The asteroid that hit earth 66 million years ago appears to have caused large amounts of magma to spew out of the bottom of the ocean, a new study of seafloor data finds.
The discovery, described today in the journal Science Advances, adds to the picture of an extinction event that was as complex as it was deadly.
For decades, researchers have pointed to a cataclysmic asteroid crashing into the planet as the reason the dinosaurs, and many other species of life on Earth, were wiped out during the Cretaceous-Paleogene (K-Pg) extinction event. That impact, which scientists think left the roughly 110-mile-wide Chicxulub crater in the Gulf of Mexico, would have vaporized living things nearby and sent choking clouds of debris into the air, obscuring the sun.
But scientists have also pointed to another culprit: the Deccan Traps in present-day India, one of the largest volcanic provinces in the world, which just happened to be very active at the time of the extinction event. The ash and noxious gases from the Deccan Traps are really what killed the dinosaurs, some scientists say, downplaying the asteroid's role.
"People still argue about which one was actually the primary driver of environmental changes that resulted in the death of dinosaurs," said senior author Dr. Leif Karlstrom, an earth scientist at the U. of Oregon.
Researchers have also suggested that perhaps the two were connected — perhaps the asteroid triggered Deccan Trap volcanism, producing a brutal one-two punch that ultimately knocked out roughly three-quarters of the earth's plant and animal species. But recent work has shown that the traps started spewing roughly a quarter-million years before the asteroid hit, Dr. Karlstrom said.
Yet, scientists have wondered if there might indeed be some kind of connection between the two. And lead author Dr. Joseph Byrnes, a geophysicist at the U. of Minnesota, realized something: If the asteroid impact had had a major impact on volcanism at the time, that effect should have shown up in the activity along the Earth's mid-ocean ridges. So he and Dr. Karlstrom went looking for it.
As we've discussed here at Partial Ellipsis of the Sun before, the mid-ocean ridges are long cracks in the Earth's crust at the bottom of the ocean floor where tectonic plates meet. As the plates pull apart, hot magma rises up between them, flowing out on either side of the crack before cooling, creating new seafloor in the process. With more than 40,000 miles of ridges, this network of cracks forms the longest mountain chain on earth.
Scientists used magnetic data compiled by other researchers and combined it with another data set showing the gravitational field of the surface beneath the ocean. The stronger the gravitational field in a given spot, the more mass there is.
"We have a topographic map of the Earth's surface and we have topographic maps of Mars and Venus, but we don't have that for the ocean floor," Dr. Byrnes said. "We have it for places where people have taken ships, but it would take something like 900 years to survey the whole ocean floor. It's just too resource-intensive — so we have to use the gravitational anomalies as a proxy."
The graph below shows a spike in the creation of new seafloor about 66 million years ago. That's when the Chicxulub asteroid struck the Earth, wiping out the dinosaurs. The impact also instigated the release of massive amounts of magma.
Sure enough, the scientists found that at the time the asteroid hit the Earth, there was a sudden surge in the magma pouring out of these mid-ocean ridges, which put out on the order of a hundred thousand to a million cubic kilometers of volcanic material. That's not too far behind the estimated several million cubic kilometers or so of magma produced by the Deccan Traps.
It's possible that the powerful seismic waves produced by the impact triggered the release of reservoirs of magma beneath the surface, Dr. Karlstrom said. And if it affected the mid-ocean ridges this way, it could have played a similar role in the Deccan Traps, triggering even more volcanism than before.
The mid-ocean ridges, then, could be a bellwether for a similar phenomenon occurring in the already-active Deccan Traps.
But did that marine magma release do any damage of its own? While it's unclear whether this extra load of ocean floor magma worsened the extinction event, it could potentially have played a role by further acidifying the oceans. Previous work indicates that marine species that were more sensitive to ocean acidification were worse hit by the extinction event. But probing that possibility will take more research, the scientists added.
"That's what we need to work on next, I would say: trying to tease out what the effects on the environment were of the volcanic activity," Dr. Byrnes said.
Thoughts on this new data? Have you been to the Deccan Traps?
Steph
Speaking of stitches, here's the full quilt my friend made:
The discovery, described today in the journal Science Advances, adds to the picture of an extinction event that was as complex as it was deadly.
For decades, researchers have pointed to a cataclysmic asteroid crashing into the planet as the reason the dinosaurs, and many other species of life on Earth, were wiped out during the Cretaceous-Paleogene (K-Pg) extinction event. That impact, which scientists think left the roughly 110-mile-wide Chicxulub crater in the Gulf of Mexico, would have vaporized living things nearby and sent choking clouds of debris into the air, obscuring the sun.
But scientists have also pointed to another culprit: the Deccan Traps in present-day India, one of the largest volcanic provinces in the world, which just happened to be very active at the time of the extinction event. The ash and noxious gases from the Deccan Traps are really what killed the dinosaurs, some scientists say, downplaying the asteroid's role.
"People still argue about which one was actually the primary driver of environmental changes that resulted in the death of dinosaurs," said senior author Dr. Leif Karlstrom, an earth scientist at the U. of Oregon.
Researchers have also suggested that perhaps the two were connected — perhaps the asteroid triggered Deccan Trap volcanism, producing a brutal one-two punch that ultimately knocked out roughly three-quarters of the earth's plant and animal species. But recent work has shown that the traps started spewing roughly a quarter-million years before the asteroid hit, Dr. Karlstrom said.
Yet, scientists have wondered if there might indeed be some kind of connection between the two. And lead author Dr. Joseph Byrnes, a geophysicist at the U. of Minnesota, realized something: If the asteroid impact had had a major impact on volcanism at the time, that effect should have shown up in the activity along the Earth's mid-ocean ridges. So he and Dr. Karlstrom went looking for it.
As we've discussed here at Partial Ellipsis of the Sun before, the mid-ocean ridges are long cracks in the Earth's crust at the bottom of the ocean floor where tectonic plates meet. As the plates pull apart, hot magma rises up between them, flowing out on either side of the crack before cooling, creating new seafloor in the process. With more than 40,000 miles of ridges, this network of cracks forms the longest mountain chain on earth.
Scientists used magnetic data compiled by other researchers and combined it with another data set showing the gravitational field of the surface beneath the ocean. The stronger the gravitational field in a given spot, the more mass there is.
"We have a topographic map of the Earth's surface and we have topographic maps of Mars and Venus, but we don't have that for the ocean floor," Dr. Byrnes said. "We have it for places where people have taken ships, but it would take something like 900 years to survey the whole ocean floor. It's just too resource-intensive — so we have to use the gravitational anomalies as a proxy."
The graph below shows a spike in the creation of new seafloor about 66 million years ago. That's when the Chicxulub asteroid struck the Earth, wiping out the dinosaurs. The impact also instigated the release of massive amounts of magma.
Sure enough, the scientists found that at the time the asteroid hit the Earth, there was a sudden surge in the magma pouring out of these mid-ocean ridges, which put out on the order of a hundred thousand to a million cubic kilometers of volcanic material. That's not too far behind the estimated several million cubic kilometers or so of magma produced by the Deccan Traps.
It's possible that the powerful seismic waves produced by the impact triggered the release of reservoirs of magma beneath the surface, Dr. Karlstrom said. And if it affected the mid-ocean ridges this way, it could have played a similar role in the Deccan Traps, triggering even more volcanism than before.
The mid-ocean ridges, then, could be a bellwether for a similar phenomenon occurring in the already-active Deccan Traps.
But did that marine magma release do any damage of its own? While it's unclear whether this extra load of ocean floor magma worsened the extinction event, it could potentially have played a role by further acidifying the oceans. Previous work indicates that marine species that were more sensitive to ocean acidification were worse hit by the extinction event. But probing that possibility will take more research, the scientists added.
"That's what we need to work on next, I would say: trying to tease out what the effects on the environment were of the volcanic activity," Dr. Byrnes said.
Thoughts on this new data? Have you been to the Deccan Traps?
Steph
Speaking of stitches, here's the full quilt my friend made:
Never been to the Deccan traps, which sound like a drum set of a certain record label.
ReplyDeleteIs there any evidence for seismic waves setting off magma flows, as speculated above? Did the Chicxulub meteorite set off magma flows locally, in the Yucatan? (If not, why not?)
I don't have a good intuitive feel for the behavior of magma. What happens when you drill down into a magma pocket, like the Iceland Deep Drilling Project? Is it under enough pressure to flow up the hole? I don't think that happened, so what causes magma to flow up and out of volcanoes and mid-ocean rifts? And I'm still bugged by the lack of radioactivity around volcanoes and geysers and other geothermal features, given that all that heat is the product of radioactive decay.
I believe the "change in percentage of seafloor that is anomalous" jump from 4% to 8% (as seen on the graph above) is the evidence the authors are using for those magma flows. It is likely they would be both local and global.
DeleteThis article describes steam flashing when the constantly circulated drilling fluid (mostly water) hits the magma.
Convection currents are conventionally (and convectionally) considered to be the driving force of plate tectonics and mid-oceanic rifting.
There is some radioactivity around volcanoes and geysers, though it is less than expected. A conundrum, for sure!
There is a paper discussing radioactivity at Yellowstone (note that it's dated 1909).
BOW WAVES
ReplyDeleteWait a minute. The Moon's shadow may be moving supersonically through the Earth's atmosphere, but it's not a thing; it's not displacing the molecules in the atmosphere like a speeding boat or plane does. If I stand here on Earth and aim my laser pointer at the Moon and sweep it really fast across the lunar surface in less than 10 msec, I (theoretically) see a red dot moving across the moon faster than the speed of light. Einstein doesn't roll over in his grave because I haven't accelerated any thing to that speed. I'm not saying there weren't electronic disturbances in the ionosphere when the moon blocked the sun, but the "bow wave" explanation doesn't feel right.
Delete(I wonder what Cat Stevens would say about being followed by a moon shadow?)
jan, I had the same thought about Cat Stevens.
DeleteMaybe this will shed some light.
Yeah, I read the Sky & Telescope article (there was a link to it from the YouTube page above. I understand that there's a wave of ionospheric disturbance that's associated with the Moon's shadow as it passes over. What I'm objecting to is the characterization of this as a bow wave, with the implication of compression of the medium ahead of an object moving through the medium. I don't think that's what's happening here.
DeleteHere's the original report. My understanding of the physics doesn't allow me to say anything more cogent than just repeating my skepticism of the use of the term "bow wave".
DeleteHere's a counter-argument that just occurred to me. It may be completely specious, given my amateur credentials in physics, but, hey, we're among friends. The article describes the moon's shadow as moving supersonically through the ionosphere (and the rest of the atmosphere, too, of course). If what they recorded was really a bow wave, it should then have been a shock wave, as the disturbing phenomenon moved faster than the speed of sound in the medium, essentially piling up the bow waves ahead of it into a shock front. Did anybody hear a sonic boom as the eclipse passed? I didn't think so.
Delete[Of course, given the authors' affiliation, I probably shouldn't be needling them like this...]
DeleteI didn't hear a sonic boom, but some young people on the hill above us let out loud screams.
DeleteMy very bad stab at this: the moon's shadow is not a thing, but it creates reactions in real things in the ionosphere. Technically UV from the sun creates reactions, nighttime or the eclipse changes those reactions. Eclipse is a sped up version of day into night.
The question I have is does this merely imitate the pattern of a bow wave, or does change to one ionospheric particle affect its neighbors? Maybe that's what Jan is asking. The next video in Youtube purports to explain, but doesn't really "shed any light". But I enjoyed how a computer voice misinterprets written text. And you doubtless enjoyed me showing my ignorance.
One wonders why they used a text-to speech system on that slide show?
DeleteAnyway, imagine flying over a body of water in an invisible plane, strafing the surface with a machine gun firing invisible bullets straight down. Someone floating in a balloon over the water would see a pattern of ripples in the water that might resemble those formed by an object moving rapidly across the surface horizontally. No such object exists, of course. There's no airplane-speed boat causing a bow wave, it just looks that way. QED.
Ah, I am getting your question now, jan. Sorry, I read it too quickly before. Indeed, it's not a true bow wave. I bow to you and physics ;-).
DeleteDeck 4, eco! Thanks for that odd slide show.
{Though, Maizie says "Bow wow wow!"}
P.S. I enjoyed the original research paper's inclusion of a "Plain Language Summary."
DeleteMight I offer a clearer analogy (I think): if a moving boat suddenly stopped in the water the bow wave would continue for some distance. But if the moon were to suddenly stop I don't think the ionospheric changes would continue in front of its path.
DeleteMaybe I'll think more clearly when I wake up.
I'm not sure that's right, eco. If the Moon were to suddenly stop, the pattern of convective disruption might well continue for a bit, like a bow wave would. (Or, like the ripples in a pond would, long after a stone has sunk.)
Delete(Speaking of the Moon suddenly stopping, have you guys read Neal Stephenson's Seveneves yet? What are you waiting for???)
I don't see how the convective disruption could continue, the loss of solar radiation wouldn't be moving forward, so why change?
DeleteIf the pattern did continue then I don't see why you don't like the comparison to a bow wave? The force creating the wave is not in direct contact, but it is still the cause.
Those Deccan Traps rocks could easily have been mistaken for sedimentary layers from afar. . .
ReplyDeleteThe Deccan traps are likely associated with movement over a hot spot, creating the Traps which are the size of Oregon and Washington states combined. Fascinating stuff.
DeleteAnd, as long as we're picking nits, let's celebrate victory for the Oxford comma!
ReplyDeleteYeah, Oxford comma! Though that new semi-colon revision is a little strange.
DeleteMy stupid question of the day somewhat related to this article: as I understand it we only know about exoplanets within this galaxy because they dim the light of their star as they pass in front of it. And when astronomers observe this dimming over regular intervals they assume there is a planet.
ReplyDeleteIssue #1: For the planet to dim its star, doesn't the orbit of that planet have to be nearly co-planar with our line of site? If we were "looking down" at the planet's orbit, or even if it were off by just a few degrees we'd never see it pass in front of the star.
Issue #2: We've only had the capacity to observe this for a few years. Jupiter's revolution takes almost a dozen years, Saturn's nearly 30 years, and Uranus is a whopping 84 years, we haven't had the time to watch one revolution.
All of this is my way of wondering how many planetary systems aren't seen, either because they don't align with our tastes, or we just haven't been looking long enough?
All valid questions, eco, especially about the planet being co-planar with our line of sight. I suppose the size of the planet could also factor in here. And looking for much longer over longer revolutions seems important, too.
DeleteFavorite line from the article you cited: "This is very cool science." We don't see that unabashed enthusiasm enough!
I don't circulate with cosmologists much, but one (with many years of experience) I met a few years ago said these are very exciting times for the profession. Hubble and various earth bound telescopes, as well as better analytic tools, are providing more data than they can process, many discoveries ahead.
DeleteThis is a very cool discovery by an amateur astronomist.
ReplyDeleteThis comment has been removed by the author.
DeleteWow!
DeleteDamn, I wish I knew why the same HTML that works on my laptop doesn’t work when I write it on my phone! (Which I’m using because our corporate overlords are blocking access to PEOTS!)
Anyway, here’s Tilley’s original announcement:
“http://skyriddles.wordpress.com/2018/01/21/nasas-long-dead-image-satellite-is-alive/”
The corporate lords are blocking PEOTS?! How strange.
DeleteHis account of the discovery is thrilling. Thanks for sharing, jan.
They’re blocking all posting to social media. And making sure that, between patients, we take our mandatory training in human trafficking. (Prevention or detection, I presume. )
DeleteWhile the sequence is cool and exciting, sort of a CSI (Catch Satellite Image) for astronomy buffs, there was one telling line in the NASA article: “Does anyone happen to have a 4 mm tape cartridge reader that will work on a modern Linux workstation and a 16-year-old data tape and not disintegrate it?”
DeleteWhile we think there is some sort of permanence to what we do, information can disappear - or at least not be read - in a very short time. Time to pull out the chisels and stones.
And then along comes a roaring river. . .
DeleteDon't leave your rocks out.
DeleteImpossible.
DeleteDigging up dirt on dirt. The article links to the original paper (with big sciencey words) for you smart people. Reminds me of the theory I read decades ago (I think in Scientific American) that the polio crisis of the 19th-20th Centuries was largely due to children no longer playing in (and eating) dirt. I suppose that's similar to the Hygiene Hypothesis.
ReplyDeleteAnd little boys don't need to M*A*S*H ants.
eco, a dirty post on Valentine's Day? How risqué!
DeleteI especially enjoyed the ant triage.
On my ambulance squad, too, we never transport patients who’ve had 5 or 6 legs ripped off.
DeleteGood call.
Deletejan, how often is your ambulance squad on duty?
Jan, not all of us are so discriminating.
DeleteOur squad is on duty 24/7/365, of course. Personally, I do a 12-hour shift each week, Wednesdays, from 7 pm - 7 am. Plus, we rotate the Saturday day shift each quarter, so I'm on tomorrow from 7 am - 7 pm. (Although, that Saturday rotation will soon become a 24-hour shift, due to lack of coverage.) We're a pretty quiet town, averaging about 1000 calls a year, which breaks down to about 3 calls a day. Figure 2 calls during a daytime shift, 1 call at night. Random variation, of course, means that we get no calls some shifts, while others we're busy the whole time.
Deletejan, great that you do that. All volunteer, I presume?
DeleteIt was all volunteer, from our start in 1954 until a few years ago. We now hire a couple of per diem EMTs to cover the Tuesday day shift. That's likely to expand, but we'll run into funding trouble, since we don't bill, either. We get about a third of our funding as from the town, about half from donations to our fund drive, and the rest from companies in town, foundations, memorial contributions, etc. I don't think it's a sustainable model any more. 64 years ago, a lot of people didn't have health insurance that covered ambulance service, and there was no Medicare or Medicaid. On the other side of the equation, the training required for volunteers was much less, just a Red Cross first aid course. Now, there's much less need for a free service, and it's a lot harder to attract volunteers, with around 200 hours of initial EMT training required, not to mention all the continuing education and other obligations.
DeleteSome great points, jan. Any particularly unusual calls during your shift?
DeleteAt 3:00 a.m., everybody's unusual.
DeleteGood point.
DeleteAnd, lest you think I'm advocating EMS service just for those who can afford it, I'm not. Nothing says we can't bill insurance (which people are paying for already, in the form of premiums, taxes, or reduced wages) or the patient, for those without insurance, and just write off unpaid bills. The Medicare or commercial insurance reimbursement rate would cover salaries and expenses just fine, and those dollars would be coming back into our community instead of just going to those municipalities that do bill for service. (Which is pretty much all urban areas, which is where most people live these days.)
DeleteThere are lots of itty bitty Colorado towns with volunteer squads, but it would never fly in Denver or the suburbs.
DeleteMendo Jim, your post disappeared, unfortunately. Here it is with an added link to the EPOD of the Scapegoat Wilderness you cited.
ReplyDelete"Someone has withheld photographs of the Deccan Traps from me for 70 years. They are awesome and sort of ominous.
Another awesome mount is Scapegoat Mountain in the Bob Marshall Wilderness featured on today's EPOD."
Hey, Mendo Jim, I see you tried to post the same words again with no luck. I sent an inquiry to Blogger asking if they know what is going on. Your post is copied verbatim above.
DeleteI had not heard of the Deccan Traps either. I did a poll of geologist friends and no one I asked had either. They do look ominous, layers and layers of igneous rock, posing as "sedimentary."
A test for Mr. Blogger.
ReplyDeleteMJ, that post stayed. Perhaps the needed tweek was tweeked.
DeleteI kept thinking about the Deccan Traps and how forbidding and inhospitable they look. Nobody could live there.
ReplyDeleteIt turns out the area of the Traps (steps), as mentioned the size of Oregon and Washington together, is surprisingly contiguous with the state of Maharashtra.
And I was right, only 112 million people live there.
I just saw a headline, "Turkey denies chemicals in Afrin", but I've got proof right here. "Oxymetazoline HCl" sure sounds like a chemical to me!
ReplyDeleteChemicals: they're everywhere!
DeleteDo sweat the small stuff.
ReplyDeleteDiscouraging words.
Delete"For machines to override human beings, they would have to do every step in society, of digging oars out of quarries and refining materials and building up all the products and everything we have in our lives, and making clothes and food.
ReplyDelete"That would take hundreds of years to change the infrastructure," Wozniak explained. (Emphasis mine.)
Oars from quarries?! Would that be a sunk cost?
DeleteTwo facts that WW knows well: limestone quarries started out as shells, and oars are used in shells, so, sure. (That's using my scull!)
Deletejan, touché!
DeleteAt least we avoided a row here.
DeleteFor the moment, AI is only as dangerous as humans try to make it. Which is dangerous indeed.
WW: what is your new thumbnail? I can't help anthropomorphizing a Mark Rothko-like face in the lower left hand corner.
eco, re: AI: indeed.
DeleteMy thumbnail is part of a quilt my friend made to celebrate new beginnings. The diagonally connected pieces are so cool. I can see that face, with careful use of AI ;-).
I posted an image of the full quilt at the end of this post. Extraordinary work of art!
DeleteAny intelligence I have is certainly artificial.
DeleteCongratulations to your friend on her quilt; it's a waning art, though there is still a quilting supply store in my office complex.
DeleteInteresting that at the larger size the profiled face is less apparent, but above and to the right near the middle is (to me, at least) a very tortured face.
eco, I don't see that face clearly but I certainly see the tortured and tortuous face in your new thumbnail.
DeleteMaybe this snip helps?
DeleteAh, yes. Perhaps Jesus Christ's face on the cross...That perhaps fits with her quilt name of "New Beginnings." She is starting a new job tomorrow and wanted to complete the quilt before Day 1.
DeleteA start is born
ReplyDeleteMy curiosity vastly outweighs my knowledge, but I remain skeptical about the Big Bang Theory, though I enjoy the show once in a while. I am particularly unconvinced that everything was squeezed into a ball the size of Trump's head - I could buy the universe fit inside his ego.
ReplyDeleteI know this comports with observations and the known rules of physics, but since we don't know what most of the universe is made of, which might put a very different spin on our rules of physics .... am I the only doubter?
Not at all -- No singularity needed.
DeleteThanks WW, now I have to more study in quantum mechanics.
DeleteYou knew that was coming.
Major guffaws, eco.
DeleteMy second favorite bumper sticker:
DeleteQuantum mechanics do it with uncertainty.
Yes!
Deletejan, I've forgotten your favorite bumper stcker. . .?
Your karma ran over my dogma.
Delete("Your" and "my" can be swapped in various combinations.)
Thanks, jan.
DeleteI could have done a search, but where's the fun in that?
Previously unknown colony of 1.5 million penguins found in Antarctica. Satellites detected their guano. Given the amount of shit being promulgated there, it's surprising they didn't provide better estimates of the crowd at Trump's inauguration last year.
ReplyDeleteEverybody poops.
DeleteI always find it interesting that there are so many words for excrement. People could almost do their Masters' feces on those terms.
When people ask about putting composting toilets in their houses I caution that health departments are very skittish, "Everyone's looking out for #2."
DeleteThank you, please tip your waiters.
I just can't hear the word without seeing Peter Sellers and Keenan Wynn in Dr. Strangelove: "Now listen, Colonel Bat Guano, if that really is your name..."
DeleteBat a thousand or bat guano?
Deleteeco, re: your comment at Blaine's -- just heard the news about you-know-who. . . Dental surgery kept me in a bit of a fog.
ReplyDeleteI wish I were clever enough to invent this stuff; and I really wish all this was imaginary.
DeleteAnd sorry you had dental surgery, there are much better ways to get into a fog.
DeleteThanks, eco. That's for sure. Doing much better now after some painful hours.
DeleteJapanese "Bond" Volcano erupts
ReplyDeleteBond is a really hot lava.
DeleteI know I've posted the video before, but we always have to be on the look out for B-52's. I went to a dance party of theirs a few years after this video was shot, they were in color by then.
That hair!
DeleteNew post on "Ice-VII: Deep Ice, Tectonic Slabs, and Diamond Inclusions" is now up.
ReplyDelete