian dinosaurs 66 million years ago (abstract). "A primeval volcanic range in western India known as the Deccan Traps, which were once three times larger than France, began its main phase of eruptions roughly 250,000 years before the Cretaceous-Paleogene, or K-Pg, extinction event, the researchers report in the journal Science. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava. The main phase of eruptions comprised about 80-90 percent of the total volume of the Deccan Traps' lava flow and followed a substantially weaker first phase that began about 1 million years earlier.
The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event."
The results support the idea that the Deccan Traps played a role in the K-Pg extinction, and challenge the dominant theory that a meteorite impact near present-day Chicxulub, Mexico, was the sole cause of the extinction. The researchers suggest that the Deccan Traps eruptions and the Chicxulub impact need to be considered together when studying and modeling the K-Pg extinction event."
Antipodal eruptions (Score:5, Interesting)
This may revive the theory [nytimes.com] that the Deccan traps were formed at the antipode of a major eruption - the seismic waves will focus there, and could crack the Earth's crust (for a really big impact).
It seems logical, and the positions more or less fit, but the question was always whether the timing was viable.
Now, where is the crater that formed the Siberian traps [wikipedia.org]. And, did it end the Permian period?
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I'd be more inclined to believe we don't have our dating methods perfected quite yet.
Wait: you talking about archaeologists or slashdot members here?
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Either you are a creationist who believes humans and non-Avian dinosaurs coexisted or don't know the difference between an archaeologist and a paleontologist. We are talking about events that occurred about 65 MY ago, long before humans.
Re:Antipodal eruptions (Score:5, Funny)
I'd be more inclined to believe we don't have our dating methods perfected quite yet.
Wait: you talking about archaeologists or slashdot members here?
Either you are a creationist who believes humans and non-Avian dinosaurs coexisted or don't know the difference between an archaeologist and a paleontologist.
No, see, he was making a joke. "Dating" is a homonym, it can mean the act of establishing how old a thing is or it can mean the act of romantic courtship. And he's making a joke about how people on Slashdot might not be good at interacting with (typical) females since they tend to be so literal and have a hard time doing things like interpreting social meaning or context or...
You know what? Fuck it, you're right. He's a creationist.
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I turn it off before I come onto Slashdot, since this is meant to be a news site, not a comedy forum.
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If that were true, one wouldn't expect such a close match between geochronology of different element to element transitions. Both U-Pb and Ar dating techniques for the K-T boundary are within less than 100,000 K-T of one another.
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meant to say "within less than 100,00 k yr of one another.
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Our dating methods are not by any means perfect. The best dating so far puts the start of the Deccan around 200,000 years before the Chicxulub impact, +/- 65,000 years. That's about 3-sigma, or significant at around the 1% level. There is about a 1% chance that the null hypothesis (the Deccan and Chicxulub events were contemporaneous, or the the Deccan occurred after the Chicxulub impact) is true and that this dating result
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The researchers are NOT implying support for the "antipodal eruption model". the sequence of events is wrong for that theory to be true, without the existence of backwards-in-time time travel.
The scenario they are suggesting (which Keller has been banging on for a couple of
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Now, where is the crater that formed the Siberian traps. And, did it end the Permian period?
Well, looking at a couple maps on Google of the continent positions during the Permian Period, It would seem someplace in or around Antarctica was Siberia's anitpode. So, the crater would be under a lot of cold water or a lot of ice.
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Cool, thanks for the reference. (A paper from the time of the modern dinosaurs, when the AGU still had a Spring Meeting in Baltimore.)
It looks like it is even in the right place (see above).
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and about as convincing as "evidence of life on the moon" because there is a rock with what looks like a face on it.
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From the link:
The crater is about 300 miles wide. It was found by looking at differences in density that show up in gravity measurements taken with NASA's GRACE satellites. Researchers spotted a mass concentration, which they call a mascon-dense stuff that welled up from the mantle, likely in an impact.
So Frese and colleagues overlaid data from airborne radar images that showed a 300-mile wide sub-surface, circular ridge. The mascon fit neatly inside the circle.
Far from definite but the evidence is far stronger than you are making out.
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However, the hypothesis that a major astrobleme is necessary to trigger a Large Igneous Province at the impact's
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Gee, I can't even blame autocorrect :
that the Deccan traps were formed at the antipode of a major impact
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Except, the theory is trivially disproved - during the Cretaceous period [wikipedia.org], the Chicxulub crater and the Deccan traps weren't at each others antipodes.
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Uh, if you look at the correct map [cpgeosystems.com] and note that the Deccan traps were on the triangular Indian plate sailing around in the middle of the ocean, you'll note that the alignment is actually reasonably good.
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Only if you think that being off by about 10,000 km is "reasonably good". What kills the "killer" asteroid hypothesis is that the bulk of the biogeostratigraphic and high-resolution geochronological evidence now both suggest that the bolide impact predates the mass-extinction by about 100-150 kyrs.
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Only if you think that being off by about 10,000 km is "reasonably good". What kills the "killer" asteroid hypothesis is that the bulk of the biogeostratigraphic and high-resolution geochronological evidence now both suggest that the bolide impact predates the mass-extinction by about 100-150 kyrs.
The circumfrence of the earth is ~40,000km, being 10,000km off implies being a quater of the world away. I can't see that looking at the map provided by mbone. The map divides the earth into 12 longitude sections with the rough location of the impact crater and the Indian land mass being seperated by 6 longitude sections. Similarly the impact site and the location of the Indian land mass are roughly symmetric about the equator.
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As part of that process, extension of the area before separation led to the tilting of substantial fault blocks as well as the transport of mudrocks to considerable depths and temperatures, where they cooked to produce hydrocarbons (oil and gas) which then migrated upwards into traps formed in the tilted fault blocks.
Which might just possibly give a hint as to why the are
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I've never found the antipodal argument convincing. Seismic waves converge at the antipode of an impact only if the target is spherically symmetric and isotropic. In the actual Earth, you have reflections off all kinds of laterally varying boundaries. Also, the sound speed differs substantially between continental and oceanic crust, so the path matters quite a bit.
The Chixulub impact is also not that big (as planetary-scale impacts go). The projectile was what, 10 km? Shock heating is only significant withi
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I've never found the antipodal argument convincing. Seismic waves converge at the antipode of an impact only if the target is spherically symmetric and isotropic. In the actual Earth, you have reflections off all kinds of laterally varying boundaries. Also, the sound speed differs substantially between continental and oceanic crust, so the path matters quite a bit. The Chixulub impact is also not that big (as planetary-scale impacts go). The projectile was what, 10 km? Shock heating is only significant within a few times the projectile diameter.
I'm not a geophysicist but I do write software for the field so so I do have some limited knowledge of it. With the disclaimer out of the way, forgive me if I am wrong but:
1. Would anistropy mater much in this situation? I know it matters a lot in seismic tomography but the magnitude of the waves here is, well, of a completly different order of magnitude (excuse the pun). Would the physics creating angle dependent and/or horizontal velocity variations in the crust still hold up? Would they mater much on thi
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It has never been convincing energetically.
The improvements in dating over the last decade or so have killed it dead. It has shuffled off this mortal coil and gone to join the Choir Immortal etc etc. It is an ex-hypothesis.
While the hypothesis laid out before us may never have been called "beautiful", it was at least a respectable. And here it is - laid low not by one ugly fact, but a swarm of fact-flechettes tearing it to shreds. Alas, poor Yorick-the-an
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No it won't because he data provided by Keller and colleagues in another paper clearly demonstrate using biostatigraphy and high resolution geochronology that the impact event took place between 100-150 ky BEFORE the KT mass-die off that defines the K-T boundary. They show that cosmic spherules from the impact are, because of bioturbation, widely distributed in a much wider time horizon than proponents of of the asteroid extinction theory have assumed, including the famous Rio Brazos deposits. They conclu
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The last time I read one of Keller's papers while the ink was still damp, she was pushing for around 60~75 kyr between Chicxulub and K-Pg, with around 200kyr between the start of the Deccan and Chicxulub. Which is a real triumph of differential geochronology on a global scale - error bars of around 0.1% of value for two events which are reasonabl
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More like all the dinosaurs decided to commit suicide, so they all jumped into volcanoes at the same time, plugging them up with their bodies. Finally, the pressure got too high and kablam! Massive volcanic eruptions around the Earth.
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Neglecting your typo of "eruption" for "impact", no ; this kills it as dead as a very dead thing(*).
Gerta Keller (the Princeton-based re
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Do you have a thought-through reason for assuming that no major series of eruptions, centred on a small area in space and time, can occur without a preceding antipodal major impact?
Please note my comment above : the start of the Deccan Traps happened several hundred thousand years before the Chicxulub impact. If you're really, really serious about asserting that the Chicxulub impact caused the Deccan
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no, it was Baldrick's underpants.
Does this mean (Score:2)
That we don't have to worry about asteroids any more?
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Well, it is thought we've found all the dinosaur-killer-size asteroids, and that none are going to impact Earth soon. But there are still plenty of smaller ones that could take out a major city if they hit in the wrong spot. The shock wave from the Chelyabinsk meteor [wikipedia.org] caused injuries, though mainly from broken glass. Plus, you never know where a comet's going to appear.
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That's sort-of true for asteroids. Astronomers think that they've found around 90% of the expected population of Earth-crossing multi-kilometre Main Belt asteroids. But if the models are wrong, or we're looking at a non-Main Belt asteroid ... then that 90% figure doesn't hold. (And 90% found still leaves 10% un-found.)
However, an impactor coming in on a cometary (Kuiper Belt or Oort Cloud aphelion) orbit is another matter. Considerably
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We still have to worry about astroblemes. A repeat of (for an example) the Chicxulub impact would certainly devastate the Western hemisphere. Think of tsunami washing [I forget the name - range of hills along the north edge of Texas. Ozarks?] as kilos of red hot debris falls on every 10 sq.m of the hemisphere, with the subsequent conflagration.
It might not be a species-ending event for Homo sapiens, but that would be due to our wide geographic range and the presence of locally abundant stores of both f
Things happen - multiple things (Score:5, Informative)
I'm not convinced many actual scientists believe that the Chicxulub asteroid impact "was the sole cause of the extinction" - the best version I've heard is that the Deccan Traps eruptions had already put the ecosystem under stress.
The degree to which each event contributed to the mass extinction remains a fascinating question.
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Back in the early 90s I had the opportunity of participating on a paleontological expedition to the badlands of Montana. The soil was built up over hundreds of millions of years and flooding cut through the soft soil leaving a stratigraphy that is dramatic and easy to read. You can even see the Chicxulub ejecta, a chocolate brown horizontal line about the width of your hand.
Now whole dinosaur skeletons are a rare find. You can spend a whole season tramping through the badlands and never find two bones t
So - an impact of an asteroid.... (Score:2)
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The show that I watched had the theory that the extension event may have been a 'worst of two storms'
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Thanks to the work of Keller and others, we now know that that least some and possible a very large component of the Deccan vulcanism predated the bolide as did significant amounts of change in species composition.
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(1) T0 : Deccan Traps start erupting (along with the Reunion volcanics, probably, from the palaeogeography)
(2) +170,000 years : Chicxulub impact.
(3) + short period, maybe up to ~60,000 years : Dinosaurs and many other groups start going extinct.
Although, given the imprecision of the timing for large, long-lived animals compared to short-live
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The only problem with that is that some volcanic activity predated the bolide impact.
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No, they're not. They're saying that some of the main effects which have previously been attributed to this impact actually occurred before the impact. Therefore the main effects are not things that were caused by the impact. Minor things (huge earthquakes ; mega tsunami ; hundred-metre thick rains of red-hot glass spherules) were limited to the Caribbean basin and surrounding areas (up to Ca
Probably a mix (Score:3, Interesting)
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well scientists care about these things because the more knowledge we have of the past the better we can predict the future. scentists on the other hand, only care about the stench of your butt.
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We'll be very interested if they come back.
Then we'll be interested in how they taste.
Statistically not drastic (Score:4, Interesting)
The summary states that over 750,000 years the volcanoes emitted 1.1 E 6 km^2. Over that timespan it doesn't seem like much, a bit more than 1 km^2 a year. This does not seem that significant.
For instance, the Bardarbung volcano in Iceland, which erupted this year, has already produced 1 km^2 of lava, and has no sign of stopping. At that rate, for 750,000 years it would be close to the magnitude of the volcanoes in the summary. And yet the impact of Bardarbung on earthly climate is close to negligible - we are not yet extinct in any case. For an extinction event one would expect something a bit more drastic, it would seem to me.
Some info on Bardarbung here [volcanodiscovery.com]
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That should be km^3 of course, silly.
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1 km^3 a year isn't that drastic as a major event, nor is the current eruption in Bardarbunga.. Laki (another Icelandic volcano) erupted in 1783. The eruption lasted 8 months and produced 14 km^3 of basalt. However it is important to remember that the amount of lava is a poor scale because the major impact on wildlife and plants comes from gasses. However lava can be gas rich and gas poor meaning just measuring lava gives a large margin for error on environmental impact. However the amount of lava is still
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Thanks for the information. Volcanoes are amazing things. I remember when Mt. St. Helens erupted. It caused enormous damage and yet not too many things are extinct because of it. To have so many extinctions linked to one timespan seems to indicate something much more than just a series of volcanoes. Of course any life suffering from a cataclysmic event would not be helped by a long series of eruptions.
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On a human scale, yes.
Human scale isn't the appropriate unit of measure. This is a volcanic event ; as volcanoes go, Mt St Helens wasn't much more than a fart and a squirt. It just happened to be a fart and a squirt that impinged on human-inhabited areas.
I'm trying to remember the numbers on Mt St Helens - not committed to memory as so unimportant an event - but it's about the scale of the current Bardarbunga event, plus or minus a factor of a couple? It wasn't a Pinatubo.
Watch RadioLab Live: Apocalyptical (Score:1)
Anyone interested in a plausible physics backed explanation as to how to kill all dinosaurs off the face of the planet should watch the youtube video Radiolab Live: Apocalyptical. A bonus is the Reggie Watts performances - as he's improvisational there's two extra videos, the November 22 one shouldn't be missed for yet another fun dinosaur theory.
The above solution explains why no islands of dinosaurs could of survived past the K-Pg event. That there were some big volcanos giving a few local areas a hard ti