Loading...
“The [Younger Dryas Boundary] theory has reached zombie status,” said Professor Andrew Scott from the Department of Earth Sciences at Royal Holloway. “Whenever we are able to show flaws and think it is dead [!], it reappears with new, equally unsatisfactory, arguments.
- “Sniff,” January 30, 2013, Royal Holloway Press Release two weeks before the Harvard discovery.
Among other causes, the Younger Dryas impact hypothesis [4] is based on observations and is testable. A C-rich layer, exposed in many sites in North America and Europe at or near the YD boundary, is enriched in magnetic grains with Ir, magnetic microspherules, charcoal, soot, carbon spherules, glass-like carbon withnanodiamonds, and fullerenes with extraterrestrial. This has been interpreted as evidence for an impact or aerial blast at ~12,900 years ago. Subsequent studies both cast doubt on [5-12] and found new support for [13-14] the petrographic evidence. However, the invoked markers have never been supported by a geochemical impact signature such as a sharp increase in Ir or other PGE concentrations……..
……..Our results could be explained by the impact of an iron meteorite with low Ir and high Pt con-centrations like Sikhote-Alin (IIAB) or Grant (IIIAB); the former is a large crater-forming meteorite shower. If the Pt peak is caused by an iron meteorite impact, then the observed gradual ingrowth of the Pt concentration in ice over ~25 years requires lifting impactor’s material above the stratosphere and formation of a ring around the Earth. The decay of the Pt signal is consistent with ~5-years lifetime of the dust in the stratosphere. Such an impact could result in a global Pt anomaly. An anomalous 50 cm thick ice layer with 100 ppt Pt would require a sub-km-size iron meteorite to account for the Pt mass-balance.Concluding remark: The main conclusion of our study is the detection of an unusual event during the Bølling-Allerød- YD transition period that resulted in deposition of a large amount of Pt to the Greenland ice.The nature of the event remains uncertain, but our results clearly rule out an impact or airburst of a chondritic bolide. If an impact was involved, the impactor had a very unusual composition deriving froma highly fractionated portion of a proto-planetary core.
Harvard Researchers Discover Evidence for Major ET Impact at Younger Dryas Boundary by George Howard
This does seem contradictory to the evidence of Firestone et al who found an increased iridium signal in stratigraphy attributed to the the YD boundary, given that the hypothesised bolide in this study is low in iridium. It seems strange that there should be a high deposition of iridium over land and little accumulation of it in ice cores if the bolide was iridium rich, and even stranger if it was iridium poor.
Jonny,
metal condensation cores of comets, my lay insight, are needed for slow gravitational accumulation of ices and dust. If so, variant, inhomogeneous densities likely, especially if distinct pre-cometary parts combined, & would explain pt in Greenland, ir over land.
Why do you say “hypothesised bolide in this study is low in iridium” if it was most likely a comet or comet frag?
The following passage struck me as interesting:
1. A “huge” meteor shower – What does this mean, in general? Does it mean that the impactors were huge? That there were very many of them? Evidently those that impacted are the basis of this adjective, “huge,” since ones that didn’t impact would have left no trace.
2. That it was at ~10,000 years ago – Why do people confuse 10,000 years ago with 12,900 years ago, like they were two week apart? 2,900 years is essentially 50% longer than the time since J.C. That is a lot of “wow” (fudge) in their numbers.
3. If it was at the time of the YDB, it shows that at that same time there was a multiple impact, of some sort.
4. Halley and Hale-Bopp – didn’t they show that comets are not just ‘dirty iceballs’? As I understand it (please correct me if I am wrong about this), the distinction between comets and meteors/asteroids has become muddied (no pun intended). It seems that we are a long way from knowing what mixtures of ice and rock and iron are out there. If so, the West York “iron” meteor shower could have been a broken up comet with at least some iron and some other materials.
5. Are impactors assumed to be heterogeneous? If a meteor had broken up and was not heterogeneous, the fracturing could easily have been between the different materials aggregated together. (I assume aggregated because they historically seem to me to have been somewhat friable.) What better place to fracture than at the discontinuities?
6. If not heterogeneous, different fragments may have considerably different constituents.
7. On another front, some of us have concluded that the YD impact was a multiple air burst. A multiple air burst is different from a meteor shower in what ways? In materials, certainly. In any other ways? Yes – a comet break-up is more likely than a meteor break-up to be friable enough to air burst. If meteors can break up, and if the comet S-L/9 broke up, then obviously both meteors and comets DO break up.
Is there anything that prevents some of the fragments of a break-up from impacting while other parts air burst? That we have not yet seen it – is that enough reason to argue that it doesn’t happen? If ti happens once in 20kya or 30 kya, we would only get one shot at seeing it happen (if that). And if we try to recognize it having happened 10kya or 13kya or 20kya, what would we expect to see?
From all that off-the-cuff reasoning, it seems the West York iron meteor shower may or may not be connected with the YD, both in time and in its break-up. While doubtful in time, and even more doubtful in constituents, are we comfortable saying it is impossible?
I hate arguing from negatives, which cannot be proven or falsified. But I would lean toward putting this aspect of this paper in the back of my mind. More evidence may come down the line. Till then, I will say it is doubtful but that certain aspects suggest that knowing about it may prove useful later on.
Hermann -
In your first part, it seems we picked up on the same (in)homogeneous thing.
But I got my words backward! Dammit!
5 and 6 should read:
5. Are impactors assumed to be homogeneous? If a meteor had broken up and was not homogeneous, the fracturing could easily have been between the different materials aggregated together. (I assume aggregated because they historically seem to me to have been somewhat friable.) What better place to fracture than at the discontinuities?
6. If not homogeneous, different fragments may have considerably different constituents.”
I don’t know where my brain was with that word. Sorry, folks.
But it is also not impossible that it was pt in Greenland, ir over land, and part missed. The Earth, unlike Jupiter, may not have enough of a gravity well to ensure that all fragments would impact.
Addressing Jonny’s (and the paper’s) point:
“It seems strange that there should be a high deposition of iridium over land and little accumulation of it in ice cores if the bolide was iridium rich, and even stranger if it was iridium poor.”
I agree in principle. It does seem strange.
1. The evidence IS there that the meteor shower was Ir rich, and at about the same time, the ice cores show extremely Ir poor..
So, what kind of scenario can possibly explain that incongruity?
A. They happened at different times. 10 kya is not 12.9 kya.
B. They happened at the same time, but the fragments were different in materials. This could be possible (even if it would certainly be “strange”), based somewhat on my #7 above.
The more likely of these is A. But admitting that two very large impactors arrived within 2.9 kya of each other, or maybe even simultaneously – either one would be a problem for those who adhere to the “rare impact” viewpoint.
It seems that, one way or another, some viewpoints need to adjust/flex.
Hi Steve, kiddo,
don’t worry about that!
Q1 = Heterogeneous?
Q2 = Homogeneous?
Those two Q’s are logically equivalent,
A1 = not A2.
So, why do you think Jonny thinks it was low on ir? Is that in one of the papers by the Firestone team?
BTW, GUS* synched our brains, what? Even I first chose heterogeneous, then took homogeneous because people would know it better, can you believe that?
– - –
(*) Great Universe Spirit
Oh, come on, Jonny. Colonel Mustard with the Flat Iron, Colonel Mustard with the Chopping Block…..there is a bloody body.
What we have here are nervous servants walking around the corpse telling us the old man just tipped over with his toddy. Give me a break.
Steve, in regards to your question concerning bolide breakups, your question is incomplete.
If we are going to draw a line to distinguish between asteroids, and comets, then that line should be related to the amount of volatiles in the object. Or more simply: Is it an icy body or not? So if it’s a fairly solid chunk with no ices, or volatiles to out-gas in the inner solar system, it’s no comet. This brings us to recognizing that there may be many different breakup mechanisms to take into account, depending on the compositional nature of the object, and it’s structural integrity.
For example, the breakup of comet Shoemaker Levy was caused by tidal forces from Jupiter’s intense gravity field as it made it’s first close pass of the gas giant before returning to impact. There the breakup mechanism stretched the fragments out into a long stream that came back to impact one right after the other. But we don’t have to look very hard to find a completely different, and probably far more common breakup mechanism of an icy body.
Just take a look at Comets Linear, or SW-3. In both cases we see comets that broke up without any gravitational influence from a planetary body. It’s as if the ices holding them together lost integrity after sublimating away in the inner solar system, and they just came unglued like the wings of Icarus.
Bottom line: The breakup of an icy body can happen at any time. It doesn’t have to plow into an atmosphere first. Nor does it need to make a close pass of a planet, and be torn apart by tidal forces and stretched out into a string.
There is no logical reason to assume that a meteor shower, or large impact storm, is never the result of a large cloud of cometery fragments such as either of those two examples impacting soon after the complete breakup of a large comet. Yet the only pre-impact breakup mechanism folks seem to be able to consider is the silly idea that we only need to be concerned with single lone bolides that arrive one at a time, and don’t begin to breakup until they get here.
Herman,
It doesnt matter whether the iridium was in a differentiated core, or homogeneously mixed through-out the body upon impacting and vaporising, the debris becomes mixed in the atmosphere, and so will be deposited upon the ice caps, so if there was an iridium rich part that fell over the continent, then we should still see enhanced iridium in the ice cores. Indeed, if the scenario suggested is correct, and a ring of debris was formed around the earth, and coupled with a mean atmospheric residency time of 5 years, then we should expect an iridium excess in the ice cores if there was increased iridium on any part of the impactor. So in an extreme case, even if the bolide was made up of two halves, one iridium rich, and one platinum rich, with the iridium impacting over land and platinum elsewhere, we would still expect iridium enrichment in the ice cores.
The ice core chemistry does not tell us that an impact occurred over Greenland, merely that there was an impact somewhere.
I also say hypothesised bolide, since that is what it is, a hypothesised impact event of an platinum rich iron meteorite, since we have no conclusive proof that it was an iron rich impactor, or indeed if it is an impact at all. We have data that could be interpreted as an impact, and the authors have hypothesised it was due to a particular composition of impactor. They also note another hypothesis that the platinum could be induced by a super-volcano. Thus having two hypothesis we can now look for other physical evidence to support or falsify either hypothesis.
Steve,
It was noted that while the cape york meteorites could be dated to 10,000 years ago, there was equal platinum to iridium in them, which does not match the Pt/ir ratio in the ice cores, suggesting that they are different bodies, and likely not contemporary with each other.
Why this is considered a huge meteor shower is because of the large fragments of meteorites that have been found, the largest being 31 tonnes.
Undoubtedly the Cape York shower occurred at a different time to the YD boundary. Its inclusion in the paper would have been to discount a local contamination of the ice cores from this shower, since although the ice-cores can be dated with a degree of precision, such precision may be lacking in the dating of the Cape York meteors, thus some could potentially argue that the Pt anomaly was caused by the cape York meteor. By comparing the Pt/Ir content of these meteorites to the Pt/ir ratio in the ice core discounts this meteorite being the cause of the platinum anomaly.
Hermann,
I say that it was low in iridium because that’s what the ice-core data shows. If you look at the graph in figure 1b of the paper under discussion, you can see that there is no iridium anomaly associated with the platinum anomaly. Indeed, the iridium concentration at teh platinum anomaly is pretty much equivalent to background across the 300 years investigated. Therefore, as the authors conclude, if it was an impact event, then it would have to be low in iridium not to leave an iridium signal. Compare this to the 2007 Firestone et al paper in which they show in their stratigraphy analysis a marked excess of iridium at the YD boundary.
George,
No one is dancing around any body here, and all this paper does is confuse the identification of any body, as well as whether it was murdered or not. Indeed it goes so far as supplying a second dead body.
You posted a paper that on the surface seemingly supports Firestone et al, but when you look at the actual “forensic” evidence there is a glaring disparity in iridium concentrations between the two studies. Why does Firestone et al find an iridium anomaly at the YD boundary, but seemingly contemporaneous ice cores do not show such an anomaly?
The problem is this. Looking at the Harvard study alone, we can interpret this as an impact event. Looking at the Firestone data, it could be interpreted as an impact event. But looking at them together with the ice core chemistry, they cannot be both the same event due to the iridium evidence. Indeed, even if the Harvard data is not extraterrestrial in origin, it still leaves the problem of a lack of corroboration of enhanced iridium in the ice cores that purportedly date the same epoch as Firestone et al’s stratigraphy.
Therefore this paper is no help in reinforcing the YD impact hypothesis, and could in fact weaken it. Also, the Harvard study does resort to a form of special pleading. In order to explain the platinum excess, they propose an impact event, but in order to explain it as an impactor they must suggest that it is a special type of impactor from a fractionated proto-planetary core to explain lack of iridium. It doesnt mean that it is wrong, but it is a stretch.
Dennis,
There are different causes of comet fragmentation. These are, impact fragmentation, tidal disruption, thermal stresses, and spin up. The first three are self explanitory, the first occuring from an object hitting the comet with enough force to disrupt it. The second we observed with SL-9, and the third is the what we all assume is happening, but all three can give rise to the forth fragmentation mechanism.
As a rotating comet looses mass though jetting and gas drag on dust particles, it’s spin rate will increase. The spin rate increases in order to conserve its angular momentum. As the angular velocity increases, so to does the centrifugal acceleration until the weak internal forces can no longer balance the centrifugal acceleration, at which point the comet comes apart.
Thanks Jonny,
That’s exactly my point. And if we read Professor Napier’s Paleolithic extinctions, and the Taurid Complex describing the progressive breakup of a very large body then finding evidince of multiple major impacts over a period of centuries is to be expected.
I would be surprise if there was only evidence of one.
[...] the marvelous platinum result, I’m baffled! An iron meteorite is unlikely to fragment Earth-wide, and the lechatelierite [...]
[...] high Fe/Ni ratios, pdf’s, shock melted quartz, high 10 Be/9 Be ratios and occasional presence of platinum metals. Controversy over the impact, the so-called Black Mat enigma, and its relation to the Younger Dryas [...]
With all of the discussion about the possibility of multiple relatively current impacts I am a bit disappointed that more effort hasn’t been made with regard to identifying where these impacts may have occurred. I would also suggest that there have been numerous research expeditions around the globe that would facilitate the start of this study. For example ocean sediment depths.
I think it would be safe to assume that the odds are in favor of the majority of impacts striking in the oceans of the world and that where ever this has occurred all of the sediment in the strike zone would be blown away.
In my brief efforts to correlate this kind of research (there are volumes of sediment studies at Scripts Institute in San Diego) along these lines I found that one of the places where there is the least amount of ocean sediment is off of the west coast of South America. I believe there is also a substantial amount of other evidence that would suggest that a comet impact occurred there around 500 BC. (For instance: Darwin noted recent coastal uplifts in his studies in South America, recent digs on the Peruvian coast that date to this time where complete cities were buried under 50 feet of sediment)
I am sure that most of you are aware of the Yucatan impact (Chicxulub crater) which was discovered by a geologist working for one of the oil companies who was looking at gravitational anomalies. This kind of research (by oil companies) has also been conducted all over the world and as such could be requested – in regards to where likely impact zones could be located.
One thing that is missing though is an ACCURATE computer model for what actually would happen if a larger comet or asteroid hit the planet in the ocean. Although there are several out there, what is not included is how the crust would flex in such situations. In most cases it seems to be assumed that a comet would penetrate the crust in the same way that an solid object would. I would suggest that this is not the case. Of course this would be influenced greatly by the angle of impact as well. This could make for an interesting discussion:)
I believe there is some evidence of a sudden warming in the Greenland samples at around 5500 years ago. Whether there are physical deposits in the ice or not would probably depend greatly upon where the impact occurred relative to Greenland and the direction of the incoming object.
Although I am sure my conclusions are probably going to passed off as novice musing here they are anyway:
500 BC a comet impact near the equator around 500 miles southwest of Ecuador.
3500 BC a comet impact in the Indian ocean south of Bengal about 1000 miles
7500 BC an asteroid impact in the Atlantic around 1000 miles or less west of Spain.
10,000 BC an asteroid impact in the north Pacific in the area of the Aleutian Islands.
[...] This is certainly appropriate given the The Bos’ paper, by their own admission, was designed to be a definitive critique that should halt research into the YDB. Common courtesy — and scientific method — would demand The Bos take a deep breath in [...]
Excellent comment, Rahn. Missed that.
Actually, that would pretty much be my short list too, Rahn — with another on the ice in Canada.
Rahn –
I missed your comment on Feb 28. It’s a good one.
I might want to add Ed’s 536 AD jobby, too.
Now note that Rahns’ list, with the YDB and 536 AD, becomes:
12.9 kya
12.0 kya (delta 0.9 kya)
9.5 kya (delta 2.5 kya)
5.5 kya (delta 4.0 kya)
2.5 kya (delta 3.0 kya)
1.7 kya (delta 0.8 kya)
Mean delta = 2.24 kya – with a range of 0.8 to 4.0. Median is 2.5 kya.
536 + mean delta = 3076 AD
536 + least delta = 1336 AD
536 + most delta = 4536 AD
What could this mean? That, more or less, we should not be surprised if an impacting object showed up tomorrow. But it is definitely time to start taking it seriously. We are on the clock.
If we exclude 536 AD, then we have a mean delta of 2.6 kya.
500 BC + least delta = 1436 AD
500 BC + mean delta = 2100 AD
500 BC + most delta = 4500 AD
Again, of course, we are on the clock. Who the hell knows when?
But I am one who thinks that not only do we have the technology to go deal with these things, but that we can go out now and start learning what to do and how to do it – and maybe even make a profit on it – and lean from the NEOs how to keep going and get out ot the asteroid belt, where big profits might be made. There are ways that exist, even now, and people pushing the envelope. Unless the hit comes in the next 50 years, we should have the situation well in hand.
But I really don’t think it will be NASA doing it. NASA’s little “Bring home a 5 ton NEO” is almost as stupid as doing nothing. Knowing them, they will bring it down from Earth orbit – to (they think) great acclaim and for show and tell – and change the environment of the object so that gases can’t be studied properly. “Look, Ma, it followed me home!” Can I keep it?”
Chebarkul has motivated more people. Fortunately, some of those people are not NASA. UN-fortunately, WE are stuck with NASA. As long as Morrison is there, the USA effort will be for the purpose of getting funding – and for him not being the director who presided over the demise of NASA. Also, unfortunately, NASA will give the job after Morrison to some numb nuts like Bos, someone who is anti-NEO protection (unless it means he can pose for photon bites).
Alright I’m breaking radio silence to soap box some more for basic mechanics and especially for shallow angle impacts. Anyone tired of those topics can skip this post.
Careful Jonny
in your February 15, 2013 at 6:39 am post your wrote:
“…There are different causes of comet fragmentation. These are, impact fragmentation, tidal disruption, thermal stresses, and spin up. The first three are self explanitory, the first occuring from an object hitting the comet with enough force to disrupt it. The second we observed with SL-9, and the third is the what we all assume is happening, but all three can give rise to the forth fragmentation mechanism.
As a rotating comet looses mass though jetting and gas drag on dust particles, it’s spin rate will increase. The spin rate increases in order to conserve its angular momentum…”
Actually…
This is only true for a conservative system which is acted upon by no externally applied unbalanced forces. Each of the differential bits of mass which leave the bolide, however, impart their own momentum upon the bolide during departure from that object, and said momentum may (usually does) include some angular component or torque impulse unto the bolide. For an irregular bolide shape or irregular departure direction other than purely radial, most of the mass that leaves will impart some torque, however minor.
When all of these angular impulses are integrated over the entire mass depleted (fraction of a planet), and over the duration of depletion (billions of years), the results could be almost anything. Any assumption of pure conservation of angular momentum in this scenario is out the window.
Out the window.
Conservation of angular momentum (or linear momentum for that matter) requires the system not to be acted on by any external unbalanced force. So to determine final spin rate after depletion, one would have to draw a control volume around the entire mass, INCLUDING all the mass of escaped or depleted volatiles, or one would have to define the angular impulse imparted by any and all differential mass elements leaving the bolide and sum those to find the result.
It is, by definition, another statement of the rocket problem. You can’t just say F=MA when M is variable over time (because you are burning fuel or outgassing volatiles, pardon my vulgarity). And this is true for both linear or angular systems, just fill in the dimension of choice, length or angle.
Also, from Feb 15 at 5:20 am:
“…if the scenario suggested is correct, and a ring of debris was formed around the earth,…”
Shallow angle impact is one possible case to allow this sort of thing. Much of the mass of the impacting bolide may depart the impact site at, near or even slightly faster (!) than the approach velocity (See “Fate of the Projectile” hydrocode paper). A smaller percentage of the mass will have distributed departure velocity down to something much less than that of approach.
And distributed direction of departure! This is critically important!
Now picture a larger bolide which has the punch to spray most of its mass back out of the atmosphere after a shallow angle impact. Take your pick of which range within that departure velocity distribution may stay captured in Earth/Moon orbit for a few years.
This is why shallow angle impacts are so important.
In one way they are far more complex than a steep angle strike, due to the complexity of post-impact momentum distribution. I am baffled as to the lack of further research in this area, when CLEARLY the initial studies point to critical questions and results that may apply very well to the problematic longer term time scales of climate effects after impact.
Not to mention how we don’t know what a shallow angle strike scar wold look like if the event happened on a mile(s) thick ice sheet. Or what would happen if a shallow angle strike on the moon were to launch a plume with such a distribution of momentum (remember the distribution of the pulverized bolide spray is both through a range of velocities and a range of azimuth and elevations angles.) PBS. Pulverized Bolide Spray. Almost as good as Bolide Ignimbrite.
The shallow angle strike is arguably far more complex than the steep angle strike that absorbs all the momentum to initiate cratering. In the shallow angle case, the bolide momentum becomes diffused over a range of angles and speeds, to be released as such back into the orbital mechanical environment. The bolide momentum and its composition become more complex by definition.
Instead of simply being absorbed by the impact and starting a subsequent cratering process as in a steep angle strike, the shallow angle strike becomes convoluted into a more complex set of treacherous hoodlums, all heading in different directions with different astro-mechanical sizes and energies. Its one thug that gets transformed into an entire gang, all with bad attitudes.
Think about it.
Sure, maybe it has nothing to do with anything that has ever happened to Earth before. And maybe there is no water on the Moon either.
Oh, yeah, water has been discovered on the Moon, and its in quantities that NASA scientists believe must be replenished to explain the levels. Really? Yes, really.
Foolish not to study shallow angle impact science more closely, especially given the profoundly serious implications for our puny species within the greater, more violent local environment in which we have evolved, not to mention to offer causal alternatives for post impact climate effects over time scales too long to be explained even by the most complex and advanced climate models to date.
Think about it.
Look both up and down.
TH
Fresh Cluster of Impact Craters on Mars
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA16928
TH
At Space Daily:
“Borneo stalagmites provide new view of abrupt climate events over 100,000 years”
http://www.spacedaily.com/reports/Borneo_stalagmites_provide_new_view_of_abrupt_climate_events_over_100000_years_999.html
I wonder how well they can correlate from the YDLB epoch
Every new record offers more potential clues….
TH
On 6/13/2013 6:14 PM, Steve Garcia wrote:
TH -
From the article:
My first take on this was, “How could D-O evens register in Borneo, where there is no winter, but only rainy season/dry season?” But then I assumed that they must be reading the stalactite rings like tree rings – rainy season creating much more flow and deposition.
There are THREE such “events” in the Quaternary — D-O events (in the Pleistocene), Heinrich events (Pleistocene and Holocene), and Bond events (in the Holocene).
The Bond events and D-O events MAY be the same things, merely extended into the Holocene, since BOTH have periods of 1,470 years on average.
From Wikipedia:
From Wikipedia:
From Wikipedia:
Let me first say that the INTERPETATION of any of these as “ice rafting” is not necessarily the facts of the matter, but may only be a Gradualist crowbar, trying to squeeze what might be catastrophic events into the Uniformitarian model. (After all, the 18O levels in the GISO/GRIP ice cores spike at those points very extremely, FAR beyond anything seen in the later Holocene.) IMHO, it is a speculation/hypothesis that is accepted by everyone simply because someone came up with a gradualist “explanation” that everyone has agreed to accept and run with. It may be true, and it may not be, but no one so far has really suggested any doubt about it. I do, though.
If even ONE of the events is actually tied to an impact, all bets are off. And our YDB is that exact possibility.
And what would that suggest, if the connection comes to pass? Obviously this: That the ice rafting didn’t happen at all, and that the events were had cosmic causes.
Outlandish?
Here, also from Wiki:
This says that the regularity can, so far, not be tied to Earth system (meaning terrestrial) causes, because they would never be as regular as D-O events, even for just those last five cycles. They also cannot be tied to any orbital periodicities.
The former is very important, because Heinrich events are closely tied to D-O events, and their histories overlap for a long period of time. But Heinrich events are tied to ice rafting. Yet Earth system regularity to the degree of D-O events is pretty much ruled out – and that SHOULD include ice rafting. Who in their right mind would suggest that ice dams fail at 1,470 year intervals almost like clockwork?
Nobody.
And if the lunar 1,800-year cycle is ruled out, too, then what else is left? No more orbital processes have come to the fore, and Earth system processes cannont be that regular. I repeat: what else?
So can we speculate on impacts? Well, the YD onset is considered to be one of the Bond events. That should make the current impact studies on the YDB also possibly applicable to the other Bond events. And since Bond events and D-O events are tied together, and since the Heinrich events are also somewhat tied to the D-O events, why is no one yet inquiring into this possible connection? Though it can only be speculation right now, personally, that is where my money is being bet. And if that turns out to be a real posssibility, then the ice rafting is more climate speculation gone wrong.
Comets are a non-Earth system reality. Comets are regular in their orbits, often within that 2% or 12% mentioned above. Once fragmented, their matter stream is in place just waiting for the Earth to lumber by. We have the meteor showers every year from certain comets having been broken up. It does not seem impossible that meteor showers at frequencies of 1,470 years could exist.
From Wiki again:
FWIW: Doing a quick spreadsheet on the YD onset and the 1470 year cycle, I don’t agree with that timing at all. The Little Ice Age began about 1400 CE. The 1470 cycle from 12,800 ya puts a Bond event at 960 AD and 2430 AD. That seems to me to be about 500 years out of whack. The 8.2 kya event also doesn’t fit with the YDB.
However, the 8.2 kya and the 536 AD fit very nicely. And they both fit very nicely to NOW. That might suggest that a D-O/Bond event is due NOW.
This might give us a handle on how urgent it is to do something NOW in terms of planning a proving out a deflection program. And, like Ed says, it should take precedence over any Mars efforts.
Oops! That says I posted this twice. Sorry! I had thought I’d only saved the comment (mostly done yesterday) but not sumbitted.
George, can you delete the first of the two?
Apologies.
Steve,
Yeah that 1470 yr cycle combined with a 12.8 ka YD date gives us about 430 yrs of breathing space…
until you throw in the relatively huge +/- 500 yr variation, in which case all bets are off for any breathing space at all.
I wonder if Napier has figured any of this out. He is a good authority on the kinds of orbital perturbation that can spell hit or miss in these situations. I’ve never seen any short period numbers in his work though, not like 1.47 ka at least.
Fishy fishy fishy….
TH
FWIW, if you can indulge me here, I’ve begun to look into the Heinrich events, D-O events, and Bond events a bit more. I had found speculation presented as assertion, but had found nothing in the literature that cast doubt on the ice rafting meme. But I just found this:
. . . “seems to”. . . “suggests”. . . “a [mystery] stimulus in the European sector”. . . the latter is also a crowbar, trying to force a fit with Gradualism.
On a topic that overall “seems to” be a settled “fact”, and that other deposits were occurring 1500 years earlier does one thing in my head:
It makes me wonder how little all this “ice rafting” is based upon and how much upon Gradualistic crowbarring, as I keep saying. (I am not stopping with this…)
But the chemistry match with DUST in Greenland argues 100% against ice rafting and FOR an impact event, as the abstract argues (but then they have to keep on avoiding catastrophic possibilities). What is matching DUST doing, being deposited on TOP of the Greenland ice sheet if it came from UNDER icebergs? (See the silly cartoonish depiction at http://tiny.cc/0vcqyw)
One of my aims is to see what the evidence is for their assertion that the debris fields from “Heinrich fields” is actually “continental” as is asserted. Even if it CAME FROM continents, it does not necessarily rule out impact, since most of ejecta is from the target surface. The Ice raft hypothesis is only a gradualist interpretation so far as I can tell so far, and IT should be challenged – and this paper is the first I’ve seen that does that.
Perhaps comparing the layers in Greenland with the ones in the YDB research would show a temporal match. http://cosmictusk.com/ydb-press-release-scientists-discover-nanodiamonds-in-greenland-ice/
So, no conclusions possible here, but finding reason to accept that the impact scenario I am wondering about is actually feasible. A door is open, at least in my own mind. And within our OWN hypothesis, if an academic someone can make a tie to this, it IS one area that will need to be addressed at some point. Whatever the final reality, it will have to tie in well enough with all relevant tangencies.
TH was onto this, too, BTW, so thanks, TH!
Steve –
You cold try googling on the authors’ names for more information on their work. After that you could try contacting them personally byu e-mail for copies of their papers.
The simlutaneous dust loading would appear to rule out solar variability as the cause. On the ohter hand, dust is also produced by volcanoes, and the possibiolity of co-incident timing can not be ruled out without esamining each of the dust loads further in much greater depth, as much as possible.
As far as the timing goes, you may want to look at the orbital mechanics of Comet 21P Giacobini-Zimmer.
Corrected copy:
Steve –
You could try googling on the authors’ names for more information on their work. After that you could try contacting them personally by e-mail for copies of their papers.
The simlutaneous dust loading would appear to rule out solar variability as the cause of the rafting. On the other hand, dust is also produced by volcanoes, and the possibiolity of co-incident timing can not be ruled out without examining each of the dust loads further in much greater depth, as much depth as possible.
As far as the timing goes, you may want to look at the orbital mechanics of Comet 21P Giacobini-Zimmer.
In reading on the Bond/D-O/Heinrich events I am amazed that a hypothesis is so readily accepted and presented as fact. In almost every sentence I can hear the self-brainwashing and great effort to fit in with their peers. As long as they do not consider anything cataclysmic, they have to apply the gradulaist thought processes at every turn, even when the thing gets more and more and more complicated. And why does it get more complicated? Because they aren’t able to correctly predict anything new, and new stuff comes up and doesn’t fit. If it doesn’t fit, they must not acquit, but throw it out and start over again. But they won’t. Because when it does not fit, they gerrymander the whole thinking about it again, twisting it to try to include the new stuff.
They all KNOW that earth processes are not repeatable within 2% on an oceanic scale, but they pretend like, “Well, there must be something in it that we don’t understand yet.”
But hoping for “something” to make everything fit – that isn’t science. I’ve said that phrase and heard it so much in the last ten years, but sometimes it’s true.
If the big picture idea – like the YDB or the Heinrich events – is true, then the scientists involved should be able to predict things that then come true. A true hypothesis IMPLIES things, and those implied things should be somewhat readily seen.
… One thing I found today was that an area WSW of England and SSW of Iceland is called the IRB – the Ice Raft Belt. It isn’t even in the zone of icebergs right now. See http://geology.gsapubs.org/content/28/2/123/F1.large.jpg.
The thing that struck me was that the is in the same exact place as the Gulf Stream. See http://upload.wikimedia.org/wikipedia/commons/e/e2/Golfstream.jpg (no idea why it is spelled that way)
So far I haven’t seen anyone who has ruled out the Gulf Stream bringing the debris and depositing it into the Pleistocene sediments – much of which (but not all) is actually small enough to be carried by a good current.
One of the things that the YDB implies, btw, is that materials WILL be ejected and be carried a long way – including the ocean. If there are markers across the Atlantic, there are markers IN the Atlantic. And perhaps the very cores that underlie the Heinrich “ice rafting” hypothesis have within them the same markers as are in Belgium, Germany, the Netherlands, and Syria. I predict that they will indeed be there, right alongside the micrometer-sized and mm-sized “continental rocks”.
BTW, I was VERY unimpressed when I found out that most of the “strewn rock fields” are comprised of mostly such small dust particles. They DO include some rocks called dropstones, but the explanation for those is pretty weak – but consistent with Gradualism. They can really only say that the rocks (which in a way are a lot like erratics) came down vertically to rest on the bottom. The connections with icebergs is all speculation that fits the Gradualist meme, so it is readily accepted and repeated – ad nauseum.
Boy, they can get away with any weak presentation or argument, as long as it isn’t catastrophic. The double standard is palpable. The YDB has to jump through hoops and run the gauntlet, but he ice rafting got a free pass. It fits gradualism? Then FINE, put it in!
Personally I think the ice rafting, as the cause of the evidence called the Heinrich events, Bond events and D-O events, is a house of cards at this point. (The D-O actually only seems to show up in Antarctica ice cores, BTW so far, not in the N Atlantic sediments.)
Argument 1: NO terrestrial forcings known to man can create the HUGE swings in 18O and temperatures seen in the pre-Holocene Pleistocene. They “suggest” and “offer” and “propose” and speculate various mechanisms, all over the place, and they know that nothing they are proposing is sufficient. And no sooner is one of the suggestions out there but someone else shoots it down, for good reasons. But those others have no solutions, either. And it won’t. The only force big enough does not exist in Gradulaism. And that force is out there in the shooting gallery known as the Near Earth region – comets and asteroids.
Argument 2: If those fluctuating events are shown to be close in time to the YDB at 12,800 ya AND a huge swing in climate occurred at THAT SAME TIME, then it only makes sense that whatever caused one of that magnitude very likely caused the others, as well.
Argument 3: One of the biggest reasons they fight the YDB so hard is because so much prior work will have to go into the round file. From every point except science itself, they are right to fight it. They certainly don’t want their careers to go down the drain. There would simply be too big of a change that will have to happen in academia. They have to fight it. Entire careers may have been wrong, and science be damned, they aren’t going to let their careers go down without a fight. (But who remembers the names of the cabrónes who stopped Galileo, or Copernicus, or Darwin? Or even Wegener?)
Argument 4: Right now it seems like the closest historical parallel to the YDB is Wegener’s moving continents and plate tectonics. The thing that preceded Wegener’s hypothesis was so silly they don’t even talk about it anymore. (At least physicists have the ether and will talk about it!) Wegener’s ideas overthrew – for good reason – the shrinking, wrinkling Earth. The YDB threatens just as big of a thunderclap, but in a much shorter time period. This one is even bigger than Alvarez’s dinosaur killer. That was 65 million years ago, and everyone yawned and said, “So what? Like that makes a difference to us now?” (even though, yes, it did…)
Guys, if the N Atlantic cores show impact markers, this whole thing will get a whole lot bigger – and nastier. The cores still exist. I wonder if they even have a black mat?
I used to see those D-O 18O graphs on the climate change blogs I frequent, and I wondered about them, but thought mostly, “WOW! The climate sure changed a lot, back and forth and REALLY to the extreme!”
Then someone in a comment on WattsUpWithThat.com ridvculed the YD impact idea, saying that if we thought a comet caused the Yuonger Dryas, then what about those other sharp declines and inclines, back through 100,000 years or so? I thought he was insulting us, but really his point was valid.
If the YD onset was from an impact then we can’t NOT look at those other dives in the climate. What caused them?
The reason the YD stadial is studied so much isn’t because it nosedived, though that is most people’s focus. The thing that makes the YD stand out and be studied is that it lasted as long as Islam has lasted – 1300 years. The YD end was JUST LIKE THE OTHERS. But WHAT forestalled its recovery? And once established as a cold regime, WHAT made it recover so fast, like the others?
If we answer one, we answer all of it.
Steve –
The Younger Dryas is related to the drainage of a glacial melt.
The Holocene Start Impact Event is related to the beginning of that particular glacial melt.
They are different events separated by a large number of years.
Please stop confusing the two.
PS – I “believe” in ice rafting. I am interested in its cause and its periodicity.
Ed -
That drainage of the Laurentide sheet as the CAUSE of the Younger Dryas is commonly asserted. But they point at that as not only the cause, but as tied to the Oceanic Conveyor, which I argue is not proper physics. Read Rodney Chilton’s book to see how many holes that drainage idea has in it. The timing of the ice dam break is wrong; the Great Lakes were not freed up in time, plus the scablands-like great flood evidence just ain’t there. The latest pathetic idea (and it IS pathetic) is that the thing drained out the MacKenzie River up in the far northwest of the Yukon. How they expect THAT to affect anything in the N Atlantic boggles the mind. But they are clinging to that idea, even though it won’t hold water. All puns intended.
Be aware that the entire IDEA of that melt surge at that time is simply speculation. Read Rodney’s book. The backed up water behind the ice dam? It’s a pipe dream. But they NEED that fresh water in the N Atlantic because the oceanic conveyor idea is the centerpiece of their rapid climate change thing. Remember: They don’t accept the impact, so they have to crowbar something in as a cause. They have the oceanic conveyor shutdown, but that is a crock. Water sinking from convection is FAR to small a force (and is omni-directional) has NO capacity to selectively draw water from the the lower end of the Gulf Stream. It’s the stupidest idea since global warming.
No less a scientist than Carl Wunsch has this to say about that:
I am not stopping you from “believing in” ice rafting. It happens, yes. Rocks and dust are ground into glaciers and are carried into the ocean on icebergs. There is no denying that.
But does it happen as a significant part of the HUGE variations in temperatures seen in the record? Like 20 times as great as we’ve had since 1900 – only in the other direction?
If the ice rafting happened at the same time (see just below) as the YD onset, then as an impact man you seem to be saying that TWO mechanisms put debris into the ocean at that same time – icebergs and the YD impact. That is a big coincidence.
As to the HSIE and the glacial drainage being at the same time or not:
Wiki: “Some (Broecker 1994, Bond & Lotti 1995) identify the Younger Dryas event as a Heinrich event, which would make it H0.”
Broecker is THE guy who invented the ice dam idea and the oceanic conveyor. HE thinks the two are the same and NOT disconnected in time. He ALSO has backed off on the Laurentide draining via the St Lawrence.
And his THC and its potential to shut down – that is EXACTLY the thing Wunsch above is talking about.
So, basically I respect Broecker for admitting the drainage things is a bust (unless he can show how fresh water up in the Yukon can not dilute before it makes it past Baffin Island and that archipelago). But Wunsch calls Broecker’s THC shutdown idea “scientifically impossible or so unlikely as to threaten our credibility as a scientific discipline.” OUCH!
So BOTH of Broecker’s hypotheses are untenable.
I am just waiting for him to agree with Wunsch and tell the world the THC shutdown is wrong, too.
Steve –
Once again, as the HSIE precedes the YD by many years, it would help if you would use the correct terminology.
I have read Rod’s book.
I am interested in the data, not the climate models, nor your thoughts on either them or global warming.
In particular, I am interested in the data on the Pacific Current ca. 10,875 BCE.
That inclues any data on possibe northern drainages occuring shortly afterwards.
The melt and the drainages are geological facts, though still poorly understood and dated.
If you compare the Pleistocene-Holocene transition with earlier glacial cycles, you will notice that the most recent transition is clipped, has a flat top well below the earlier maxima.
Okay, Ed -
You lost me there. You seem to be keeping a secret. Explain please what the difference between your HSIE and the YD onset are. If they are different it is new to me. Since you are the only one on the entire internet that uses the term HSIE (I looked), maybe you need to specify how you are using the term.
Every source I have read states that the onset of the YD is the start of the Holocene. Are you keeping a secret from the rest of us?
No secret there.
Take a look at the DATES, Steve. The drainages come well after the impact event.
Aside from that, temeperture proxies for Europe have little to do with the temperature proxies for the glacial areas of North America, or for those of the PACIFIC CURRENT.
The artic drainages to the Pacific Current are important, particularly any as regards the MacKenzie River, as well as other possible routes.
Steve, I know you are just beginning to learn about impact processes. Forget what others wrote, and take a look at the raw data on the DATES.
Ed -
The drainages – I agree, except that the drainage never happened like they wanted it to. that is what Broecker had to admit, that the drainage couldn’t have happened when he needed it to happen. But then nobody could find the evidence of the drainage, either. THAT is why they are considering the MacKenzie River outlet: It never DID drain down the St Lawrence like they thought. Yes, there was NORMAL drainage later, after the impact, but that has nothing to do with the discussion here.
I would also agree with your second thing about temp proxies. Right on.
If you want me to look at data on dates, I need you to point me to some of them. I’d love to look at them. But so far I haven’t seen any except one here and one there, deep in a paper somewhere.