Still, puzzling details abound regarding the end-Triassic mass extinction, such as when fern spores appeared. Ferns are often the first plants to appear after a natural disaster. But in this case, although massive quantities of fern spores coincide with lava flows in some areas, the spike occurs before the extinctions in others.
Other evidence suggested that a huge meteorite strike may have also played a role in the end-Triassic extinction event— akin to the impact that created Chicxulub crater in what is now Mexico's Yucatan Peninsula and is thought to have wiped out the dinosaurs during the Cretaceous–Tertiary (K –T) mass extinction about 65 million years ago. The giant hit that left behind the Manicouagan Crater in what is now Quebec apparently occurred about the time of the end-Triassic extinction. Research eventually showed, however, that collision was about a million years too early to have caused a die-off. But Olsen and his colleagues have investigated a crater of the right age to be the culprit—a hole about 40 kilometers wide discovered in France at Rochechouart.
Yet, a number of questions remain about the impact idea, overall, especially with regard to iridium, the relatively rare metallic element that typically accumulates as a signature layer in the geologic strata and is exposed at such sites . Scientists had apparently found multiple iridium layers, and "since multiple impacts spread over tens of thousands of years seems very unlikely, we became much less enamored of the impact hypothesis, especially because volcanic ashes can produce the same kind on anomaly," Olsen says. Over the past couple of years, though, research has also revealed that one of these iridium layers possessed ratios of other platinum group elements that were much more similar to those associated with meteorites than with most volcanic processes. The results have put the impact hypothesis back in the ring.
The researchers went digging in New Jersey looking for more fern spores, iridium traces and other potential clues that might help resolve all these questions regarding the end-Triassic mass extinction.
The region back then may have been very hot by modern standards, with climate fluctuating between humid and arid. It was covered by small-leaved conifers and was home to herbivorous and carnivorous relatives of crocodilians called the crurotars ans, in addition to small dinosaurs, lizards and the like, Olsen says. Nowadays the area is mostly rolling farmland. The researchers managed to convince the Kells to let the team drill beside the family garage, right next to a cornfield.
'The entire layer cake'
Using a Winkie is relatively inexpensive compared with the average geologic drilling project, and it can drill to a depth of about 150 meters, Olsen says.
The drill uses water for lubrication, leading to muddy jeans and sneakers all around. The engine often proved fussy, stalling when the oil– gas mix wasn't quite right. Still, over the course of a week in August, as cicadas hummed over the chainsaw buzz of the rig's motor, the researchers managed to drill down 40 meters into red mudstone. "We may have lucked out and recovered the entire layer cake—sediment layers deposited before and after the big extinction event as well as those recording the event itself," Kent says.
To see whether the suspected geologic and extraterrestrial events happened before, during and after the mass extinction, Kent will look in the core samples for signs of reversals in Earth's magnetic field, which happen periodically over hundreds of thousands of years. These reversals are captured by magnetically sensitive minerals, which preserve the way Earth's magnetic poles once pointed much like compasses. The regular nature of these reversals make them useful markers of time, and therefore help shed light on when other details found in the same rocks might have happened. By getting a better idea of when any eruptions and impacts might have occurred, the researchers hope to see what events might have directly preceded the end-Triassic mass extinction.
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27 Comments
Add Comment"wanted to discover" would mean that they're a bunch who doesn't work according to scientific principles, no?
Reply | Report Abuse | Link to thisit seems reasonable to conclude that "discover" is here being used as a synonym for "investigate", and that we may read the sentence as " wanted to "investigate" in order to "discover". it is certainly reasonable to assume that a paleontologist, a paleomagnetist, and a geochemist are well-versed in the scientific method.
Reply | Report Abuse | Link to thisContinents cover only a third of the Earth. However, the ocean floor of 200 mya has long since been subducted. Would a marine strike be capable of causing mass extinctions, or would the strike have to occur on shallow continental shelves or land to have an effect?
Reply | Report Abuse | Link to thisit would depend upon the size of the strike. one of sufficient magnitude, ie,a very large asteroid or comet, could throw enough ejecta into the atmosphere to dramatically effect the global climate for a long period of time. it would also cause global tsunamis of such magnitude as to make the phrase "biblical proportions" appear to be a child's wading pool by comparison. enormous areas of coastal, near coastal, and island ecosystems would be entirely destroyed. a VERY LARGE worst case scenario here: http://pinktentacle.com/2010/09/animated-simulation-of-asteroid-hitting-earth/ very well done video simulation.
Reply | Report Abuse | Link to thisthere is also an online, interactive (user sets the parameters [i destroyed myself several times - i was too close]) simulator out there somewhere but i can't seem to find it just now.
ps - found it - http://www.purdue.edu/impactearth/
Reply | Report Abuse | Link to thisI think some features of some animals may also give us clues about what happened. I wonder if birds with a system that absorbs heat from sunlight and frogs with antifreeze blood mechanisms are the result of adaptations to climatic changes of that period?
Reply | Report Abuse | Link to thisThis iPad app shows the three-dimensional magnetic map of the region of impact in the Yucatan peninsula
Reply | Report Abuse | Link to thishttp://itunes.apple.com/us/app/3d-el-crater-de-chicxulub/id556197465?l=en
No.
Reply | Report Abuse | Link to thisRaupian theory was pretty popular about 20 years ago - all major extinctions would uncover a bolide collision in the causation column. It retreated from silver bullet status, but this article is interesting to frame volcanic eras setting up vulnerability to collisions with X.
Reply | Report Abuse | Link to thisПроизошло изменение формы Земли,что изменило скорость вращения Земли вокруг своей оси,угловой наклон.Эти изменения нарушили равновесие в системе Земля-Луна и дальше произошло то,что назвали апокалипсисом.На Земле найден лунный грун-брекчий,на Луне земной грунт а лунный лёд это земная атмосфера.Смену геграфических полюсов Луны доказали сотрудники парижского Института физики Земли.Смена полюсов Земли и Луны произошла одновременно.Всё произошло со скоростью вращения Земли вокруг своей оси и Луны вокруг Земли.В настоящее время вращения Земли вокруг своей оси примерно 1800 километров в час,скорость полёта винтовочной пули примерно 800 километров в час.Сегодня напечатали статью в Нюйёрк Таймс о том,что Земля меняет форму,также есть картинки формы Земли в интернете.
Reply | Report Abuse | Link to this<blockquote>"Also, the scientists will look for carbonate nodules and the density of tiny openings known as stomata on fossil plant leaves. Carbon dioxide captured in the carbonate nodules could give an idea of what the atmospheric gas levels were like back then—higher levels would also leave behind more carbonate nodules and more stomata to absorb the gas."</blockquote>
Reply | Report Abuse | Link to thisI understand higher CO2 levels correlate with <i>fewer</i> stomata, as each can take in more CO2.
What's not well explained in this article, however, is why these researchers would be led to search for evidence of meteorite impact (somewhere) that might have led to the T-J mass extinction.
Reply | Report Abuse | Link to thisThe article subtitle states:
"Western New Jersey holds one of the most visible examples of the Triassic–Jurassic boundary, where evidence could settle the debate about what caused a mega-extinction event that paved the way for the age of dinosaurs."
From this it might be concluded that the debate ensues, considering the 'usual suspects' in mass extinctions. This research does seem to be a bit of a shot in the dark - a search for evidence that might implicate one of the 'favorite' suspects. If I was a meteorite of that period, I'd be looking for a good defense lawyer.
The common problem with investigations of these sorts is that evidenciary data is subject to interpretation, and highly motivated investigators can often build a case against a suspect that might not have otherwise have been the best candidate.
Looks to me like these scientists may have sufficient motive to pin a charge on an innocent suspect - the jury should carefully weigh any evidence they dredge up...
I think the problem is that everyone is looking for a single event that resulted in the extinctions. There could have been a series of impacts that fractured the planet just enough to trigger massive volcanic eruptions. The combination of smaller events would have been enough to cause the extinctions without leaving evidence of one massive event. The smaller events would be spread around the globe and many would no longer be visible.
Reply | Report Abuse | Link to thisIf this happened during the time that all landmasses were closely grouped together, it is likely that the majority of the impacts (if any) could have happened over the world ocean and left few traces for us to find. The traces we find may only be evident in the traces left by the ejecta or that filtered out of the atmosphere over time.
I guess my question would be what triggered the separation of the continents around this time.
You can "want to believe in the Easter Bunny" and that doesn't make you any less of a scientist. So what if they wanted to discover a particular thing? As long as they apply the scientific method and honestly report their results, it doesn't matter.
Reply | Report Abuse | Link to thisThat said, it was obviously just a figure of speech, troll.
It seems a logical conclusion that since a strike caused the demise of dinosaurs and enabled the accent of mammals (MAN), another such strike will end the rein of mammals and enable something else.
Reply | Report Abuse | Link to thisOf course, if we were to divert some R&D money from climate change, to near miss objects, we could possibly change that outcome. Who knows?! GK
Null, Meteor impacts leave a high concentration of rare metals like iridum. It is not just a SWAG.
Reply | Report Abuse | Link to thisThank you for the post for the simulation. It was very frightening/informative, lol. Wonderful work. Kat.
Reply | Report Abuse | Link to thisSorry to wake you up but consider this info below:
Reply | Report Abuse | Link to thisNever underestimate the power of human imagination run wild. They can even make monkeys out of us.
On December 9, 2010 in The New York Times science writer Nicolas Wade wrote: "Anthropologists have been thrown into turmoil about the nature and future of their profession after a decision by the American Anthropological Association at its recent annual meeting to strip the word “science” from a statement of its long-range plan.?
A NY Times (March 12, 1961) article, “There Are Neanderthals Among Us” discussed fossil skeletons found in La Chapelle in Europe that turned out to be those of contemporaries who were bent over from bone disease.
In pro-evolutionist Bill Bryson’s best seller, “A Short History of Nearly Everything” he writes about “The American Museum of Natural History Hall of Human Biology and Evolution in New York that has an absorbing diorama that depicts life-sized creations of a male and female walking side by side across the ancient African plain. The tableau is presented with such conviction that it is easy to overlook the consideration that virtually everything above the footprints is imaginary.”
He asked the curator of the museum and paleoanthropologist, Ian Tattersall, if “he was troubled about the amount of artistic license that was taken in reconstructing the figures,? Tattersall replied, “It’s always a problem in making recreations. You wouldn’t believe how much discussion can go into deciding details like whether Neanderthals had eyebrows or not…We simply can’t know the details of what they looked like… If I had to do it again, I think I might have made them slightly more apelike and less human.”
In 2004 National Geographic tested four paleoartists by giving them the same fossil bones at different times without telling them other paleoartist would be creating drawings from the fossils. The results were that not one of the drawings looked like the others and none of them had any body hair on them!
This whole field has proven again and again that many of these researchers have lied and continue to lie. The most brazen and unfounded theories are proclaimed only to find the research was faked or non-existent.
This is chicanery not science.
This is imagination run wild not science.
This is absolute fraud.
Talk about honesty in the "sciences."
Also, the scientific method is always looking to 'discover' ... something. You always start with a question, do some research, then develop a hypothesis and go from there... they wanted to discover 'if': 'A huge meteorite strike may have helped the dinosaurs rise as well as fall.'
Reply | Report Abuse | Link to thisRelativity's theory seems children's stuff in comparison to this. I do not understand a dot about how to find out what the dinosaurs were doing 200 million years ago. But no doubt there is solid science behind all this. And I mean solid science!
Reply | Report Abuse | Link to thisI suggest an introductory Earth Science textbook if you want to understand how we find out about long past events:
Reply | Report Abuse | Link to this* Physical geology tells us what the Earth was up to. The pattern of creation of new strata (igneous) and wearing down by various forces (sedimentary) is recorded in the rocks.
* Radioactive dating tells us their ages, isotope and abundance data tells us about physical conditions at the time.
* Fossils of various kinds, from dinosaurs to limestone and coal beds, to microscopic diatoms tell us about the living things that were around. Since the fossils are located within the geology in rock beds somewhere, we can place them in history.
In reply to DaniEder (from Plain-2009)
Reply | Report Abuse | Link to thisDear DaniEder: Thanks very much. I appreciate very much your kindness. Even when I am very busy right now, and my main fields of interest are in other areas, I certainly will try to get a basic Earth Science textbook as soon as possible. It is extremely interesting, and I encourage you, and people in these fields, to continue research, and let the world know about it. I was not wrong when I felt there is solid science behind this. Greetings.
The language of "this article is interesting to frame volcanic eras setting up vulnerability to collisions with X" is confusing. A volcanic eruption is not going to make it any more likely to be hit by a meteor. In that sense, volcanic eras do nt set up a vulnerability to collisions.
Reply | Report Abuse | Link to thisHowever, you might mean that the volcanic eruptions -- if there are enough of them -- stress the environment such that the biosphere is close to a mass extinction. Then a metereor impact occurs and provides the final stress/push over the edge. That would be justified in the reading of the article, particularly taken in conjuction with the impact 1 million years prior to the extinction (the Canadian crator) that did NOT trigger the mass extinction. Only when the extensive volcanic activity of Pangea's breakup had stressed the environment were the conditions such that a new meteor impact (the French crator)added enough stress to cause the Triassic mass extinction.
""wanted to discover" would mean that they're a bunch who doesn't work according to scientific principles, no?"
Reply | Report Abuse | Link to thisNo. In this case the researchers have a hypothesis: meteor impact contributed to the Triassic mass extinction. What happens next is that you DELIBERATELY go looking for evidence relating to that hypothesis. You state specifically what that evidence is going to be. So yes, in the vernacular you "want to discover" the evidence: you are looking to find the evidence you have specified that will support the hypothesis. Now, you may very well not get what you "want" and instead find evidence that can't be there IF the hypothesis is true. That is evidence that refutes the hypothesis. All that is required for "objectivity" is to be willing to admit the hypothesis is wrong if that is the evidence you find.
The title of the piece is pure bait-and-switch. There is no discussion of a "meteorite strike" in the body of the article causing the 200 million year old mass extinction except for the very first non sequitur sentence.
Reply | Report Abuse | Link to thisSorry about my comment. Just realized I'd read only the first webpage - hadn't notice there were two others!
Reply | Report Abuse | Link to thislucaspa quite correctly states:
Reply | Report Abuse | Link to this"All that is required for "objectivity" is to be willing to admit the hypothesis is wrong if that is the evidence you find."
There-in squats the big fat toad.
Some researchers would rather reject evidence discarding it as bad data, then face the collapse of their hypothesis. Ego can accomplish this, while the researcher consciously and happily continues - thinking he is doing good science.
It is why independent replication is so essential and skeptics so valuable. It is a vital purifying fire. Without it... we are no longer discussing science. GK