Geologists Find Massive Impact Crater in Greenland Under a Mile of Ice
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That was an interesting watch!
Maybe it is the one that got the dinosaurs.
muddymooose
Hoopy Frood
The 65 million-year-old dinosaur-killer created the Chicxulub crater on the Yucatan Peninsula of Mexico. This one is estimated to be as recent as 12,000 years ago. If so it may have been largely responsible for the devastation of North American megafauna and the Clovis culture around that time. More evidence is needed.
what a hole what a hole.
Just wanted to chime in as a geologist:
So there's this really weird, somewhat inexplicable cold period called the Younger Dryas that crops up in a lot of the ice cores we drill, going back about 12 Myr. It's weird because it's brief and extreme - and generally climate behaves according to a regular, slow-moving beat (I think Scott talked about Milankovitch cycles in the vid). There's only two things that can cause fast and dramatic climate change: Volcanism and impacts. The former is hard to argue for, because the kind of volcanism that causes significant global changes is associated with these things we call "flood basalts," which are literal hundreds of thousands of cubic kilometers of basalt that erupt and outgas volatiles - and the youngest one of these we have is over in India (the Deccan Traps), and that's about 65 Myr old. They also occur over a fairly long period of time - a couple thousand years - that would easily have been preserved in the cores we have. Intense enough, but too slow and difficult to do nowadays.
With this in mind, some folks have taken to concluding that a comet or asteroid smacked into the ice sheets that were covering North America at the time, which neatly explains the extinction of megafauna and the total lack of an impact crater from that timeframe. Well, now we have a potential impact crater. It doesn't explain everything, but it's probably going to raise a lot of interest and generate a wealth of research. Even if it turns out to be from an older event, it's still another page we can add to Earth's history book.
I think the method of discovery is just as cool as the impact crater itself! Sifting through "garbage" data to find something new is one of the greatest things we do as scientists. I'm sure a lot of overflight data is getting a second look as we speak, and there is much to be learned from it.
So there's this really weird, somewhat inexplicable cold period called the Younger Dryas that crops up in a lot of the ice cores we drill, going back about 12 Myr. It's weird because it's brief and extreme - and generally climate behaves according to a regular, slow-moving beat (I think Scott talked about Milankovitch cycles in the vid). There's only two things that can cause fast and dramatic climate change: Volcanism and impacts. The former is hard to argue for, because the kind of volcanism that causes significant global changes is associated with these things we call "flood basalts," which are literal hundreds of thousands of cubic kilometers of basalt that erupt and outgas volatiles - and the youngest one of these we have is over in India (the Deccan Traps), and that's about 65 Myr old. They also occur over a fairly long period of time - a couple thousand years - that would easily have been preserved in the cores we have. Intense enough, but too slow and difficult to do nowadays.
With this in mind, some folks have taken to concluding that a comet or asteroid smacked into the ice sheets that were covering North America at the time, which neatly explains the extinction of megafauna and the total lack of an impact crater from that timeframe. Well, now we have a potential impact crater. It doesn't explain everything, but it's probably going to raise a lot of interest and generate a wealth of research. Even if it turns out to be from an older event, it's still another page we can add to Earth's history book.
I think the method of discovery is just as cool as the impact crater itself! Sifting through "garbage" data to find something new is one of the greatest things we do as scientists. I'm sure a lot of overflight data is getting a second look as we speak, and there is much to be learned from it.
Interesting find 
The climate models will now be adjusted to suit the new data perturbation <slight sarcasm icon>
The climate models will now be adjusted to suit the new data perturbation <slight sarcasm icon>
Interesting find
The climate models will now be adjusted to suit the new data perturbation <slight sarcasm icon>
Hi OTT, I'm not sure what you mean by 'slight sarcasm' but I'm gonna chime in anyway, because teacher. (Elder daughter once said "Dad's a teacher, and anywhere is the classroom." Made me proud.
) I suspect you already know all the stuff below, but...some people don't.You'll hear people say "Science can't make up its mind, it keeps changing what it says." That's exactly what science is supposed to do. Science is not absolute and it's not supposed to be absolute. It would shock some people to hear that we don't know, in an absolute sense, that atoms exist (it's called atomic theory for a reason). When you watch Deadpool on TV, sadly, you don't actually see Morena Baccarin. You see an image that has been created by a complex system. By the same token, no one has ever seen an atom; what we've seen are images, consistent with atomic theory, created by electronic/mechanical devices.
Suppose someone came up with experiments and a theory that didn't use atoms but explained everything that atomic theory does, and also explained stuff like dark matter. Eventually the new theory would supplant atomic theory. Some diehard atom-believers would undoubtedly have to die off before the new theory was completely accepted, but science goes with the evidence. When more evidence is obtained that clearly contradicts an accepted theory, the accepted theory must be either modified or discarded.
But such a scenario is highly unlikely. Proper atomic theory has been around for over two centuries. It's been modified extensively to explain new data and results--- "all atoms of a given element are identical" and "atoms can't be created or destroyed" are not quite true --- but the basic concept of tiny particles that remain the same in chemical reactions is still correct.
All this is to say that the climate models will be changed as new data is obtained, but the basic idea that human activity is responsible for the latest changes in climate will remain.
Quiz on Friday. Read the rest of Chapter 23 by then.
Best -- Terry
Hi prf. I am a scientific person and an engineer and am well aware of how simulations, and indeed science, work and are refined. My signature below is an indication that I find it mildly amusing how much faith people put in simulations at times, and just a gentle reminder that the proof of the pudding is in the eating as they say. A circuit that I designed last year would not have been possible without high-fidelity signal integrity simulations and the fact it worked as designed on first attempt shows the value of simulations.
The "slight sarcasm" comment indicates my concern with climate-related simulations. There are a whole lot of factors withing the simulations that can be "tuned" to provide an outcome matched to the data. With so much money in the industry at stake the chance of people selecting a set of parameters that satisfy their final outcome, as they see it and possibly to their best advantage, is not insignificant. Reasons could be confirmation bias, inventors enthusiasm, bad science, greed, or anywhere in between. The amount of money being spent in that domain is muddying the waters somewhat.
Thanks for taking the time to put your thoughts on paper. It also encouraged me to elucidate my views.
The "slight sarcasm" comment indicates my concern with climate-related simulations. There are a whole lot of factors withing the simulations that can be "tuned" to provide an outcome matched to the data. With so much money in the industry at stake the chance of people selecting a set of parameters that satisfy their final outcome, as they see it and possibly to their best advantage, is not insignificant. Reasons could be confirmation bias, inventors enthusiasm, bad science, greed, or anywhere in between. The amount of money being spent in that domain is muddying the waters somewhat.
Thanks for taking the time to put your thoughts on paper. It also encouraged me to elucidate my views
.
Winston
Lorenzo von Matterhorn
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Same with me. Just noticed your post when posting today about the second crater found. I don't want to open a can of worms which is what this topic has always brought here, so I'll simply post this which I found long ago:
Verification, Validation, and Confirmation of Numerical Models in the Earth Sciences
Naomi Oreskes; Kristin Shrader-Frechette; Kenneth Belitz
Science, New Series, Vol. 263, No. 5147. (Feb. 4, 1994), pp. 641-646
https://pdfs.semanticscholar.org/c6e1/385abc386c3519175e34ea3c0a68da8b540c.pdf
Excerpts:
Verification and validation of numerical models of natural systems is impossible. This is because natural systems are never closed and because model results are always non-unique. Models can be confirmed by the demonstration of agreement between observation and prediction, but confirmation is inherently partial. Complete confirmation is logically precluded by the fallacy of affirming the consequent and by incomplete access to natural phenomena. Models can only be evaluated in relative terms, and their predictive value is always open to question. The primary value of models is heuristic.
Numerical models are increasingly being used in the public arena, in some cases to justify highly controversial decisions. Therefore, the implication of truth is a serious matter. The terms verification and validation are now being used by scientists in ways that are contradictory and misleading. In the earth sciences-hydrology, geochemistry, meteorology, and oceanography-numerical models always represent complex open systems in which the operative processes are incompletely understood and the required empirical input data are incompletely known. Such models can never be verified.
KILTED COWBOY
Well-Known Member
I do not believe any of this. The Earth is flat.
Sarcasm for those who do not know me well
Sarcasm for those who do not know me well
Nytrunner
Pop lugs, not drugs
Did you forget to pump it up last night? Have you checked for leaks?
Winston
Lorenzo von Matterhorn
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I love that quote
.
dr wogz
Fly caster
and the only thing they fear, is sphere itself!
Winston
Lorenzo von Matterhorn
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Scientists now have evidence a large platinum-dense meteorite [asteroid] hit the earth 12,800 years ago
October 8, 2019
https://qz.com/africa/1723888/scientists-say-a-platinum-meteorite-hit-africa-12800-years-ago/
Just less than 13,000 years ago, the climate cooled for a short while in many parts of the world, especially in the northern hemisphere. We know this because of what has been found in ice cores drilled in Greenland, as well as from oceans around the world.
[snip]
The new information has been obtained from Wonderkrater, an archaeological site with peat deposits at a spring situated outside a small town to the north of Pretoria. In a sample of peat we have identified a platinum spike that could at least potentially be related to dust associated with a meteorite impact somewhere on earth 12,800 years ago.
The platinum spike at Wonderkrater is in marked contrast to almost constantly low (near-zero) concentrations of this element in adjacent levels. Subsequent to that platinum spike, pollen grains indicate a drop in temperature. These discoveries are entirely consistent with the Younger Dryas Impact Hypothesis.
Wonderkrater is the first site in Africa where a Younger Dryas platinum spike has been detected, supplementing evidence from southern Chile, in addition to platinum spikes at 28 sites in the northern hemisphere.
[snip]
A meteorite crater in Greenland
Very recently a large meteorite crater with a diameter of 31km was discovered in northern Greenland, beneath the ice of the Hiawatha glacier. It is not certain that it dates to the time of the Younger Dryas, but the crater rim is fresh, and ice older than 12,800 years is missing.
It seems possible (but is not yet certain) that this particular crater relates to the hypothesised meteorite that struck the earth at the time of the Younger Dryas, with global consequences.
The effects of a meteorite impact may potentially have contributed to extinctions in many regions of the world. There is no doubt that platinum spikes in North America coincide closely with the extinction of animals on a big scale about 12,800 years ago.
October 8, 2019
https://qz.com/africa/1723888/scientists-say-a-platinum-meteorite-hit-africa-12800-years-ago/
Just less than 13,000 years ago, the climate cooled for a short while in many parts of the world, especially in the northern hemisphere. We know this because of what has been found in ice cores drilled in Greenland, as well as from oceans around the world.
[snip]
The new information has been obtained from Wonderkrater, an archaeological site with peat deposits at a spring situated outside a small town to the north of Pretoria. In a sample of peat we have identified a platinum spike that could at least potentially be related to dust associated with a meteorite impact somewhere on earth 12,800 years ago.
The platinum spike at Wonderkrater is in marked contrast to almost constantly low (near-zero) concentrations of this element in adjacent levels. Subsequent to that platinum spike, pollen grains indicate a drop in temperature. These discoveries are entirely consistent with the Younger Dryas Impact Hypothesis.
Wonderkrater is the first site in Africa where a Younger Dryas platinum spike has been detected, supplementing evidence from southern Chile, in addition to platinum spikes at 28 sites in the northern hemisphere.
[snip]
A meteorite crater in Greenland
Very recently a large meteorite crater with a diameter of 31km was discovered in northern Greenland, beneath the ice of the Hiawatha glacier. It is not certain that it dates to the time of the Younger Dryas, but the crater rim is fresh, and ice older than 12,800 years is missing.
It seems possible (but is not yet certain) that this particular crater relates to the hypothesised meteorite that struck the earth at the time of the Younger Dryas, with global consequences.
The effects of a meteorite impact may potentially have contributed to extinctions in many regions of the world. There is no doubt that platinum spikes in North America coincide closely with the extinction of animals on a big scale about 12,800 years ago.
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