Massive Volcanic Eruptions Accompanied Dinosaur Extinction

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Massive Volcanic Eruptions Accompanied Dinosaur Extinction

Posted by Soulskill on Saturday December 20, 2014 @03:35AM from the some-say-dinosaurs-can't-swim-in-magma dept.

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."

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Antipodal eruptions by mbone · 2014-12-20 03:41 · Score: 5, Interesting

This may revive the theory 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. And, did it end the Permian period?
1. Re:Antipodal eruptions by The+Real+Dr+John · 2014-12-20 03:53 · Score: 1
  
  The Deccan traps have long been suspect, and the antipodal theory has been around for some time too. From the article: "The researchers suggest that the Deccan Traps eruptions and the meteorite impact near present-day Chicxulub, Mexico, need to be considered together when studying and modeling the Cretaceous-Paleogene extinction event."
  
  --
  A brain is a terrible thing to waste... Mind? That's debatable.
2. Re:Antipodal eruptions by olsmeister · 2014-12-20 03:57 · Score: 1
  
  It seems like the timing is so close that it is hard to believe it's a coincidence. I'd be more inclined to believe we don't have our dating methods perfected quite yet.
3. Re:Antipodal eruptions by killkillkill · 2014-12-20 04:02 · Score: 1
  
  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.
4. Re:Antipodal eruptions by killkillkill · 2014-12-20 04:23 · Score: 2
  
  Oh, maybe they found it already.
5. Re:Antipodal eruptions by Anonymous Coward · 2014-12-20 04:31 · Score: 0
  
  And some still will tell you that CO2 does not result in global warming.
  Anyway, since these events tends to span the massive extinction events, then it is quite likely that they either contributed or were the cause. Giant CO2 emitter + observed massive climate warming = extinction.
  Another thing is people do not realize that we live on a thin thin skin of the planet. It looks solid, but relatively that solid part is as thick as the surface tension layer on top of a lake. It looks solid to little bugs too. But then someone drops a rock and the bugs drown.
6. Re:Antipodal eruptions by mbone · 2014-12-20 04:41 · Score: 1
  
  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).
7. Re:Antipodal eruptions by mbone · 2014-12-20 04:44 · Score: 1
  
  Gee, I can't even blame autocorrect :
  that the Deccan traps were formed at the antipode of a major impact
8. Re:Antipodal eruptions by Anonymous Coward · 2014-12-20 05:17 · Score: 0
  
  True, but if we could use a model of the planet with cracks at the plates and all, and simulate tossing the mass of supposed asteroid at the planet, we could potentially calculate the amount of pressure build up inside the planet. assuming that the pressure is indeed great enough, we could even potentially calculate were that pressure might be released from and line up with the volcanic eruptions. I will keep in mind that the planet is quite big, and the Chicxulub impact is quite small in comparison, but would that be enough to build up pressure to make a series of volcanoes blow their top? I would love to research that.
9. Re:Antipodal eruptions by DerekLyons · 2014-12-20 05:30 · Score: 2
  
  Except, the theory is trivially disproved - during the Cretaceous period, the Chicxulub crater and the Deccan traps weren't at each others antipodes.
10. Re:Antipodal eruptions by mbone · 2014-12-20 05:36 · Score: 1
  
  Uh, if you look at the correct map 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.
11. Re:Antipodal eruptions by Convector · 2014-12-20 05:46 · Score: 2
  
  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.
12. Re:Antipodal eruptions by cellocgw · 2014-12-20 07:37 · Score: 2
  
  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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13. Re:Antipodal eruptions by Anonymous Coward · 2014-12-20 07:39 · Score: 0
  
  Not really, because one of the points of this paper was that the volcanism still began long before the mass extinction, and thus long before the timing of the Chicxulub impact. That hasn't changed. The new part is that even though it started earlier, the much of the volume of the volcanism is focussed at the boundary. I suppose you could speculate that being at the antipode might have enhanced the volcanism that was already occurring in the Deccan Traps area, but by that point the pathways for the magma were already well established to some degree.
14. Re:Antipodal eruptions by Anonymous Coward · 2014-12-20 07:47 · Score: 0
  
  FYI, you could read (and thereby place less blind credence in the impact theory):
  D. Archibald. Dinosaur Extinction and the End of an Era: What the Fossils Say. Columbia University Press. 1996.
  FWIW, this series by Columbia University Press is quite good, but not intended for the casual reader.
15. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:19 · Score: 1
  
  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 conclude that the biological impact of the bollide has been much exaggerated and changes in the morphology and presence of several microplankton species from both the area of the Decann traps and that mass-extinction was in any event, well underway at least locally in India and even at least for many sites in the Caribbean as well, BEFORE the "killer" bollide entered the Earth's atmosphere.
16. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:21 · Score: 1
  
  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.
17. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:23 · Score: 1
  
  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.
18. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:28 · Score: 1
  
  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.
19. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:33 · Score: 1
  
  meant to say "within less than 100,00 k yr of one another.
20. Re:Antipodal eruptions by turkeyfish · 2014-12-20 11:35 · Score: 1
  
  and about as convincing as "evidence of life on the moon" because there is a rock with what looks like a face on it.
21. Re:Antipodal eruptions by Jeeeb · 2014-12-20 13:03 · Score: 2
  
  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.
22. Re:Antipodal eruptions by Jeeeb · 2014-12-20 13:39 · Score: 1
  
  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.
23. Re:Antipodal eruptions by schnell · 2014-12-20 14:15 · Score: 4, 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.
  
  --
  "95% of all Slashdot .sig quotes are incorrect or completely fabricated." -Benjamin Franklin
24. Re:Antipodal eruptions by Jeeeb · 2014-12-20 14:34 · Score: 1
  
  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 this scale? Presumably the waves are spending most of the time traveling through the mantle.
  2. Similarly is being exactly spherically symmetric that important? Are the other stellar bodies were the antipodal phenomenon has been observed exactly spherically symmetric?
  http://www.newgeology.us/presentation35.html provides a reasonably good summary of the pro-antipodal argument. Even if the waves are not focusing on an exact point with equally timed first-arrivals you could still reasonably expect see something resembling antipodal effects.
25. Re:Antipodal eruptions by davester666 · 2014-12-20 15:58 · Score: 1
  
  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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26. Re:Antipodal eruptions by SourceFrog · 2014-12-21 01:48 · Score: 1
  
  Your humor-detection unit is bust
  
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  My other UID is three digits.
27. Re:Antipodal eruptions by RockDoctor · 2014-12-22 10:49 · Score: 1
  
  This may revive the theory 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).
  Neglecting your typo of "eruption" for "impact", no ; this kills it as dead as a very dead thing(*).
  
  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
  Gerta Keller (the Princeton-based researcher who has been banging this particular drum for a couple of decades now - to evident success) gets the Chicxulub impact at 60-80,000 before the K-Pg extinction event, iridium spike, base surges tsunamiites, etc, which would put the Deccan staring around 170,000 to 190,000 years before the K-Pg faunal changes. That is like suggesting that our actions today could be responsible for the demise of Homo erectus and the ascendancy of Homo sapiens.
  (*) As a geologist, I'm uncomfortable about describing something as "stone dead" : stones are full of life, with fascinating detailed histories. Not dead at all.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
28. Re:Antipodal eruptions by RockDoctor · 2014-12-22 10:57 · Score: 1
  
  I'd be more inclined to believe we don't have our dating methods perfected quite yet.
  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 is an error.
  This is not new news ; Keller has been pushing this for a couple of decades now, and as the dates have gradually been tightened (for both Chicxulub and for the start of the Deccan), the answer has become clearer : Deccan before Chicxulub. (Others have been pushing at the question for even longer than Keller, but she's been the most persistent doubter. And as such has performed a hugely valued task of forcing people to prove their statements - and they've been found wanting.
  In future decades, people will look back at this and put it in the text books with Wegener as a good example of an erroneous paradigm being pushed back against and defeated over a period of decades.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
29. Re:Antipodal eruptions by RockDoctor · 2014-12-22 11:04 · Score: 1
  
  Now, where is the crater that formed the Siberian traps [wikipedia.org]. And, did it end the Permian period?
  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 Traps, then you have a tremendous career ahead (and behind) you in the new physics of bidirectional time travel.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
30. Re:Antipodal eruptions by RockDoctor · 2014-12-22 11:11 · Score: 1
  
  My humour unit works fine.
  I turn it off before I come onto Slashdot, since this is meant to be a news site, not a comedy forum.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
31. Re:Antipodal eruptions by RockDoctor · 2014-12-22 11:17 · Score: 1
  
  From the article: "The researchers suggest that the Deccan Traps eruptions and the meteorite impact near present-day Chicxulub, Mexico, need to be considered together when studying and modeling the Cretaceous-Paleogene extinction event."
  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 decades) is that the environmental stresses due to the Deccan eruptions were damaging environments, stressing individuals and populations, damaging ecologies, and generally making life hard. Then there's a major impact at Chicxulub which makes a bad situation worse.
  [In true Slashdot style, I'll admit to not having RTFA - but unusually, it's because I have been watching the evidence for this build up over 20+ years. Contrary to what producers at Discovery channel (other poor quality popular science producers are available) express, there has never been unanimity over the Chicxulub-killed-the-dinosaurs theory within the industry.]
  [now I've RTFA - no surprises - it's exactly what I expected, having been following this debate for 20+ years.]
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
32. Re:Antipodal eruptions by RockDoctor · 2014-12-22 11:40 · Score: 1
  
  The Wilkes' Land structure is credible. However about 5 (10?) years ago another structure was proposed as the "Dimetrodon-killer" (Dimetrodon was a scary toothy land animal of the time. A "mammal-like reptile", IIRC.) The "Bedout" structure off NW Australia is about the right age A plagioclase separate from the Lagrange-1 exploration well has an Ar/Ar age of 250.1 Â± 4.5 million years.
  However, the hypothesis that a major astrobleme is necessary to trigger a Large Igneous Province at the impact's antipode does not have strong support. (Possibly it has no significant support - we have a very incomplete impact record.)
  The hypothesis (implicit, but never as far as I know proposed by a serious scientist) that a Large Igneous Province (LIP) is incapable of causing enough global environmental stress to cause a mass extinction is not proven. LIPs come in many sizes, and since they tend to bury their early phases under their later phases, it is very hard to measure their actual durations and eruption rates.
  The hypothesis that a large astrobleme is sufficient to cause a global mass extinction has not been proven. In fact, the classical case - the K-Pg or Chicxulub impact - itself shows an inconsistent story. Some dinosaurs died out (large ones) but small dinosaurs survived and are now the most species rich group of tetrapods (birds). Some free-floating plankton families died out (damn, where's a biostratigrapher when you need one?) and other, closely related families didn't. Some plant families died out, and others didn't.
  Contrary to what "popular science" programmes will tell you, the pattern of extinctions at the K-Pg extinction seems almost random. Which suggests that the Chixulub impactor was not, in itself, sufficient to take out all of a group of life forms.
  Possibly, to get a mass extinction, you need to combine a LIP (which is happening around 1/10th to 1/5th of the time) with another "point event" (impact [K-Pg], methane-clathrate destabilisation [Pg-Eo], ocean sulphate chemistry fuck-up [Palaeozoic-Mesozoic], or another impact [Manicouagan + 2 others in a chain, Triassic-Jurassic]). It isn't a simple story. But it's more likely to not be incorrect than the simple story.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
33. Re:Antipodal eruptions by The+Real+Dr+John · 2014-12-22 12:31 · Score: 1
  
  I've never been convinced by the Chicxulub-killed-the-dinosaurs theory, and have always preferred the more gradual theory that seems better in line with the evidence as you remind us. Many dinosaur lineages had been dying out in various locations for millions of years, and the climate was changing. There was a relatively short-lived finale, but that seems more in sync with the Deccan traps in terms of the timing, and began well before Chicxulub.
  
  --
  A brain is a terrible thing to waste... Mind? That's debatable.
34. Re:Antipodal eruptions by RockDoctor · 2014-12-22 20:39 · Score: 1
  
  Unfortunately, the process that formed the Deccan was the process that led to the separation of the Indian plate from the African plate.
  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 area has been the subject of intense scrutiny in the last few years. When I first worked there, there wasn't an offset well log for 500km in one direction and 2500km in the other direction ; now there are about 6 major drilling programmes working the play, churning out a couple of new wells a month.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
35. Re:Antipodal eruptions by RockDoctor · 2014-12-22 20:44 · Score: 1
  
  I've never found the antipodal argument convincing.
  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-antipodal-eruption hypothesis. I knew him, Horatio. Poor sod never stood a chance.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
36. Re:Antipodal eruptions by RockDoctor · 2014-12-22 21:24 · Score: 1
  
  biostatigraphy and high resolution geochronology [show] that the impact event took place between 100-150 ky BEFORE the KT mass-die off that defines the K-T boundary
  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 reasonably close to antipodal.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Does this mean by rossdee · 2014-12-20 03:48 · Score: 1

That we don't have to worry about asteroids any more?
1. Re:Does this mean by itzly · 2014-12-20 04:03 · Score: 1
  
  You never had to worry in the first place.
2. Re:Does this mean by Anonymous Coward · 2014-12-20 04:04 · Score: 0
  
  Shit, brah, what kind of Space Nutter are you? The Death Asteroid is the only thing we as a Species must worry about!
3. Re:Does this mean by killkillkill · 2014-12-20 04:07 · Score: 1
  
  No, if it was an antipodal eruption, we have to worry more.
4. Re:Does this mean by Ken_g6 · 2014-12-20 05:44 · Score: 1
  
  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 caused injuries, though mainly from broken glass. Plus, you never know where a comet's going to appear.
  
  --
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5. Re:Does this mean by RockDoctor · 2014-12-22 20:20 · Score: 1
  
  No.
  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 food and information. It might well be a civilisation ending event, or at least put us back to around the Renaissance. Fairly big deal.
  If it had happened a mere 14 kyr ago, it could have extinguished pretty much the whole of the human race. Or at least, if it took out the appropriate area, wiped out agriculture for a few millennia. (14kyr BP is the approximate date of the Barringer crater.)
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
6. Re:Does this mean by RockDoctor · 2014-12-22 21:40 · Score: 1
  
  Well, it is thought we've found all the dinosaur-killer-size asteroids,
  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 higher impact velocities and therefore energy ; considerably shorter warning times - down to a few weeks, easily if you remember Hyakutake ; no good idea of a mass distribution. It's an open book.
  While we're living in one ecosystem, we're vulnerable at the species or kingdom level. It'd take a lot to eradicate the single-celled organisms, but plants and animals are much more vulnerable.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Re:So it wasn't global warming? by ihtoit · 2014-12-20 03:50 · Score: 2

no, it was Baldrick's underpants.

--
Political debates have me rolling my eyes so much I think I got optical whiplash. I should sue. - Foamy The Squirrel
Things happen - multiple things by Livius · 2014-12-20 03:55 · Score: 4, 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.
1. Re:Things happen - multiple things by hey! · 2014-12-20 09:08 · Score: 2
  
  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 that go together. But individual bones are more common, and bone fragments are more common still, and experts can often identify the group of dinosaurs or even the species of dinosaur a bone fragment came from, often a surprisingly small fragment of bone.
  What we were doing was assembling a database of species found by layer, which in turn maps to era. What the PI was finding was a shift towards species with anatomical adaptations to deal with heat. His opinion was that there was already a climate driven adaptive stress on the dinosaur population, which turned the aftermath of the Chicxulub impact into a knock-out blow.
  So the idea that there was more going on than an asteroid impact is hardly new. People were thinking that way twenty years ago.
  
  --
  Post may contain irony: discontinue use if experiencing mood swings, nausea or elevated blood pressure.
So - an impact of an asteroid.... by Bomarc · 2014-12-20 04:00 · Score: 1

I've heard this theory before & is not new news. The asteroid that struck (the Yucatan Peninsula) ~ 65 million years ago - was the size of Mt. Everest. The are proposing that this strike didn't have any secondary effects - such as volcanoes, earthquakes and the like? IMO ... such a LARGE impact would have ramifications for MANY years to come.
1. Re:So - an impact of an asteroid.... by Attila+Dimedici · 2014-12-20 04:25 · Score: 1
  
  That was my thought as well...did the eruptions pre-date the asteroid impact? If not, then it is reasonable to believe that the asteroid impact triggered the massive eruptions.
  
  --
  The truth is that all men having power ought to be mistrusted. James Madison
2. Re:So - an impact of an asteroid.... by Bomarc · 2014-12-20 04:42 · Score: 1
  
  Continuing the idea even more: Is it possible that the western India eruptions could have been caused by another asteroid? The size of the eruptions (3 x larger than France) to me seems quite odd ... at the time of 'only' 66 million years ago.
  
  The show that I watched had the theory that the extension event may have been a 'worst of two storms' ... the volcano (I have problem using the term 'volcano' with an event that big) followed by the asteroid impact.
3. Re:So - an impact of an asteroid.... by FudRucker · 2014-12-20 04:51 · Score: 1
  
  yup, thats what i was thinking, the meteor impact was significant enough to cause volcanoes world wide to go spewing up their stuff
  
  --
  Politics is Treachery, Religion is Brainwashing
4. Re:So - an impact of an asteroid.... by turkeyfish · 2014-12-20 11:39 · Score: 1
  
  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.
5. Re:So - an impact of an asteroid.... by turkeyfish · 2014-12-20 11:56 · Score: 2
  
  The only problem with that is that some volcanic activity predated the bolide impact.
6. Re:So - an impact of an asteroid.... by Attila+Dimedici · 2014-12-21 04:12 · Score: 1
  
  It would have been nice if the article had actually said that.
  
  --
  The truth is that all men having power ought to be mistrusted. James Madison
7. Re:So - an impact of an asteroid.... by RockDoctor · 2014-12-22 21:53 · Score: 1
  
  It does say that.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
8. Re:So - an impact of an asteroid.... by RockDoctor · 2014-12-22 21:59 · Score: 1
  
  The are proposing that this strike didn't have any secondary effects - such as volcanoes, earthquakes and the like?
  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 Canada, probably down to Paraguay, possibly well into Africa), and these minor effects are not a matter of dispute at all.
  
  IMO ... such a LARGE impact would have ramifications for MANY years to come.
  You've missed out a factor of 100,000 or so. The evidence from the ground is that it took several millions of years for the biological diversity of the planet to return to pre-impact levels (and then with a changed cast of dinosaurs, increased mammals, and a severely changed marine microflora and somewhat changed invertebrate fauna).
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
9. Re:So - an impact of an asteroid.... by RockDoctor · 2014-12-22 22:04 · Score: 1
  
  That's not the only problem. Most of the world didn't have significant volcanism before, during, or after the impact. The areas that did have volcanism - say one eruption every 1,000 years, per volcano - carried on with that at with a barely detectable difference. Much the same for earthquakes - only those areas prone to earthquakes before the event had earthquakes, and within a few thousand years (probably) after the impact even the area around the impact would have settled down within a millennium or two. (It would have been pretty wild for the first few hundred years though!)
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
10. Re:So - an impact of an asteroid.... by Attila+Dimedici · 2014-12-22 22:44 · Score: 1
  
  I just re-read the article. It says that the eruptions began before the "extinction event", but do not say when the asteroid struck relative to either the eruptions or the "extinction event."
  
  --
  The truth is that all men having power ought to be mistrusted. James Madison
11. Re:So - an impact of an asteroid.... by RockDoctor · 2014-12-22 23:47 · Score: 1
  
  OK ; maybe I'm a bit too close to the data to read the article without bringing knowledge from other areas to bear. The sequence as best we can determine so far is :
  (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-lived ones, it is possible that (2) and (3) are more like :
  (2) as above;
  (2a) +months to 1 year : direct impact damage, fire and starvation do for large dinosaurs ; small dinosaurs and other meso-fauna survive ; dung beetles can't find enough fresh poo piles ;
  (2b) +10 years : ocean pH has dropped by 3 units (1000x more acid) ; major extinctions of marine microflora ; seeds from previous flora are germinating, but with an absence of large herbivores, there are drastic ecological changes (compare what happened to the US/Canadian steppes when the bison was almost extinguished).
  (2c) +20 years : ocean pH rebounds by 1 unit, but many large marine life forms starving to death (or reproductive inability - same thing).
  [...] continuing series of sequels for millennia.
  Disentangling such a sequence will be a real challenge, given that in deep marine sediments (our most stable environment, where you're likely to get the most consistent records without storms taking out the critical metre of sediment), it's perfectly possible to have bioturbation (worm burrows) stir things up through a metre of sediment thickness - a good million years worth. Of course, we could look at a K-Pg analogue of the Euxine Sea (a.k.a. "Black Sea" ; the archetype euxinic basin where the bottom waters are nearly sterilised by hydrogen sulphide because of restricted water circulation) if we (1) wanted to look at only planktonic organisms and (2) we could find such a basin (any suggestions? I don't know of one off-hand, though I've not studied the question. When I'm working next year in the Black Sea, I'll maybe do a literature search).
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Things happen - multiple things by Anonymous Coward · 2014-12-20 04:35 · Score: 0

I thought it was already proven that dinosaurs started to die off and the meteorite was just the knock out blow.
Probably a mix by Doghouse13 · 2014-12-20 04:58 · Score: 3, Interesting

Not the first time I've heard this suggested. But then, given how long the dinosaurs survived, it seems intuitively that it must have taken something highly improbable - a "perfect storm" of disasters - to disrupt ecosystems enough to shift them worldwide.
Massive Volcanic Eruptions Accompanied Dinosaur by Anonymous Coward · 2014-12-20 05:38 · Score: 0

Along with at least one, perhaps as many as three, bolides hitting a sub-surface carbonate shelf at 50 km/sec.
My money is on the meteor.
scentists by Anonymous Coward · 2014-12-20 06:08 · Score: 0

Are not scientists tired of guessing how dinosaurs went extinct? It is all going to be theory since there will be no way to ever prove it. And while it could be interesting, it dose not matter to anyone.
1. Re:scentists by epyT-R · 2014-12-20 06:13 · Score: 2
  
  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.
2. Re:scentists by Hognoxious · 2014-12-20 13:57 · Score: 1
  
  We'll be very interested if they come back.
  Then we'll be interested in how they taste.
  
  --
  Confucius say, "Find worm in apple - bad. Find half a worm - worse."
Re:So it wasn't global warming? by Anonymous Coward · 2014-12-20 06:10 · Score: 0

It was degenerate behavior. You've read jurassic park right?
Statistically not drastic by Celarent+Darii · 2014-12-20 08:28 · Score: 3, 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
1. Re:Statistically not drastic by Celarent+Darii · 2014-12-20 10:01 · Score: 1
  
  That should be km^3 of course, silly.
2. Re:Statistically not drastic by Anonymous Coward · 2014-12-20 14:47 · Score: 1
  
  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 used due to a complete lack of historical gas measurements.
  What seems to be the key in regards to the Deccan Traps is not massive scale compared to what we have seen in historical time, but rather continuous activity, which prevents climate recovery between eruptions. If the climate effect lasts for 3 years after the eruptions (we have measurements to support this claim), we can easily handle one such eruption each century, but one such eruption every year would be problematic and would probably accumulate nasty effects.
  
  And yet the impact of Bardarbung on earthly climate is close to negligible
  First of all, the name is Bárðarbunga. I can understand replacing the soft D with a regular one, but the trailing A shouldn't be missing.
  Iceland suffers from extreme levels of sulphurdioxide. The threshold for dangerous concentration is 600(microgram/m^3, if I recall the unit correctly) and more than 4000 has been recorded in populated areas. Luckily the eruption is in an unpopulated area the dominating wind direction aims away from most people. Acid rain with a pH value of 3.5 has been recorded.
  The only climate effect I have seen reported outside Iceland is a strong sulphuric smell in Norway, which made people call the emergency line.
  The main reason for the effects to be local is the lack of power of the volcano. Right now it is more or less just leaking outside the main caldera, which mean whatever comes out stays at low altitude. However if the main caldera erupts, then it will likely shoot high into the air, disturb planes and spread over a large area. The caldera has lots of earthquakes, often more than one M5+ (compare that to the M6 earthquake, which put California in a state of emergency!), yet it has been doing that for more than 100 days now and there are still no signs of an actual eruption and it is an open question if there will be one. Volcanoes are perfectly happy sleeping for centuries and earthquake measurements started during the cold war. In other words we have little historical knowledge of earthquake activity when volcanoes aren't erupting, only that they seem common (though M5+ is not common).
3. Re:Statistically not drastic by Celarent+Darii · 2014-12-20 23:25 · Score: 1
  
  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.
4. Re:Statistically not drastic by RockDoctor · 2014-12-22 22:12 · Score: 1
  
  It caused enormous damage
  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.
  
  --
  Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
Watch RadioLab Live: Apocalyptical by Anonymous Coward · 2014-12-20 09:52 · 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 time previous to that event seems irrelevant. Interesting, but not plausibly world-wide extinction interesting.
Old, old info by Anonymous Coward · 2014-12-20 12:15 · Score: 0

Not only is this old data, but it was also shown that the likely _cause_ of said volcanic activity was the impact which occurred on the opposite end of the globe.
This is like saying that a person who dies in a car wreck was killed by both the wreck itself and the steering wheel crushing his chest.
exstinction by Anonymous Coward · 2014-12-20 13:14 · Score: 0

uh huh.?
sole cause ? by Anonymous Coward · 2014-12-21 03:22 · Score: 0

All the stuff flash burned (and some impact of supersonic compression wave within some distance, and tidal waves too of monumental size) then all the stuff thrown into the atmosphere to block the sun for years(decades?) ...
So tectonic disruption causing crustal instability leading to massive increase in vulcanism (and all its side-effects)- NOT part of the same event ???
Fools! by Anonymous Coward · 2014-12-21 06:39 · Score: 0

It was Xenu!