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Davias' Astonishing Presentation to Asheville GSA on Carolina Bay origin
event April 5, 2012 comment 76 Comments

Michael Davias’ presentation this week to the GSA’s Southeastern Section in Asheville is simply extraordinary. Even better than last month at Hartford. I bet the sclerotic old geo-goats — and better, the know-it-all-because-somebody-told-me kids — were put on their heels

The fact is that no one knows how the hell these features came to be because no single explanation to date accounts for all the observed characteristics. But I am hopeful that at some point the scales will fall from their eyes and the mainstream will realize how unlimited the potential is for new discovery.

As Orville Wright said, “Isn’t it astonishing that all these secrets have been preserved for so many years just so we could discover them!”

The presentation builds from beginning to end, so make sure to read all the way through.

But first, here is Michaels’ own description of the session from a comment to an earlier Tusk post.

Greetings:

Thanks to all for their efforts in commenting here. Each and every fact does need to be considered and processed.

My experiences at the Southeastern Section Meeting of the GSA were once again beyond my expectations. There is a spectacular amount of good science being done, and it was great to have the opportunity to participate. As for my own talk, it was well attended and generated a good deal of helpful questions. I will be putting the presentation up on the GSA site shortly, and perhaps George can add it to the Tusk site as well.

The GSA, by offering me the opportunity to present my full catastrophic hypothesis, actually surprised me, and at the same time reassured me that the concept of open dialogue is as strong as ever in the geological comunitty.

Allow me to share a few take-aways. Regarding the wind-and-wave process, I did present Kaczorowski’s diagram of bay processes. The diagram’s caption states that a fan was blown across a water filled depression alternating (left to right, then right to let) every 15 min for four hours. The resulting is sort of an oval with points at both the top and bottom ends. No oval bay has points like that, and to suggest a rigorous 50% duty cycle for formative winds is a stretch, as far as I am concerned. I then noted that in the LiDAR, no bays looked like that.

The theme of my talk was to show that the published (!) literature had numerous mentions of the rim sand being: 1) homogeneous in grain size and chemical content bordering on pure quartz; 2) multi-meter deep deposits with NO stratigraphic structure to support either lacustrine, marine or eolian deposits; 3)no fossils of any type; 4) a sharp discontinuity to underlying sediments; 5)not related to those underlying deposits by chemistry or grain size distributions; 6) virtually no clay expect for some vary small lenses (which are acknowledged in the texts to be likely surface percolation artifacts); 7) sheet deposits which drape across well-provinenced slopes and terrace scarps.

A statement was made during the question period that the rims show structure. Interesting, because all the published literature I have read specifically highlight the lack of bedding, etc. Its part of the enigma, guys!

I made a very brief attempt at addressing the age issue. I must admit I would like to avoid placing “the date” chiseled in stone on this, as the data is quite fuzzy. I am proposing 40 to 45 K ago based on a few constraints, but the real date needs to come from the sand in the structural rim. I don’t want to appear to be contentious ( a respected academic geologist hit me with “you are being contentious simply by being here”) with the fine work being done in OSL, carbon and pollen dating, but it is quite clear that the current researchers have no interest in actually dating the rim sand. What are they dating? The contents of the bays and the obvious wind and wave generated surficial deposits. Steve makes some good observation, above, on choice of samples sites to date, such as Frierson Bay. I maintain there are thousands of more obvious locations to sample – if you wanted the rim dates. In fairness, the OSL dates done were done and paid for with research dollars aimed at identifying climate fluctuations – for which the dunes and the lacustrine deposits are best at providing, so they are doing what they need to do. But to extend that to proof of the structural rim dates is a step too far.

Much is made of those 60K and 100K dates: since the data is not published and defended as to location, process and provenance, I fail to see how they could be leveraged to slam the door on a catastrophic genisis. Yes, the antecedent surface is usually sand, and it might have last seen the rays of sun 100K years ago. So what. I feel I can make a case to validate a 43Ka date with the available OSL basket, if the two or three highest are thrown out and we recognize that any date that shows up since 43Ka is simply re-working. My understanding is that all of the OSL dates taken thus far are from the upper 50 cm of sand.

Recent literature is sparse, indeed, excepting “Abstracts from Program”, which refers to poster presentations. While that forum can and does relate good research to the community, they fail to qualify as “peer-reviewed literature”. We need more research. The same fine fellow who dinged me about being contentious for appearing at the GSA also credited the recent debate as being the motivation behind the resurgence of research into the bays. That can only be good.

At the end of my presentation Sunday, I proposed that the catastrophic hypothesis could be falsified by finding diverse OSL dates across the horizontal and vertical bulk of the Goldsboro Ridge sand deposit which underly and comprise the rims of numerous bays imbedded in the ridge. George Howard alerted me to the impending disection of part of the ridge during the construction of the Rt 70 Goldsboro Bypass project. New exposures there might provide just the canvas to draw those samples from. Now all I need to do is to raise some $$$ and entice some credible researchers to execute such a test.

Thanks again for your feedback,
Michael

Here is some video I took of Mike explaining his observations and hypothesis at the AGU San Francisco meeting in 2009 (I think?).

asheville gsa Carolina Bays Michael Davias

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  1. Described as a uniform sand sheet, mantled on top of pleistocene deposits sitting uncomfortably on top of the underlying layers, cross sections indicating extensive expanses with no known erosion zones from which production of the sand can be found and no fossils. Came from somewhere. The sky is looking like a good candidate. Geologists must be very uncomfortable with earth features derived from non-geologic processes which deliver geological features of enormous size and pervasive uncommon forms

  2. Hi Popeye –

    Impact is a geological process, although currently a very poorly understood one.

  3. Michael has found a really important focus, looking at the sand. The sand is really, really weird. In some places 10 meters thick, and good enough to use in glassmaking without doing anything to it, in most applications. There is NO stratification in it, and near the ocean, that is just not normal at all. That alone doesn’t make it from an impact, but in trying to explain it terrestrially, they can’t. It is obviously not from a hyper velocity impact.

    I am certain of that the CBs were caused by ejecta impacts, though dating puts it not at the YDB. If I am not mistaken, the ejecta that caused the CBs would have been subject to aerodynamic drag, just like anything flying through or falling through the atmosphere, and on its descent it would have gotten to a terminal velocity. And the best I can determine that terminal velocity would have been about 300 km per HOUR. Compared to a comet or meteor at 30 km per SECOND, that is a very gentle landing.

    But Michael also pointed out that everyone who discusses lacustrine or aeolian talks about reworking by those forces. They blow off the fact that the bays have clay bottoms that are ‘dimpled’ (in Davias’ words) – they are already hollowed. And the sand lays on the dimple, the rims, and the area outside the bays roughly evenly; it drapes over all of it, incise and out and over the rims. No lacustrine process can do that. No aeolian process can do that. Chris somehow pretnds that the lacustrine is accepted as the solution, when it was rejected LONG ago, and has never since then solved any of the objections to it. Not being lacustrine does not, in itself, mean it was an impact. But lacustrine it out of the picture. Period.

  4. Micheal was not able to go into his bubble concept very well at all in his presentation.

    I’d like to invite him to discuss that here – unless he has a paper he wants to do on it. I have some reservations about it, but definitely it has some good points.

  5. Steve –

    If there are “dimples” underlying the Bays, then perhaps the materials from those “dimples” was deposited nearby.

    Perhaps they may cap isotopically datable deposits.

    While the formation of the Bays has long fascinated many, my current thinking is that the HSIE will become a more important factor in changing public opinion and public policy.

    Ths HSIE was both recent and massive.

  6. Imagine if you were looking at an area where the ejecta from an extremely large impact event had fallen.

    Then imagine what that surface might look like if you could somehow erase all of the ejecta, leaving behind only the depressions the falling fragments made as they fell.

  7. Dennis, exactly my point. Thanks. The ejecta, though screaming at X thousand km/hr at ground zero, would be landing at much less velocity, due to drag both on the way out of the atmosphere and especially on the return downward. As much as drag could slow each bundle down, the bundle would possibly get to terminal velocity before hitting. As far as I can guesstimate re-entry would have been at maybe 2/3 of the Space Shuttle. The turbulence would have been terrific, all the while slowing it down.

    If they landed at under, say, 1,500 kph it wasn’t enough to blast the clay out. But, being clay, it compressed and squished out – but not explosively – into a rim shape. These landings would have been FAR, FAR short of hyper-velocity. Being friable and already shredded by turbulence, they landed like pancake batter or sludge, at an angle. Micheal is onto bubbles/foam being a mitigating force factor. He may be onto something; I am a bit edgy on how friable the ejecta was and if bubbles would have been sustainable through the ballistic trip up and down through the atmosphere. But I am open to it.

    Not being hyper-velocity, the crater would not follow the standard ‘almost all impacts are circular, period’ rule. Instead they would have milliseconds within which to spread out along the flight path as they hit. This would allow the shapes to be elongated toward ellipses. It remains to be seen why the impacts would have formed such shapes as seen. I do have my ideas on that.

    The incoming ejecta did not turn anything to plasma. The energy level was maybe 4-5 magnitudes below that. This may be generally less energy than an airliner crashing.

    By testing the weight-bearing capacity of the underlying clay (as is done when site testing for construction of buildings), it might be calculated what impact force might be needed to depress the clay (and form rims such as are seen) the amount seen in GPR transects. Working backward from that, one might determine the entire energy of all the ejecta found on land, then add a conservative X% for ones that would have landed in water (some are on peninsulas, ergo some could have landed between that and the mainland). With the ballistics and atmospheric effects known from NASA and elsewhere, the flight of each can be worked backward to launch velocities and the energy required to accelerate that much mass at that velocity. It gets complicated at the impact site, guessing what if any effect an ice sheet would have had, in terms of quantifying the energy and the mass of the impactor.

    Note on the LIDAR that when a CB has one edge on a downslope there tends to be no rim. This suggests that the downslope was enough to contain/prevent rim formation. With analyzing variations on this theme, one might be able to calculate the impact force required to form or not form or partially form a rim.

    So one might be able to put reasonable numbers to all this and come up with an overall picture of the event.

    Steve

    Ed – I agree with you on the HCIE being more important. But the CB impact was no piker, either. How many of the Impact database events put ejecta 1200km out to the side? And Tunguska’s blast pattern was only 70km wide, 35km per side.

    And can we please standardize the term? You use HCI sometimes, most call it the YDB.

    S.

  8. Something that’s needful is for one of the math-heads with access to a supercomputer to work up some numerical modeling to get a handle on how ejecta consisting consisting mostly of water and ice can really be expected to behave on the scale of the bays. After all, to account for all of the Bays (hwever they formed, I think the all happened at once)then a few tens of thousands of cubic miles of the LIS had to be lofted into a parabolic trajectory.

    It’ll be a damned complex problem. Because there is more than just the kinetic energy of inpact to account for. The power of the hydrothermal explosins need to be accounted for too. And we can be sure that those steam explosions would’ve been extremely powerful in their own right.

    Unfortunately, until actual planetary scarring can be confirmed in canada, or the Great Lakews region I don’t see anyone going to the effort to make those kinds of calculations. And without them, I’m afraid we are all just chasin’ butterflies in the playground and comparing notes when I comes to working out the actual formation mechanism of the bays.

  9. To be clear, I don’t think the hydrothermal explosions formed the bays. Rather, I think there were titanic hydrothermal explosions at the points of impact into the LIS that lofted a lot of the LIS as ejecta. How much energy the steam explosions actualy added to the equation is the tricky question.

  10. Yeah, Dennis, that seems to be the scenario. I am sure you are not laving out the explosive impact itself. Definitely steam – near to plasma state one would think. No reason ice should get off any ‘nicer’ than earth. And like you say, the steam is added to the impact energy.

    Hahaha – what does shocked H2O look like? Any icy spherules out there anywhere?

    Certainly if Michael is correct about Saginaw and the sandstone turning into quartz sand there should be some markers at Saginaw. The ice took the brunt of it, but how much is that? There was enough residual force to hollow out Saginaw Bay, so the reduction would certainly make the markers different. Meteor-think will certainly not recognize or acknowledge anything that isn’t 90% of meteor-normal.

  11. I’m thinkin’ that the proof won’t be all that hard to produce. And it will be in the K/Ar ratio instead of the traditional impact markers. Or the so called “full suite of impact markers” the impact community requires before they will acknowledge ET origin for an impact structure.

    The simple fundamental principle here is that as Potassium decays into Argon, it does so at a known rate. And the trapped Argon accumulates in the rock. But any melting event will allow the built up Argon to escape from the rock. So the K/Ar ratio is a good measure of the ‘age since melt’ of any rock specimen.

    Except for some small dyke formations that are about 2 million years old, the entire Canadian Shield has been volcanically stable for more than 2.5 billion years. If any of that heat of impact penetrated to the rocks of the sub-ice surface with enough intensity to melt the rocks below an impact point, then any melting event will have reset the K/Ar clock.

    Most geologists won’t even consider doing an age since melt test unless the location in question displays that full suite of markers.

    But the data from Lake Cuitzeo makes it abundantly clear that significant melting must have occurred at the impact points, and that we are looking for the signature, whatever it may be, of an airburst event. And by pointedly implicating cluster airburst events as suspects in the ‘Comets’ section of their new paper Israde-Alcántara et al. have opened the door to the search for, and consideration of, a new, and more complete set of impact markers; one that includes ablative airburst phenomena.

    But put simply, the proof of impact into the Canadian Shield will be any rock specimen that returns an age since melt of only thousands of years. And an ‘age since melt of 12,900 years would be conclusive proof of the YD impact event no matter what other evidence might be at the site.

  12. Though K/Ar is a useful dating tool, as usual, rather completely wrong, Mr. Cox, and very optimistic.

    Field data is expensive to gather, and those cossts have to be be paid for by somebody.

    What have been impact markers are shocked quartz, bediasites, and PGE anomalies, and if the Perigee Zero hypthesis is correct then some variant of those should be found in the Saginaw Bay area.

    As far as the Bays themselves go, nowhere near enough field data has been gathered to model them mathematically as secondary impacts.

    If you ever find any Boshough type impact structures and can get any competent geologist to confirm them please let us know.

    Point detonation airbursts without preservation of momentum are well attested by field data and well modeled, and their fire effects are well known as well.

    They are likely to entirely expalin the new data from Mexico.

  13. Question:

    What was the impactor composed of? Pure quartz sand perhaps? A serious drawback do the sand being derived from a saginaw impact is the uniformity in grain size. A study of ejecta might be expected to show a wide range of grain size from very small to rather large, even if the process was physically constrained, to result in such uniformity strains believability, and there should be some ejecta that exceeds the constraints if they exist. I ask this with no knowledge concerning the expected breakdown of the bedrock proposed as the parent material of the sand. It may well be that the bedrock was shocked into it’s constituent grains by the impact ….. Perfectly.

  14. Ok Ed,

    Your delusions of grandeur are biting you on the butt again. It’s time for another reality check. You are not the Dean of impact research, or the final word on the subject of impact science. The simple reality factor here is that in spite of your overinflated sense of self importance in this matter you are nothing more than another opinionated amateur researcher suffering from a severe case of confirmation bias who has no academic standing whatsoever.

    So tell us Mr. Expert on the dating of rocks. My own mentors on the subject are PhD level physicists. But since you posses no academic credentials at all, perhaps you will be so kind as to tell us where you studied to attain the level of expertise you presume to? And who will certify that knowledge is real since you also posses no academic degrees in any science, and have never published a single word in refereed literature?

  15. Ed said:

    "Point detonation airbursts without preservation of momentum are well attested by field data and well modeled, and their fire effects are well known as well.”

    Bullshit! Says who? What field data? Well modeled by who? What fire effects? Well known to whom?

    References in refereed literature are required for such authoritative statements. Especially since you are an opinionated amateur researcher who possesses no degrees or academic standing whatsoever.

    But from an honest to PhD physicist who’s made a carrier of studying the physics of impacts there’s The Nature of Airbursts and their Contribution to the impact threat And we can read:

    Ongoing simulations of low-altitude airbursts from hypervelocity asteroid impacts have led to a re-evaluation of the impact hazard that accounts for the enhanced damage potential relative to the standard point-source approximations. Computational models demonstrate that the altitude of maximum energy deposition is not a good estimate of the equivalent height of a point explosion, because the center of mass of an exploding projectile maintains a significant fraction of its initial momentum and is transported downward in the form of a high-temperature jet of expanding gas.

    The time scale of this descent is similar to the time scale of the explosion itself, so the jet simultaneously couples both its translational and its radial kinetic energy to the atmosphere.
    Because of this downward flow, larger blast waves and stronger thermal radiation pulses are experienced at the surface than would be predicted for a nuclear explosion of the same yield at the same burst height. For impacts with a kinetic energy below some threshold value, the hot jet of vaporized projectile loses its momentum before it can make contact with the Earth’s surface. The1908 Tunguska explosion is the largest observed example of this first type of airburst. For impacts above the threshold, the fireball descends all the way to the ground, where it expands radially, driving supersonic winds and radiating thermal energy at temperatures that can melt silicate surface materials. The Libyan Desert Glass event, 29 million years ago, may be an example of this second, larger, and more destructive type of airburst. The kinetic energy threshold that demarcates these two airburst types depends on asteroid velocity, density, strength, and impact angle.

  16. Greetings:

    Popeyesmotto posed some pertinent questions regarding the grain sizes seen, and a nod to the possible contribution from the impactor itself. Impact research has identified that a “winnowing” effect is seen in ejecta curtain walls. A possible effect is that the sand grain size should grade from coarse to fine over the range of deposition. The finest particles are seen as being suspended in the upper atmosphere and distributed as “dust” worldwide.

    One model for fresh comets (not those de-gassed from hundreds of interactions with the sun) is a very low density (~0.6 g/cm3.) assemblage of hydrated silica: H20 & SI. Could that set of ingredients precipitate SI02? And also to the point – what would a dusty snowball impact look like? I am assured by impact specialists that it would not differ from that of a solid iron impactor. Realy?

    – Michael

  17. Hi Mike –

    If there were H20/SI asteroids, none of their fragments would make it to Eartth as meteorites.
    If entry spectra were available, they might be indicative of this type.

    That water would survive hydrocarbon outagassing in a comet is not likely.

    So where does that lead? The obvious need is to examine the Saginaw Bay area. Also, areas that need to be examined are the clay levels underneath the Bays. And the areas surrounding them for tertiary deposits.

    Perhaps archaeological resistivity survey tools could be used for the last, followed by excavations.

  18. I have no need of your ad hominem crap Ed

    Since I have found the actual scientists of the YDB team to be generously forthcoming with such information, I have no need of you, or the Meteorite list, if I wish to find valid references or recommended reading in refereed literature concerning isotopic methods, or impact research.

    As for as point detonation of airbursts go you obviously have no clue of the actual physics, or that preservation of momentum is synonymous with conservation of energy. And it’s also obvious that you have no clue of the actual science that’s been done at Sandia Labs on their Red Storm supercomputer regarding the modeling of airburst phenomena. The modeling of airbursts at Sandia Labs represents the state of the science. And the obvious reason you would bring it up and then say you have no intention of talking about it when references are demanded is because your delusional claim that “Point detonation airbursts without preservation of momentum are well attested by field data” is a stupid lie.

    Since you rode me for two years about some places you called my features without reading a single word of what I had actually written, and have proven beyond all question that when you do read something you have the reading comprehension skills of a 10 year old, and since you never cite a single valid reference in refereed literature to support your own stupid and negative rants, or your baseless claims to immense knowledge and authority, your proven lack of academic integrity makes it impossible to take anything have to say you seriously.

    Your claim to have the inside scoop on impact events on this continent based on your own subjective interpretation of Native American oral traditions has never been confirmed by anyone. And frankly, since you refuse to provide the names of your actual sources for the stories you recant, or supportive archeological references in refereed literature that can positively connect one of those tales to a real impact event or structure, I see you as not even being as reliable as Velikovsky.

    And since my extremely low opinion of your proven lack of academic integrity falls even lower with every stupid and negative rant you write, I most certainly have no intention of ever wasting the time required to read your silly book.

  19. Ed –

    Your entire comment at 9:17 pm last night is unimpeachable, from my POV.

    Yes, without impact markers, Saginaw is just a reasonable guess.

    And no airburst is going to explain Lake Cuitzeo. Nor Belgium/Netherlands.

  20. @Dennis 5:32 pm:

    But the data from Lake Cuitzeo makes it abundantly clear that significant melting must have occurred at the impact points, and that we are looking for the signature, whatever it may be, of an airburst event. And by pointedly implicating cluster airburst events as suspects in the ‘Comets’ section of their new paper Israde-Alcántara et al. have opened the door to the search for, and consideration of, a new, and more complete set of impact markers; one that includes ablative airburst phenomena.

    Dennis, I would have to disagree on the airburst. I can’t see the energy in an airburst needed to loft to the Carolinas.

    Also, cluster airbursts I can’t see making ONE Saginaw Bay.

    Ablative? Ablative melts/blows off the skin. It is not a deep phenomenon, not that I know of. Correct me if I am wrong.

  21. It’s a question of the scale of the event Steve, and number of fragments in any given cluster. But it would only be “ablative” if there were no ice to vaporize.

    Pete Schultz’s work indicated that a fragment as much a mile wide could’ve hit the LIS and left no trace in the sub-ice surface.

    If evidence is ever found in the canadian shield of enough heat to have penetrated a two mile thick ice sheet and melted some of the sub ice surface, then it follows that you also have evidence of enough hydrothermal explosive force to loft large chunks of ice a long ways.

  22. It’s funny though; if “no airburst is going to explain Lake Cuitzeo” as you say, then one is left wondering why the YDB team would propose such a thing, or cluster airburst events for that matter.

  23. If you guys could quit fighting among yourselves for just a few moments I can recommend you go over to ‘The Scared Archeologist’ at thesubversivearchaeologist.blogspot.com/ and peruse the last couple of posts where he attempts to examine the Younger Dryas Impact Hypothesis and fails miserably, and then freaks out at the first sign of trouble and then shuts down the comments.

    I was just getting started too! These guys sure have thin skins.

  24. @Popeye at 9:36 pm:

    What was the impactor composed of? Pure quartz sand perhaps? A serious drawback do the sand being derived from a saginaw impact is the uniformity in grain size. A study of ejecta might be expected to show a wide range of grain size from very small to rather large, even if the process was physically constrained, to result in such uniformity strains believability, and there should be some ejecta that exceeds the constraints if they exist. I ask this with no knowledge concerning the expected breakdown of the bedrock proposed as the parent material of the sand. It may well be that the bedrock was shocked into it’s constituent grains by the impact ….. Perfectly.

    Don’t be so hasty to rule out uniformity of grain size. Keep reading….

    Michael’s idea of steam is, I think, a valid consideration. Compressed gases and water in magma is what pulverizes magma into ash, as soon as it exits the mouth of a volcano. I think an ice sheet impact has parallels to this – the sudden creation of vaporized water. The suddenness is even MORE sudden. A volcano only releases the pressure as the magma reaches the orifice. An impact releases it all at once, in milliseconds. Davias estimates the launch velocity at 22,000 km/hour. Let’s accept that for the moment as something close to the ballpark. That equates to about 6 km/sec. It is about 1/5th the velocity of a common impactor, and that doesn’t sound terribly out of line. So, the ejecta is traveling UP at 6km/sec through maybe 2 km of ice, tops. That takes 1/3 of a second. Roughly, I see that as the entire time of the release of ALL the water vapor.

    That is expansion on a ridiculous level. I would expect with such expansion that the pulverization of whatever solids are present would be, if anything, perhaps a magnitude greater than normal volcanic ash is subjected to.

    Not taking it as a final answer, but at is a nice plot of the Distance From Volcano vs Ash Mean Grain Diameter for Mt St Helens in 1980. On the plot, the ash size close in starts at >4 mm and quickly diminishes. It seems that between 300 and 600 kms the ash size stabilized at 0.04 mm. Closer in larger particles fell. 4 full mm was the average at about 50km distance, and at about 150 km the size was about 0.1 mm. This is one example where distance appears to have acted as a sizing screen, as it were, and for 400 km the grain sizes were consistent. That seems to be supportive of an impact yielding consistent grain sizes – as long as the landing site is not too close to the impact and the grain size was not large.

    FWIW, this from Wiki: “The violent nature of volcanic eruptions involving steam results in the magma and solid rock surrounding the vent being torn into particles of clay to sand size.

    Since we are talking of ice at ground zero, this scenario abets the argument of sand-sized grains coming from an ice sheet impact.

    I am still trying to find what the actual grain size was in the CB area. So far, no luck.

  25. Re-posting the screwed up part of that comment three comments up:

    Not taking it as a final answer, but at http://volcanoes.usgs.gov/ash/images/ashsize-msh-1980.gif is a nice plot of the Distance From Volcano vs Ash Mean Grain Diameter for Mt St Helens in 1980. On the plot, the ash size close in starts at >4 mm and quickly diminishes. It seems that between 300 and 600 kms the ash size stabilized at 0.04 mm. Closer in larger particles fell. 4 full mm was the average at about 50km distance, and at about 150 km the size was about 0.1 mm. This is one example where distance appears to have acted as a sizing screen, as it were, and for 400 km the grain sizes were consistent. That seems to be supportive of an impact yielding consistent grain sizes – as long as the landing site is not too close to the impact and the grain size was not large.

    FWIW, this from Wiki: “The violent nature of volcanic eruptions involving steam results in the magma and solid rock surrounding the vent being torn into particles of clay to sand size.”

    Since we are talking of ice at ground zero, this scenario abets the argument of sand-sized grains coming from an ice sheet impact.

    I am still trying to find what the actual grain size was in the CB area. So far, no luck.

  26. Dennis –

    It’s a question of the scale of the event Steve, and number of fragments in any given cluster.

    Yes and no. It depends on whether the impactor was from the Taurids or if it was a bogy that came by earlier inside the Roche Limit and was broken up one orbit before impact. Yeah, I know, Napier and Clube. That is the best bet, but certainly not the only one. As things stand, we are talking about 40,000-30,000 years ago, not the YDB. And that may be too early for the Encke progenitor.

    But it would only be “ablative” if there were no ice to vaporize.

    Probably, but you are the one who brought up ablative. To whit: “…Israde-Alcántara et al. have opened the door to the search for, and consideration of, a new, and more complete set of impact markers; one that includes ablative airburst phenomena.” My own point was that an on-ice impact would not be ablative. Also an impact cannot be ablative, so if you were talking about an ablative airburst over Saginaw, I don’t think I agree.

    Pete Schultz’s work indicated that a fragment as much a mile wide could’ve hit the LIS and left no trace in the sub-ice surface.

    Something comes to mind about him saying if the thickness was greater than the impactor diameter. If enough energy was left over to scoop out Saginaw Bay, then it was a truly big ass impactor. The world may have been lucky that it hit on the ice, then. A land impact that big and it would have been much worse, and same goes for an oceanic impact.

    If evidence is ever found in the canadian shield of enough heat to have penetrated a two mile thick ice sheet and melted some of the sub ice surface, then it follows that you also have evidence of enough hydrothermal explosive force to loft large chunks of ice a long ways.

    The LIS may have been 2 miles thick, but wasn’t Saginaw pretty near the edge? I’d make it more like 2km, maybe a bit less.

  27. Thanks, Dennis for the tip. I’ll give that a try. On WattsUpWithThat.com (also WordPress), I’ve lost an occasional comment while sending. Windows Live writer would give me a backup, just in case a comment fails to go.

    Funny how I’ve never heard of Live Writer before. I usually know about things, even if I don’t use them.

  28. Hey guys, if you could quit arguing amongst yourselves for a few minutes, you would notice that some yahoo from UTAH retroactively removed the reference to Kennett et al.’s latest paper from the Younger Dryas Impact Hypothesis page, clearly without even having read the paper.

    His name is Michael Simpson, and you can comment on his blog here.

  29. That may be so, but he retroactively removed all references to a new result from the relevant wiki page, based only upon APPEAL TO AUTHORITY. I feel I need to confront that and that alone.

  30. Nevertheless, there was still no reason to remove a relevant new result from a wikipedia page.

    Wikipedia is supposed to be self correcting. I have corrected this guy, so I’ll just have to wait and see if he can take some criticism on his blog.

  31. Greetings and thanks for a beautiful and refreshing dialog. I’m going to launch from the cliff right into this debate, no doubt making lots of errors on the way, so please be kind. I still have lots to read on this and all of the many related highly technical topics, and being a tad dyslexic doesn’t help that effort, nor do three kids and too much laundry to do. My main background is not Earth Science, but I have a BS in Engineering Science and Mechanics w/ a bunch of Aero and Astro stuff while in school and since.
    It seems like y’all are on the right track with backtracking CB major axes all back to some common loci, and in the process accounting for earth’s rotation during loft time, etc. I finally got to some of that Zero Perigee stuff today. But shouldn’t it be Slightly Negative Perigee? (joke) There are some distractions in the thread above which I would like to point out although based on the date of posts y’all have probably covered these already – so here goes.
    I’ve been aware of the Sandia resources since the estimated downsizing of the Tunguska object. Saw the ‘hammer effect’ sim w/ rigid surface boundary condition, the air burst sims that didn‘t contact surface, and the one modeling surface ‘entrainment’ for the Glass Desert event, but I haven’t seen everything that’s come out of that camp since if there is much more, so direct me to some links if there is more juicy Sandia goodness now.
    I have to say that when I was working in aerospace, first on an interplanetary mapping spacecraft (ill-fated Mars Observer, one of those that never made it to Mars) and later when I worked as an orbit analyst and propulsion engineer on a ComSat fleet flown for the Navy by the Air Force, I saw lots of stuff that I didn’t believe. We know that those complex magneto-hydro-‘magico‘-plasma-dynamic codes were developed for nuclear weapons research, and we should therefore assume that much of what they can do is need-to-know only. Asking the right questions is critical when commissioning work of that nature, and even then the answers may still be sensitive or of a secure nature. That being said, Dr. Boslough seems to understand what we’re trying to get at and seems to be hinting to steer us in the right direction. Time to call him.
    I bring this up since we obviously still need lots more Sandia modeling! Air burst ablation of surface is just one example. Water impact and ice sheet impact simulations are in critical demand now as I see things. For all angles of incidence and a wide range energies. And in terms of the critical energy value where the fireball/fire column does vs. doesn’t reach the ground, an expanded set of non-dimentionalized cases covering a range of velocities and masses would be extremely helpful as a handy reference. Similar reference parametric relations were developed during the cold war for nuclear blast damage, crater size/volume, etc. for yield and detonation altitude, etc., all condensed into nice circular slide rules. Scary, but extremely useful if applicable to Earth impacting astro-science. Sandia just needs to recreate those w/ the downward momentum effects accounted for. Surface involvement is another story….
    Could a super heated hypersonic plasma jet of a billion tons punch through and under the ice sheet? Then what happens? What if there is water under the ice? You see what I’m getting at – lots of variables. The original Sandia vertical column reflects off of the rigid surface boundary condition, but that’s not realistic at all, and the entire set of circumstances that are of interest to us depend on what happens to that surface upon contact. All the way down/in/under/through/around etc whatever is being impacted. Think about shallow impact angles and a thick sheet of ancient ice here for a moment. Amen.
    Regarding energy, the best way to dissipate energy, astronomically large amounts of it, is though heating. When you (shock) heat lots of cubic miles of ice, what do you get? And what is the volumetric ratio of ice vs. steam at the same temperature, vs. even several hundred or several thousand or several tens of thousands of degrees hotter? Try to imagine an energy balance and what gets absorbed by what. Steam shredding everything to the same (small) grain size doesn’t sound far off. But if steam shredded something to make the sand at the ET impact site, how did it get to the CB sites? What’s the vehicle?
    The powerful steam explosion on/in/especially UNDER the ice sheet is of critical importance, not just for it’s ability to shred and pulverize whatever is in the area, be it locally resident or astronomically delivered. Most of all for the potential to loft chunks of ice sheet while embedding whatever it feels like into that ice. Supernova titanium or Michigan sand. And steam isn’t all. Check your steam tables for the 100,000 degree range. Pretty sure its plasma. Plasma, plasma, plasma. Mmmmmm….
    There is also an issue of velocity and mass (energy). If the Zero Perigee (ZP) hypothesis is true then the velocity would likely have been very low compared to a comet or even a fragment in freefall from Oort or from some captured orbit within the inner solar system, or perhaps even very low compared to an asteroid. ZP hypothesis bothers me a bit but I’ve only had a few hours to stew on it yet. Anyway, w/ lower velocity, a bigger mass can make up for the total energy, but lets remember that momentum energy varies only linearly w/ mass but kenetic varies w/ the square of velocity. So to make up for a lower velocity, the diameter may become larger than the thickness of the LISheet, then your scenario takes on new complexity. Bigger bullet. Call Boslough.
    Carolina Bay sand grain size is another perfect example of the need for better super computer simulations, as I’ll explain. Each bay is large. Many grains of sand! Arrived there in clumps? Big clumps. Carried there that way – big clumps? The observations of grain size vs. distance traveled from impact is good for individual grains. That is NOT the case with CB (clumps of) sand if an ice-sheet-blast-launched iceberg is what delivered it. Studying grain size fining over eject distance for this problem is just a waste precious minutes, IMHO. That plasma concept is stuck in my brain. Vorticies of plasma.
    Regarding CB impactite velocity: I believe the likely impact velocity based on the range to the CB sites was transonic or supersonic depending on the size of each projectile. This is because of the likelihood that they were relatively large impactites on exo-atmospheric suborbital trajectories. I can tell you this from studying that regime and also with lots of experience in freefall. So when the CB impactites landed, if they were big at all, they were no where near just a few hundred miles per hour. No chance. Not from suborbital exo-atmospheric unless they are very small compared to the size of the Bays themselves…. Now if they were smaller or soft, different story. They were probably not soft because they held together for that ride, I think. But remember the plasma and the vorticies.
    This bloody computer spells worse than I do if that’s possible. Hard to imagine.
    Whatever seems to have rained down from the original ET impact to form the Carolina Bays, we really don’t know is how big those things were. It seems like the range of different size CBays must have been formed by different size projectiles, right? It feels wrong that a big chunk of rock hard ancient ‘glacial’ ice doesn’t leave a deep crater or a trail as it bounces and then rolls to a stop. This makes me imagine soft slushy sandy balls of very weak or “highly fatigued” ice w/ lots of fractures and IR softening (I completely just made that up!) How can they travel so far and then splash away to nothing but shallow sand ridge rings? (he asked naively) Keep reading!
    Larger ones would conserve velocity better and require less initial (launch) velocity to reach a give range. Smaller ones would slow down faster and hit more vertically, lower cannon ball factor, and that I believe is critically important. Naturally there would likely be some distribution of initial ‘launch’ velocities of these puppies so more variables to sort, but…. The eccentricity of the CB ovals should be an indication of the impact angle of formation, which combined w/ range from ET site may give more clues as to size of CB impactites. That size thing is puzzling. Even a small impactite that splashes to leave just a ring of its formerly suspended aggregate payload should leave evidence at the point of impact, right? And they must have had substantial mass to fly that far, right?
    When trying to solve any complex multi-variant problem and running into deep confusion from too much information in that sub-frame, we have to back it out to the super-frame. Think about mass transport. The origin of material comprising the sand before the impact event sequence started was either from 1) ET impactor, 2) from within the LISheet, 3) from the surface below the LIS, 4) from the CB locations themselves (or somewhere underneath), or 5) from somewhere in between the ET impact and the CB sites. Anyone care to place bets now before we spin the wheel?
    As for item #1, imagine a 100 meter diameter piece of comet staying together through a right angle turn while decelerating some miles per second, all in one millisecond. Maybe not. Now imagine a 1 km chunk w/ the same jolt. I don‘t think so. I’ll skip #2 for the moment. Item #3 is sand (or material for making same) from below the (mile thick) LISheet, under the downward force a colossal astronomical impact. I suppose anything is possible. Was there a source for plenty of equi-sized grain sand already under that Ice Sheet, maybe so. I’m having trouble imagining the mechanism, but I can’t explain the Fenambosy Chevrons in Madagascar either. From the deep ocean floor, REALLY?
    The nature of the CB sand may help here in terms of isotopic signature and all other possible details for origin ID. Item #4: If a giant shock fractured, steam blasted, trans-atmospheric, transonic chunk of ice, only a hundred meters big or so, hits hard ground, would it splash, or would it crater or maybe even bounce? If it bounces wouldn’t it leave a chain of marks? What about over sandy soil: could landing impact liquefy our poor tired Ice Sheet traveler? Could liquefaction in the traumatized basement cause percolation of sand to the surface or nearly so? Of only one size of sand grain? What about a 500 meter chunk? Could liquefaction and percolation happen mostly at the rim surrounding the impact “point” at some distance outside the impact, leaving big Bay rims from just little impactites? I’m just throwing it out there. Please contain your laughter! Obviously the sand should tell us where its from, we just need to know how to ask – what language to form the question with.
    So I’d like to use a few life lines here please. Questions: What is found at the western bays? Is the sand the same? Are the formations the same? Underlying structure? Ok, call me back on that one. So I’ll end this soon but about that Zero Perigee idea, I guess it’s the multiple passes to lower the apogee that doesn’t work for me. The reason that works with spacecraft is because they have a low enough ballistic coefficient to lose momentum in the far upper reaches of the ionosphere. For that to work with something really big that by definition has a higher ballistic coefficient it would either take 20,000 small incremental passes through the upper atmosphere over a crazy long period while the Earth is moving an impossibly long way through space, or several passes through the lower, thicker layers. “Odds are against it.” Maybe one or possibly two passes before impact. Anything more and Earth has moved on.
    Of the possible transport vehicles in our super-frame problem of getting sand from ET impact to CB sites hundreds of miles away, we have two options remaining. Item#2, chunks of LISheet, seems like a great answer because for some unknown reason the Ice Sheet had plenty of sand of essentially equal grain size already in it, and also because the icebergs magically disappeared after landing, leaving no central impact signature upon landing, even though they were solid enough to be launched suborbital w/ 5,000 Gs acceleration (a complete guess so don‘t get excited) from an astronomical impact blast. Oh yes, and they were ½ mile in diameter on average (another complete guess, please stay calm). But no craters. Is anyone feeling the love for that answer, because I’m actually having some trouble here.
    No other substantial mass remains at the CB sites save the sand (do I understand this correctly?) which didn’t get there just by holding hands, if you know what I’m sayin’. Wait – what about answer #5? Remember the vortices of plasma that we get with ET impacts – and what we get w/ moving plasma is electro-magnetic domination of the dynamic equation. The Sandia factor. That’s right, I’m thinking the sand held hands. What do we know about natural yet freakish cases of plasma torrid behavior? Ball lightning. Too simple.
    I’m a risk taker. That’s why I live on the coast of a large ocean in densely populated NYC and at the same time read all the catastrophist lit I can find. Its quite thrilling actually, just takes forever to get through it all with this dyslexia ‘feature‘ of mine. Hopefully the Gradualists will never read this far! Weather that sand was excavated, liberated, scooped, trenched, chemically formed, or delivered to the ET impact as payload, doesn’t matter for this hypothesis. But you are in the Catastrophist camp so ‘brace brace brace‘, because now I’m going to tell you what happened to the sand.
    The sand found itself in the ET impact environment, a difficult place to imagine. It woke up on fire. It was not happy sand. High temperatures and hellish vorticity in an expanding fireball literally like the surface of the Sun. Hypersonic shock expansion, unconstrained above by an atmosphere barely as deep as the fireball is tall. Suprsonic vorticity with as much integral angular momentum as a small spinning planet. Electro-hydro-dynamic mayhem. The Sandia factor. The Boslough scenario. (Who ya gonna call?)
    Plasma balls of a variety of sizes formed and developed in thousands or tens of thousands of cells within the roiling conflagration as the impact progressed. Sand was trapped along with any and all suspended, ionized and otherwise very upset matter within, both gas and solid, and whatever other forms of matter we have not yet discovered are possible in those conditions. And at the floor of the whole cauldron is the big bang of steam explosions, with an extra push from the rebounding surface beneath, as if more push were needed.
    The cells of looping plasma were carried the only way the mess could expand, up within the fireball upon the initial expansion, many of them lofting above most of the atmosphere in a superheated plume like we saw over the limb of Jupiter in ‘94 with Shoemaker–Levy 9. All in a matter of seconds while the temperature remained very high. As the blast wave rose it expanded, forcing the plasma balls out sideways with no more atmosphere to constrain cross-range movement. With substantial cross-range velocity imparted, the plasma balls containing thousands or tens or hundreds of thousands of tons of encapsulated matter (mostly sand) followed ballistic trajectories to their CB landing sites. What does ball lightning do to stuff it touches? Look for those signs in the Carolina Bays. Plasma scorching, high current discharge and arcing to ground through nearby conductors is all that is left behind. And some sand, very happy to get some rest after a rather violent flight.
    And how does sand stay encapsulated in giant ball lightning cells? How do giant ball lightning cells stay together while descending in freefall? How fast do they fall? What is their ballistic coefficient? Will sand only stay inside ball lightning at a narrow range of grain size? Come on now, I can’t give it all away that easily. You have to call Dr. Boslough. He will tell you the answer. He will show you the Sandia factor. Then it will all become clear.
    So there you go. I’m going to bet against the Zero Perigee hypothesis (no offense, please believe me, as the earth spin correction w/ probabilistic modeling of all of those CB axes was really quite impressive!), but in the very same post I’m layin’ it all out there with BALL LIGHTNING as my proposed sand transport vehicle. Its just so crazy its perfect for this Catastrophist venue! Just remember I have y’all to thank as my inspiration! I just hope you didn’t spend as much time reading it as I did writing it. Wife is gonna kill me when she finds out what I’ve been up to. So is Dr. Boslough!

    Thomas Harris
    ‘Independent Researcher’
    Brooklyn NY USA

    If a single shred of this is useful I would love to hear about it. I’m just trying to keep the dialog interesting, and honestly this debate is so insanely captivating that it does keep me up at night. Your fault.

    -TH

  32. Hi Tom,

    Plasma is described my many folks as the fourth state of matter. Most folks are confortable with the definition of the first three, i.e. solid, liquid, vapor. The plasma you see in your PC monitor is an example of a cold plasma. It’s got a lot of free electrons. But it doesn’t have a lot of mass. The thermal plasmas that might be produced in an impact event though are a completely different animal.

    I’ve noticed that among those talking about plasma phenomena, most aren’t really very clear on where the dividing line between an extremely hot, and incandescent, vapor and plasma lies. For that you look to the electrons.

    When an incandescent vapor is heated enough that the electrons get stripped from the nuclei, all those free electrons make it electrically conductive. It’s that point of being electrically conductive that makes it a plasma. Get it hot enough, and any element can become a super-conductor. Once it does, it can be contained, and channeled by magnetic fields; even magnetic fields of it’s own making. So a plasma can sometimes behave almost like a thing alive. But it’s hard to maintain such a plasma in a self sustaining state unless you have the mass of a star to work with. Thermal plasmas loose energy too quickly by IR radiation. And once it cools enough that the free electrons get bound up in the nuclei of atoms again all you have left is an extremely hot, incandescent vapor.

    I got curious about the potential for an airburst to be dominated by plasma phenomena. So I looked into the possibility. I‘ve had a conversation or two with Dr. Boslough about airburst phenomena. And that’s one of the questions I put to him. He pointed out that in the simulations they’ve done at Sandia labs the thermal plasma conditions only exist very high in the atmosphere in the early stages of atmospheric entry. And that even in a very large event like the one that produced the Libyan Desert Glass, the electric plasma conditions don’t make it to the surface.

    According to Mark’s simulations we can expect that, at ground level, any planetary scarring of even the largest of airbursts will be almost 100% the work of the IR pulse, coupled with efficient stripping, and ablation of any melted surface materials by the supersonic winds of the impact vortices.

  33. OK guys and gals. You are obviously a very good natured group for not ripping me a new one after that post. Appreciated. I’ve now had a long and informative lunch w/ Michael Davias. The poster is amazing! And now I am armed with some juicy shallow angle impact papers.

    Turns out the Carolina Bays are a meteorological phenomenon, as I explain below.

    George and Dennis, you guys are my heros. Dennis, I completely hear you on the “waaaaaaay too little heat for sustained plasma” call. I was realizing that as I wrote the Ball LIghtning paragraph at 2:45 am, too vested in the effort to give up at that point. The shallow impact is a relatively cold one with the majority of the ejecta jet reflecting from the surface and heading down range in a spray of somewhat less speed than it comes in at. Dominating mechanisms are oblique shock and shearing forces. Its actually good news because with less volume fraction of plasma if any, the ‘hot zone’ of the shallow impact should be easier to simplify w/ some basic assumptions.

    The situation is not good. I have no time to spare professionally, and yet I am compelled to write a shallow angle impact paper and have it reviewed by all my former professors and room mates who are now engineering PhDs.

    “Characterization of the ‘hot zone’ in low angle hypervelocity impacts” I’m guessing that to assume dominant mechanisms are oblique shock and shearing forces, the entire bolide travels through and is transformed by the ‘hot zone’, and the energy of the collision may be calculated by the volume of crater (instead of just the mean diameter) which seems relevant since these seem to produce shallow craters, some fancy curve matching may then be used to describe the development and evolution of the hot zone and its characteristic shape. And here is the important part – it should be a non-dimentionalized treatment written as ratios of opposing influences, so the result is a parametric that allows ease of tweaking to match whatever case you are interested in. Its a mix of Thermodynamics and Engineering Mechanics so square in my area.

    Anyway Michael Davias seems right on the money with the foam spray on the ocean beach idea, which I immediately rejected upon hearing it the first time (sorry Mike!). The ocean is space w/ the bolide floating ashore and crashed by the waves. Shore is the Earth. The foam is the sand.

    The bubbles are the domes of sequestered atmosphere that became trapped under the wet sand blanket as it reached the ground, those domes bursting from overpressure from the weight and downward momentum of the wet sand blanket, depositing the slurry mix in the form of the emplaced CBays. Maybe some hail in there too, as that seems to helps the flow of the slurry to meet the observed characteristic flow of emplacement.

    How did he know that?

    I’ve already theorized a series of mechanisms to get the sand from impact to CBay emplacement, but I’ll let him fill you in with his own cognitive filter. Its pretty basic! (of course that is a joke) The bays open as the cohesive wet slurry blanket is destabilized from beneath when it reaches the ground, w/ overpressure force of trapped airmass overcoming the cohesive force of the wet blanket. This model explains all of the many incredibly beautiful features observed in this confounded puzzle. I’ll try to make up some diagrams.
    Cosmic Tusk wet blanket trapped air domes

    OK guys and gals. You are obviously a very good natured group for not ripping me a new one after that post. Appreciated. I’ve now had a long and informative lunch w/ Michael Davias. The poster is amazing! And now I am armed with some juicy shallow angle impact papers.

    Turns out the Carolina Bays are a meteorological phenomenon, as I explain below.

    George and Dennis, you guys are my heros. Dennis, I completely hear you on the “waaaaaaay too little heat for sustained plasma” call. I was realizing that as I wrote the Ball LIghtning paragraph at 2:45 am, too vested in the effort to give up at that point. The shallow impact is a relatively cold one with the majority of the ejecta jet reflecting from the surface and heading down range in a spray of somewhat less speed than it comes in at. Dominating mechanisms are oblique shock and shearing forces. Its actually good news because with less volume fraction of plasma if any, the ‘hot zone’ of the shallow impact should be easier to simplify w/ some basic assumptions.

    The situation for me is not good. I have no time to spare professionally, and yet I am compelled to write a shallow angle impact paper and have it reviewed by all my former professors and room mates who are now engineering PhDs. I’m ready to start with the impact characterization paper, then the trajectory analysis to describe the ascent and coast phases of the ejecta blanket, and finally a detailed analysis of the descent phase, culminating in blanket lay-down and CBay emplacement. I’ll even get another degree or two out of the deal if necessary. So who’s got the research money?

    “Characterization of the ‘hot zone’ in low angle hypervelocity impacts” I’m guessing that to assume

    1) dominant mechanisms are oblique shock and shearing forces, the entire bolide travels through and is transformed by the ‘hot zone’, and
    the energy of the collision may be calculated by the volume of crater (instead of just the mean diameter) which seems relevant since these seem to produce shallow craters,
    then some fancy curve matching may be used to describe the development and evolution of the hot zone and its characteristic shape. And here is the important part – it should be a non-dimentionalized treatment written as ratios of opposing influences, so the result is a parametric that allows ease of tweaking to match whatever case you are interested in. Its a mix of Thermodynamics and Engineering Mechanics so square in my area. I have to call my former fluids prof, the shock wave guru.

    Anyway Michael Davias seems right on the money with the foam spray on the ocean beach idea, which I immediately rejected upon hearing it the first time (sorry Mike!). The ocean is space w/ the bolide floating ashore and crashed by the waves. Shore is the Earth. The foam is the sand.

    The bubbles are the domes of sequestered atmosphere that became trapped under the wet sand blanket as it reached the ground, those domes bursting from overpressure from the weight and downward momentum of the wet sand blanket, depositing the slurry mix in the form of the emplaced CBays. Maybe some hail in there too, as that seems to helps the flow of the slurry to meet the observed characteristic flow of emplacement.

    How did Mike know that?

    I’ve already theorized a series of mechanisms to get the sand from impact to CBay emplacement, but I’ll let him fill you in with his own cognitive filter. Its pretty basic! (of course that is a joke) The bays open as the cohesive wet slurry blanket is destabilized from beneath when it reaches the ground, w/ overpressure force of trapped airmass overcoming the cohesive force of the wet blanket. This model explains all of the many incredibly beautiful features observed in this confounded puzzle. I’ll try to make up some diagrams.

    In this model the sand falls from reentry and chills quickly in the upper troposphere while falling relatively slowly. In the lower troposphere it starts picking up water, some of which may freeze at first as sand kernel hail. Eventually it forms a cohesive blanket somewhere low in the troposphere when it picks up water that condenses onto the free fall chilled sand.

    As the slightly irregular thickness wet blanket nears the ground, those irregularities in thickness cause an unstable migration of the slurry within the layer to move downhill within the blanket toward the thicker parts of the blanket which hang lower at its bottom surface. As the blanket is reaching the ground, the trapped air domes eventually reach a pressure that ruptures the cohesive force of the blanket at the apex of the domes, much like soap bubbles burst at the top where it becomes the thinnest, due to gravity induced pooling at the bottom of the bubble.

    Sorry Mike, I used the bubble word!

    When the domes burst, they erupt at the top with a jet of trapped pressurized air. Upon bursting, the membrane recoils and the momentum throws the slurry toward the outside of each dome & down its sloping sides. Its like pouring hail out of a shovel at an angle off vertical into a pile. The horizontal momentum of the slurry makes it slide away from the shovel for a bit after its on the ground. Now imagine a thousand shovels around an ellipse doing that all at once. The destabilization thinning of the membrane is chaotic, with the bigger domes triggering higher and therefor trapping more air than those triggering lower. Some CBays slosh down and displace rims of other CBays. This feature of imprinting is clearly visible many places in the poster (and elsewhere naturally) where one bay has landed slightly after another and relocated part of the rim of the first one. The overlaid bay ‘sweeps out’ the area just inside its edges as the slurry ridge slides to a stop, removing the edges of other CBay that were under the second CBay upon landing.

    Careful examination of the imprinted structure shows that Bay Dome rupture and ground contact were roughly coincident during the process, but not identically so. There seems to be some variation on either side of coincident timing for those two stages of the process.

    There are many other emplaced or imprinted features of this mechanism in the poster which is what led me to land on the trapped air dome hypothesis as my preferred. All you have to do is get your head around the simple idea of a wet sand slurry blanket tens of thousands of square km big descending through the sky, (and dry sand rain falling all the way from reentry to form that blanket in the lower atmosphere, and a few other simple concepts) and you’re there!

    The problem with initiation of the CBays at higher levels of the atmosphere, or during exoatmospheric loft by displacement of steaming chunks of fragmented Ice Sheet in the ejecta for example, is that whatever structure you can conceive of, it has to stay stable and maintain shape all the way to landing/emplacement. And that is problematic for my limited imagination.

    The elongation of the bays is caused by stretching of the membrane along the in-track direction (relative to the blanket lay-down) which occurs when the blanket transitions from a sloping angle off of vertical to a nearly horizontal angle at the surface just before lay-down. This stretching of the wet sand blanket along its lay-down direction causes the dome burst process to open wider in-track than it does cross-track in proportion to the ratio of tensile (cohesive) stresses of the wet blanket membrane in those two directions. This stretching factor (or eccentricity as written Major/Minor axis lengths) is described as 1/Tan(theta) where theta is the angle of the descending wet blanket relative to horizontal. So CBay eccentricity relates directly to blanket descent angle off the horizontal.

    The trapped air domes bursting to form the CBays is a meteorological phenomenon. So tell your friends it really was the wind that made the Bays. What happens when we get impacts with an atmosphere in the mix? No big deal.

    Cosmic wind. Glass rain. Airborne sand blanket. Yeah, no problem. Basic stuff.

    When I finally had to admit that they were actually “bubbles”, I was embarrassed to have dismissed such a concept upon first exposure. But that is exactly where several days of intensive grey matter analog calculations have led me now, farther behind at work and courting catastrophists on the internet!
    In this model the sand falls from reentry and chills quickly in the upper troposphere while falling relatively slowly. In the lower troposphere it starts picking up water, some of which may freeze at first as sand kernel hail. Eventually it forms a cohesive blanket somewhere low in the troposphere.

    As the slightly irregular thickness wet blanket nears the ground, those irregularities in thickness cause an unstable migration of the slurry within the layer to move downhill within the blanket toward the thicker parts of the blanket which hang lower at its bottom surface. As the blanket is reaching the ground, the trapped air domes eventually reach a pressure that ruptures the cohesive force of the blanket at the apex of the domes, much like soap bubbles burst at the top where it becomes the thinnest, due to gravity induced pooling at the bottom of the bubble.

    Sorry Mike, I used the bubble word!

    when the domes burst, they erupt at the top with a jet of trapped pressurized air. Upon bursting, the membrane recoils and the momentum throws the slurry toward the outside of each dome & down its sloping sides. Its like pouring hail out of a shovel at an angle off vertical into a pile. The horizontal momentum of the slurry makes it slide away from the shovel for a bit after its on the ground. Now imagine a thousand shovels around an ellipse doing that all at once. The destabilization thinning of the membrane is chaotic, with the bigger domes triggering higher and therefor trapping more air than those triggering lower. Some CBays slosh down and displace rims of other CBays. This feature of imprinting is clearly visible many places in the poster where one bay has landed slightly after another and relocated part of the rim of the first one. The overlaid bay ‘sweeps out’ the area just inside its edges as the slurry ridge slides to a stop, removing the edges of other CBay that were under the second CBay upon landing.

    Careful examination of the imprinted structure shows that Bay Dome rupture and ground contact were roughly coincident during the process, but not identically so. There seems to be some variation on either side of coincident timing for those two stages of the process.

    There are many other emplaced or imprinted features of this mechanism in the poster which is what led me to land on the trapped air dome hypothesis as my preferred. All you have to do is get your head around the simple idea of a wet sand slurry blanket a couple of hundred thousand square km big descending through the sky, (and dry sand rain falling all the way from reentry to form that blanket in the lower atmosphere, and a few other simple concepts) and you’re there! The problem with initiation of the CBays at higher levels of the atmosphere, or during exoatmospheric loft by displacement of steaming chunks of fragmented Ice Sheet in the ejecta for example, is that whatever structure you can conceive of, it has to stay stable and maintain shape all the way to landing/emplacement. And that is problematic for my limited imagination.

    The elongation of the bays is caused by stretching of the membrane along the in-track direction (relative to the blanket lay-down) which occurs when the blanket transitions from a sloping angle off of vertical to a nearly horizontal angle at the surface just before lay-down. This stretching of the wet sand blanket along its lay-down direction causes the dome burst process to open wider in-track than it does cross-track in proportion to the ratio of tensile (cohesive) stresses in those two directions. This stretching factor (or eccentricity as written Major/Minor axis lengths) is described as Tan(theta) where theta is the angle of the descending wet blanket relative to horizontal.

    The trapped air domes bursting to form the CBays is a meteorological phenomenon. So tell your friends it really was the wind that did made the Bays.

    Cosmic wind. Glass rain. Airborne sand blanket. Yeah, no problem. Basic stuff.

    When I finally had to admit that they were actually “bubbles”, I was embarrassed to have dismissed such a concept upon first exposure. But that is exactly where several days of intensive grey matter analog calculations have led me now, farther behind at work and courting catastrophists on the internet!

  34. (revised second attempt)

    OK guys and gals. You are obviously a very good natured group for not ripping me a new one after that post. Appreciated. I’ve now had a long and informative lunch w/ Michael Davias. The poster is amazing! And now I am armed with some juicy shallow angle impact papers.

    Turns out the Carolina Bays are a meteorological phenomenon, as I explain below.

    George and Dennis, you guys are my heros. Dennis, I completely hear you on the “waaaaaaay too little heat for sustained plasma” call. I was realizing that as I wrote the Ball LIghtning paragraph at 2:45 am, too vested in the effort to give up at that point. The shallow impact is a relatively cold one with the majority of the ejecta jet reflecting from the surface and heading down range in a spray of somewhat less speed than it comes in at. Dominating mechanisms are oblique shock and shearing forces. Its actually good news because with less volume fraction of plasma if any, the ‘hot zone’ of the shallow impact should be easier to simplify w/ some basic assumptions.

    The situation for me is not good. I have no time to spare professionally, and yet I am compelled to write a shallow angle impact paper and have it reviewed by all my former professors and room mates who are now engineering PhDs. I’m ready to start with the impact characterization paper, then the trajectory analysis to describe the ascent and coast phases of the ejecta blanket, and finally a detailed analysis of the descent phase, culminating in blanket lay-down and CBay emplacement. I’ll even get another degree or two out of the deal if necessary. So who’s got the research money?

    “Characterization of the ‘hot zone’ in low angle hypervelocity impacts” I’m guessing that to assume

    1) dominant mechanisms are oblique shock and shearing forces, the entire bolide travels through and is transformed by the ‘hot zone’, and
    the energy of the collision may be calculated by the volume of crater (instead of just the mean diameter) which seems relevant since these seem to produce shallow craters,

    2) the energy of the collision may be calculated by the volume of crater (instead of just the mean diameter) which seems relevant since these seem to produce shallow craters,

    then some fancy curve matching may be used to describe the development and evolution of the hot zone and its characteristic shape. And here is the important part – it should be a non-dimentionalized treatment written as ratios of opposing influences, so the result is a parametric that allows ease of tweaking to match whatever case you are interested in. Its a mix of Thermodynamics and Engineering Mechanics so square in my area. I have to call my former fluids prof, the shock wave guru.

    Anyway Michael Davias seems right on the money with the foam spray on the ocean beach idea, which I immediately rejected upon hearing it the first time (sorry Mike!). The ocean is space w/ the bolide floating ashore and crashed by the waves. Shore is the Earth. The foam is the sand.

    The bubbles are the domes of sequestered atmosphere that became trapped under the wet sand blanket as it reached the ground, those domes bursting from overpressure from the weight and downward momentum of the wet sand blanket, depositing the slurry mix in the form of the emplaced CBays. Maybe some hail in there too, as that seems to helps the flow of the slurry to meet the observed characteristic flow of emplacement.

    How did Mike know that?

    I’ve already theorized a series of mechanisms to get the sand from impact to CBay emplacement, but I’ll let him fill you in with his own cognitive filter. Its pretty basic! (of course that is a joke) The bays open as the cohesive wet slurry blanket is destabilized from beneath when it reaches the ground, w/ overpressure force of trapped airmass overcoming the cohesive force of the wet blanket. This model explains all of the many incredibly beautiful features observed in this confounded puzzle. I’ll try to make up some diagrams.

    In this model the sand falls from reentry and chills quickly in the upper troposphere while falling relatively slowly. In the lower troposphere it starts picking up water, some of which may freeze at first as sand kernel hail. Eventually it forms a cohesive blanket somewhere low in the troposphere when it picks up water that condenses onto the free fall chilled sand.

    As the slightly irregular thickness wet blanket nears the ground, those irregularities in thickness cause an unstable migration of the slurry within the layer to move downhill within the blanket toward the thicker parts of the blanket which hang lower at its bottom surface. As the blanket is reaching the ground, the trapped air domes eventually reach a pressure that ruptures the cohesive force of the blanket at the apex of the domes, much like soap bubbles burst at the top where it becomes the thinnest, due to gravity induced pooling at the bottom of the bubble.

    Sorry Mike, I used the bubble word!

    When the domes burst, they erupt at the top with a jet of trapped pressurized air. Upon bursting, the membrane recoils and the momentum throws the slurry toward the outside of each dome & down its sloping sides. Its like pouring hail out of a shovel at an angle off vertical into a pile. The horizontal momentum of the slurry makes it slide away from the shovel for a bit after its on the ground. Now imagine a thousand shovels around an ellipse doing that all at once. The destabilization thinning of the membrane is chaotic, with the bigger domes triggering higher and therefor trapping more air than those triggering lower. Some CBays slosh down and displace rims of other CBays. This feature of imprinting is clearly visible many places in the poster (and elsewhere naturally) where one bay has landed slightly after another and relocated part of the rim of the first one. The overlaid bay ‘sweeps out’ the area just inside its edges as the slurry ridge slides to a stop, removing the edges of other CBay that were under the second CBay upon landing.

    Careful examination of the imprinted structure shows that Bay Dome rupture and ground contact were roughly coincident during the process, but not identically so. There seems to be some variation on either side of coincident timing for those two stages of the process.

    There are many other emplaced or imprinted features of this mechanism in the poster which is what led me to land on the trapped air dome hypothesis as my preferred. All you have to do is get your head around the simple idea of a wet sand slurry blanket tens of thousands of square km big descending through the sky, (and dry sand rain falling all the way from reentry to form that blanket in the lower atmosphere, and a few other simple concepts) and you’re there!

    The problem with initiation of the CBays at higher levels of the atmosphere, or during exoatmospheric loft by displacement of steaming chunks of fragmented Ice Sheet in the ejecta for example, is that whatever structure you can conceive of, it has to stay stable and maintain shape all the way to landing/emplacement. And that is problematic for my limited imagination.

    The elongation of the bays is caused by stretching of the membrane along the in-track direction (relative to the blanket lay-down) which occurs when the blanket transitions from a sloping angle off of vertical to a nearly horizontal angle at the surface just before lay-down. This stretching of the wet sand blanket along its lay-down direction causes the dome burst process to open wider in-track than it does cross-track in proportion to the ratio of tensile (cohesive) stresses of the wet blanket membrane in those two directions. This stretching factor (or eccentricity as written Major/Minor axis lengths) is described as 1/Tan(theta) where theta is the angle of the descending wet blanket relative to horizontal. So CBay eccentricity relates directly to blanket descent angle off the horizontal.

    The trapped air domes bursting to form the CBays is a meteorological phenomenon. So tell your friends it really was the wind that made the Bays. What happens when we get impacts with an atmosphere in the mix? No big deal.

    Cosmic wind. Glass rain. Airborne sand blanket. Yeah, no problem. Basic stuff.

    When I finally had to admit that they were actually “bubbles”, I was embarrassed to have dismissed such a concept upon first exposure. But that is exactly where several days of intensive grey matter analog calculations have led me now, farther behind at work and courting catastrophists on the internet!

    Thomas Harris
    Brooklyn NY USA

  35. Greetings:

    Allow me to briefly comment on Time Harris’s input. He has come at the challenges of the CBs with a fresh and insightful perspective. I am indebted to him for putting forth what may (finally!) be a viable mechanism for the distribution and emplacement of the sandy ejecta blanket, while generating the bay landforms in proper orientation and shape. He is the real deal and a nice fella also.

    – Michael

  36. I’m not clear how it fits with Mr. Davias’s hypothesis. But one thing I don’t hear anyone considering yet is the idea of a cluster airburst event, even though it is proposed in the Lake Cuitzeo paper. And yet when you think it through, the idea represents a major paradigm shift away from the standard model idea of one at a time, single bolide, impact events. If fact, it represents a completely different impact mechanism from anything that’s ever been modeled, or studied before.

    Bill Napier pointed out in Palaeolithic extinctions and the Taurid Complex that the breakup of comets is now recognized as a common path to their destruction. And most of the folks I’m reading still point to the ‘string of pearls’ that was SL-9 before it impacted Jupiter as their preferred model of a typical breakup mechanism. But I’m thinking that SL-9 does not represent a typical breakup of a comet at all. And certainly not a kind of breakup mechanism that the inner planets have to worry about. 

    Most of the astronomical data indicates that SL-9 was broken into a string of fragments by tidal forces in a close pass of Jupiter before returning to impact; sort of like something pouring over an edge into a stream of drops or fragments. So a breakup that produces a long string of fragments like that requires that the comet make a close passage of a very powerful gravity well.

    But in fact SL-9 does not represent the most common breakup mechanism at all. It’s just the only time we’ve ever witnessed a broken comet hit a planet. So it’s the first one that comes to mind. The other, probably far more common breakup mechanism is represented by objects like comets Linear-1, SW-3, and 17P/Holmes; all of which broke up apparently spontaneously. And without the influence of any nearby planet. It’s as if the ices holding them together sublimated in the warmth of the sun and they just ‘came unglued’ like the wings of Icarus.

    If a dense cluster of comet fragments such as we see in the images of Linear, or SW-3 were to hit soon after the complete breakup of a large comet, then you’d see a different kind of impact mechanism from anything anyone has ever imagined before. Instead of single bolides coming in one at a time, plop, plop, plop. You’d get something like a giant shotgun blast, or 10,000 Tunguska class airbursts hitting a concentrated area within a matter of seconds. Only the very first fragments on the leading edge of the cluster would hit cold atmosphere. The rest of the cluster would be falling into the already superheated impact plumes of those that lead the way. And they’d just crank up the heat, and pressure.

    I wonder what something like that would do to the ground, or an ice sheet.

  37. Tom, Dennis,
    would Saginaw Bay impact ejecta on sub-orbital trajectory at re-entry time have been fast enough for plasma to form at high altitude ? Effects of plasma conditions could transform ejecta prior to cool-down in mid atmosphere and ground level impact? Tell it like it is, Tom!

  38. I haven’t got an answer for that one Hermann. I’ve read quite a few folks talking about ice sheet impacts, and theorizing what the effects might be. I’ve studied a lot of Pete Schultz’s work at the HVGR. And I’ve got my own radical ideas of what happened to the ice sheet back then. But so far I haven’t seen any actual numerical modeling that scales an ice sheet impact up to the kind of multiple fragment cluster event we’re talking about, and takes the hydrothermal explosive potential into the equation.

    How much those hydrothermal explosive forces contribute to overall processes of an ice sheet impact are only a small part of the unanswered questions about the points of impact. So the question of how much energy was available to launch that ejecta in the first place remains undefined, much less answered.

    And if anyone knows of peer reviewed work the addresses how large fragments of ice can be expected to behave on re-entry after a sub orbital flight I’d sure like to read it.

  39. Dennis,
    from Saginaw Bay Center @ 43.84 N, 83.66 W, we may calculate the minimmum impact velocity v:

    v=10.8 km/sec to Lumberton, NC @ 34.63 N, 79.01 W
    v=14.6 km/sec to Tallahassee, FL @ 30.45 N, 84.27 W

    Here, we are gnoring curvature of Earth, diminishing gravity w/altitude, air resistance at top of atmosphere, so impact velocity = initial ejecta velocity.

    Actually went 44 miles East of Tallahassee so get simpler formula
    at constant longitude:
    distance = 6366 k x Delta phi, if latitudes agree.
    where Delta phi = difference of latitudes.

    At 45 deg ejection angle, velocity = g x distance, g=9.81 km/sec^2. The distance traveled is determined by ejecta falling back to Earth, the time for this is inversely proportional to g=9.81,
    t = sqr(2) v/g:

    t = 2 min 38 sec to Lumberton, NC
    t = 3 min 35 sec to Tallahassee, FL (44 miles E)

    [I used to teach calculus, so there is hope that these are the correct results.]

    DOES THAT HELP to decide on plasma forming??

  40. I am afraid, but I also have hope.

    There was probably not enough energy at the collision site to launch any big chunks exoatmospheric. This is true because:

    First, the ice is brittle compared to rock or hypersonic shock waves, so it shatters extensively near the blast. Likely nothing near enough to the blast to get lofted that far was very big. Likewise, nothing very big got lofted very far. Probably not even off the Ice Sheet itself, since the energy was absorbed by extensive fracture (farther out) and steam conversion (closer in). The vast majority of the impactor went down range, based on the butterfly pattern and implied shallow angle of same. These shallow impacts are very low energy in terms of heat release relative to steep angle where all the kinetic is converted to heat. This is a relatively cold impact relative to speed and size of impactor.

    And, It would seem that lots of ice got lofted, but it was all churned extensively through the “hot zone” to bring it up to an exoatmospheric loft. But lets remember our atmospheric profile for Earth…

    So I’m afraid no big ice chunks made it up that high. I’m also afraid there was no plasma at the initial blast based on some impact hydrocode analysis which I’m pretty sure I read (and didn’t just dream) although this all nigher binder is starting to play tricks on my mind. But I have hope…

    The plasma is already there in the form of our friendly yet rarefied ionosphere. The water that got up there probably didn’t last too long being already energized by the blast (no longer ice, although as a vapor it may have frozen quickly upon the rapid pressure and temperature drop on the way up). water vapor or even water ice clouds are unwelcome visitors in space. Any remaining chunks would most likely vanish upon reentering. This is especially true when the ionosphere was being heated in bulk by a few hundred cubic miles of re-entering high density sand. Lots of heat exchange going on in that process, but any ice or water vapor is the loser for that fact.

    The ionospheric heating of that much sand reentering would have been spread over so much area that the view factor would likely have made the sky seem hot to the shoulders of anyone standing on the surface underneath. Time to put on the rain gear… The upper atmosphere would have bulged from the thermal expansion. The light alone from the reentering sand would be very intense over such a large area. Imagine the house fire across the street ignighting your window curtains from the IR flux. Common occurrence.

    The sand has a low ballistic coefficient and slows down quickly during reentry, perhaps melting, but I see it staying solid and just highly warmed by reentry (?) since this is easier to conceptualize. We can go through that exercise based on kenetic release upon decel, drag vs ballistic coefficient, duration of decel, heat of melt for the sand, etc, but lets save that exercise for the moment (!).

    upon arrival in the extremely cold layers of upper atmosphere, the very dry sand then falls relatively slowly with low ballistic coefficient and has lots of time to chill. Its dry due to vacuum, ionospheric plasma bombardment, and reentry. Tough to get much dryer. Sand arriving later in the party over any given ground point, from higher loft angles (longer flight time for the same distance along the ground) would be falling through warmer air after the earlier sand dumped heat there, but this is likely confined to the upper layers, because it is soooo cold up there. The higher loft angles are produced earlier on in the crater forming process when the material being ejected is coming from a hotter push, for what that’s worth. Lots of time through top of arc to view cold space hemisphere above and chill before reentry.

    then it falls relatively slowly for a long time, again which we can figure with some basic assumptions. But this atmospheric descent phase has two other effects. The Earth is no longer rotating underneath it because its out of space and back in the atmosphere now so don’t use the rotating Earth term for this phase of sand transport analysis. And the winds aloft may be significant (as in jet stream) and even more so than today because weather may have been windier w/ Ice Sheet induced gradients as forcing function. Slowly falling sand would be subject to downwind drift. No ballistic descent to surface, no durations to reflect same. Ballistic only to top of atmosphere and then a relatively long drift phase.

    The weather could have been very calm though, as any instinctive Catastrophist will know by intuition, because the worst catastrophes happen in the best weather.

    I have now completed my 2 week undergraduate degree on the CBays, leaving ball lightning behind in my first semester.

    The atmosphere messes up any attempt to backtrack from the ground to the primary impact. The answer is to model the crater to estimate a conservatively bounded set of launch conditions. Then determine what the altitude profile, and therefore the environmental profile would be. This can give us better ideas on what would go on during exoatmospheric loft for both sand and any other material in question such as missing parts of Saginaw, all those clovis arrowheads I can’t seem to fine (joke, I know wrong epoch), and the Bay City Rollers which I so desperately miss.

    My current 2 week degree is on shallow angle crater science. I have read some papers and have some more to read. The modified Maxwell Z model from
    “Experimental ejection angles for oblique impacts: Implications for the subsurface flow-field” submitted ’03 published ’04, by Jennifer L. B. ANDERSON, Peter H. SCHULTZ, and James T. HEINECK
    is empirically derived from lots of measured craters and has good predictive ability but still needs further development for shallow angle cases. They used a laser velocimetry technique to actually measure what came out of the crater as a function of time during the excavation process. Impressive automated data acquisition. Could have used one of those rigs over Saginaw Bay a while back.

    I have written to Anderson (and will also forward to Shultz and Heineck) regarding to possibility of using the beautifully laid out butterfly crater on Mars instead of the (expensive to set up and run) laser velocimetry to try to validate a shallow angle mod to Maxwell Z model. I even suggested some concepts for such modification. Fingers crossed. Maxwell Z is a cool model. Empirically derived excavation formula.

    The butterfly crater on Mars is actually a PAIR of twin-lobed craters perhaps created by a de orbiting moonlet. Unfortunately the paper that postulates how they got there has some serious issues IMHO so I brought these and many other ideas up in the outreach to Anderson. Because of some stuff they didn’t address, the butterfly crater set may actually be the perfect acid test for a gutsy shallow angle impact analytic. Sweeeeeet. Thats even better than a really elegant automated data acquisition.

    Tim H

  41. Here, we are ignoring curvature of Earth, diminishing gravity w/altitude, air resistance at top of atmosphere, so impact velocity = initial ejecta velocity.

    Also ignored rotation of planet Earth about polar axis, which Michael takes care off in elegant fashion.

  42. Tom,
    There was probably not enough energy at the collision site to launch any big chunks exoatmospheric.

    My above computation is based on the empirical fact that large amounts of material were lofted to the Carolinas and indeed as far as Florida if the hundreds of bays were all formed within seconds or at most minutes.

    The physics implies that there were minimal velocity upward of 10 km/sec (my calculation).

    Kinetic energy:
    E_k = 1/2 * mass * velocity^2.

    Lots of energy implied, large velocity v>10km/sec, and large mass of lofted stuff, hence large E_k???

  43. Many thanks Hermann,

    If the impact zone weren’t an ice sheet then the problem would be far less complex.

    As you point out, it’s not hard to postulate enough kinetic energy in a very large impact event to get material ejected into sub-orbital, orbital, perhaps even escape velocities. And on re-entry yes, we should expect significant thermal plasmas to form along the re-entry paths. That much is a given. But then, if the ejected material was water ice, how does H20 behave at such temps?

    The questions that stick in my mind are what happens when you suddenly heat a few thousand cubic miles of ice enough that it doesn’t just flash to steam, but disassociates into hydrogen, and oxygen, which is then heated even more until the electrons become stripped from their nuclei, and you have a dense, high energy thermal plasma? How much of the resulting incandescent hydrogen, and oxygen, actually become electrically conductive plasmas? Do we get enough superconducting plasma in the impact plumes, and re-entry paths to provide short circuits between the ionosphere and the ground?

    If so, how quickly does the plasma loose energy to infrared radiation until it’s no longer electrically conductive? What are the ground effects of that IR pulse? And as it cools back down to a non-conductive incandescent state, and finally to normal terrestrial temps, does the hydrogen, and oxygen, recombine to become H2O again?

    And finally, of the thousands of cubic miles of ice that only flashes to steam in the atmosphere without becoming incandescent, how long does it take for it to precipitate back out as rain, and snow?

  44. I’m not clear how it fits with Mr. Davias’s hypothesis. But one thing I don’t hear anyone considering yet is the idea of a cluster airburst event, even though it is proposed in the Lake Cuitzeo paper. And yet when you think it through, the idea represents a major paradigm shift away from the standard model idea of one at a time, single bolide, impact events. If fact, it represents a completely different impact mechanism from anything that’s ever been modeled, or studied before.

    Bill Napier pointed out in Palaeolithic extinctions and the Taurid Complex that the breakup of comets is now recognized as a common path to their destruction. And most of the folks I’m reading still point to the ‘string of pearls’ that was SL-9 before it impacted Jupiter as their preferred model of a typical breakup mechanism. But I’m thinking that SL-9 does not represent a typical breakup of a comet at all. And certainly not a kind of breakup mechanism that the inner planets have to worry about.

    Most of the astronomical data indicates that SL-9 was broken into a string of fragments by tidal forces in a close pass of Jupiter before returning to impact; sort of like something pouring over an edge into a stream of drops or fragments. So a breakup that produces a long string of fragments like that requires that the comet make a close passage of a very powerful gravity well.

    But in fact SL-9 does not represent the most common breakup mechanism at all. It’s just the only time we’ve ever witnessed a broken comet hit a planet. So it’s the first one that comes to mind. The other, probably far more common breakup mechanism is represented by objects like comets Linear-1, SW-3, and 17P/Holmes; all of which broke up apparently spontaneously. And without the influence of any nearby planet. It’s as if the ices holding them together sublimated in the warmth of the sun and they just ‘came unglued’ like the wings of Icarus.

    If a dense cluster of comet fragments such as we see in the images of Linear, or SW-3 were to hit soon after the complete breakup of a large comet, then you’d see a different kind of impact mechanism from anything anyone has ever imagined before. Instead of single bolides coming in one at a time, plop, plop, plop. You’d get something like a giant shotgun blast, or 10,000 Tunguska class airbursts hitting a concentrated area within a matter of seconds. Only the very first fragments on the leading edge of the cluster would hit cold atmosphere. The rest of the cluster would be falling into the already superheated impact plumes of those that lead the way. And they’d just crank up the heat, and pressure.

    I wonder what something like that would do to the ground, or an ice sheet. But I’m prttey sure it’s not a ballistic/kinetic impact crater

  45. here is a reference that gives some good cratering intel for the case w/o atmosphere using the Deep Impact NASA mission results where the thing getting hit is the comet for a change. This is really juicy for our effort since we learn about the comet properties and also about impact science at the same time. It was actually written FOR US if you think about it.

    http://www.eas.purdue.edu/richardson/DIplumeballistics.html

    The abstract alone is a beautiful discourse on what forces are in play as this event evolves after impact. Note low density estimate. And naturally we like Fig. 6: “The Maxwell Z-model of excavation flow”, because its the Maxwell Z-model!

    Bulk density of only 400 kg/m^3! Even with a wide error spread on that number, its looooooow.

    Abstract:

    In July of 2005, the Deep Impact mission collided a 366 kg impactor with the nucleus of Comet 9P/Tempel 1, at a closing speed of 10.2 km sec^-1. In this work, we develop a first-order, three-dimensional, forward model of the ejecta plume behavior resulting from this cratering event, and then adjust the model parameters to match the flyby-spacecraft observations of the actual ejecta plume, image by image. This modeling exercise indicates Deep Impact to have been a reasonably “well-behaved” oblique impact, in which the impactor-spacecraft apparently struck a small, westward-facing slope of roughly 1/3-1/2 the size of the final crater produced (determined from initial ejecta plume geometry), and possessing an effective strength of not more than Y = 1-10 kPa. The resulting ejecta plume followed well-established scaling relationships for cratering in a medium-to-high porosity target, consistent with a transient crater of not more than 85-140 m diameter, formed in not more than 250-550 sec, for the case of Y = 0 Pa (gravity-dominated cratering); and not less than 22-26 m diameter, formed in not less than 1-3 sec, for the case of Y = 10 kPa (strength-dominated cratering). At Y = 0 Pa, an upper limit to the total ejected mass of 1.8 x 10^7 kg (1.5-2.2 x 10^7 kg) is consistent with measurements made via long-range remote sensing, after taking into account that 80% of this mass would have stayed close to the surface and then landed within 45 minutes of the impact. However, at Y = 10 kPa, a lower limit to the total ejected mass of 2.3 x 10^5 kg (1.5-2.9 x 10^5 kg) is also consistent with these measurements. The expansion rate of the ejecta plume imaged during the look-back phase of observations leads to an estimate of the comet’s mean surface gravity of g = 0.34 mm sec^-2 (0.17-0.90 mm sec^-2), which corresponds to a comet mass of m_t = 4.5 x 10^13 kg (2.3-12.0 x 10^13 kg) and a bulk density of rho_t = 400 kg m^-3 (200-1000 kg m^-3), where the large high-end error is due to uncertainties in the magnitude of coma gas pressure effects on the ejecta particles in flight.

  46. Dennis
    “Do we get enough superconducting plasma in the impact plumes, and re-entry paths to provide short circuits between the ionosphere and the ground?”

    Yes, and it melts lots of surface rock in N. Minnesota! (I’m just kidding, maybe)

    So I think your are conceptualizing far too highly energetic an event due to the shallow angle involved, for a couple of reasons. Most of the kinetic E is carried down range in the ejecta jet, some of which is still above escape V for whatever its headed relative to the Sun and Earth’s orbital vector about same at the moment. Look at Butterfly Crater on Mars at the lateral ejecta pattern. Thats where the Bays came from. The other 90% (total guess) jets out down range at a flatter angle than it came in on mostly.

    There is probably some lateral dispersion of that jet, as implied by the trend of lower angle cases from 30 to 15 degrees. I think this exit jet lateral dispersion process gets more chaotic as the impact gets flatter and the forcing function of imparted momentum upon the impactor by the target surface becomes less well defined. This is for two reasons. sum of vertical forces is much lower for shallow angle, & more spreading out across the surface both mean lower peak stress (force/area) and (key) the energetic mixing, or hot zone, is spread out so peak temps are much lower. For shallow angle he energy doesn’t excavate so much, (butterfly crater is very shallow for its size) but reflects with vertical damping from some heat loss and from later spreading – from the lateral pressure distribution profile during the impact being highest in the mid line and imparting a laterally dispersive impulse while the hot zone exists. Stretched out hot zone in-track gives more time for establishing laterally dispersive flow field in the jet.

    visualize a Maxwell Z-model translating with the impactor as it spreads out comet into a hot zone. That hot zone imparts outward momentum to the surface which then evolves into a crater after the pulverized comet jet leaves the station, taking away with it the majority of its most dangerous elements, kinetic energy and the heat of its one transformation from solid to slurry (not so great since density and strength are generally proportional)

    The beauty for us all on this forum is that those insane comet storms are perfectly staged after this impact by the non-escape, slower portion of the down range ejecta jet that could literally be going anywhere after the chaos of this process, and what with the moon up there to stir things up too, so now I believe in the comet storm even more than I did when the ablative scarring made me a believer upon watching the Sandia attached vortex video to begin my insane spiral into this completely interrelated jumble of what are actually perfectly organized parts of a single bigger picture.

    Is that clear!?!

    I’ve come to a remarkable enlightenment over the last few weeks during CBays undergraduate, and now in my more advanced and more mechanically founded conceptualizations of this crazy business. During this very brief period I have suddenly come to better understand everything I’ve EVER learned in life from cultural anthropology to perturbational orbital mechanics, from skydiving to sailing, how all of those things are related, and all of this because I paused to contemplate the enigmatic CBays. I understand more about where my instincts come from, and so too how to make better use of them going forward. Stop and study the imprint. Maintain situational awareness on all scales.

    Embrace all science. CLEARLY the CBays are imprinted Bolide Ignimbrite. The Cosmic and the Terra are as one.

    Enigmatic CBays. Imprint of a ET event most likely in the form of an initial but grazing comet strike that led to multiple comet storms around the world for some time after, as the various orbiting clusters of rechilled comet slurry jet proceeded to be flung around by the Earth-Moon system over many months or years until being cleaned out of that space by those two bodies or flung back into a different helio orbit by them. this is Masters and PHD papers for many years to come, with all of the possible scenarios that need investigating as a result of the initial event that deposited the CBays.

    I largely blame Michael Davias for this insane state I’m now left in, but everyone who posts on this forum is also guilty to some degree of my present catatonic state of shock, Mr. Howard and Mr. Cox most notably. When are we having lunch guys? You have to explain to my wife how you make me like this. Please. Come to Brooklyn.

    In the case of the ever shallower approach angle, less and less energy is delivered to the site of the impact, with more and more being carried away within the exiting jet. And its not just kinetic being carried away. the impactor also carries the heat of its own destruction with it in the exiting jet. Sweet.

    This way humans live to talk about it and make art to record it afterward, because we as a species are smarter than your average algae or mosquito. We have survived this rather harsh bit of punctuation in the otherwise gradual process of natural selection in this biosphere. Actually we as a species are the imprint of the evolutionary biological process on that biosphere. The living imprint. We must take it as a lesson to maintain situational awareness on all scales, and study the geological record to find the truth imprinted within. Sometimes catastrophic truth. With an open mind, right George? I have never met or even talked to you my friend, but I love you.

    Now we have lots of work to do to continue to prove the scenario took place. And to figure out comet mitigation or even reclamation. George there is your next enterprise, to follow naturally from your current one.

    I just wonder how many times it did take place. That should fall out of some good shallow angle impact science and the perturbational orbital dynamics that the impact model can feed, to trace exit jet volume through the Earth-Moon orbital environment and find solutions to known comet storm sites. No problem.

    TH

    Dennis
    “It’s as if the ices holding them together sublimated in the warmth of the sun and they just ‘came unglued’ like the wings of Icarus.”
    Bingo

    and thats also the key to determining their age. I’m guessing the average density of the overall comet mass of our solar system constantly decreases as bigger chunks break to smaller one in the fractalated Oort cloud or wherever these things ultimately came from. Star farts.

  47. Dennis,
    “And finally, of the thousands of cubic miles of ice that only flashes to steam in the atmosphere without becoming incandescent, how long does it take for it to precipitate back out as rain, and snow?”
    most likely 40 days and 40 nights.

  48. Thanks Tom,

    While you’re still thinking about the kinetic impact of solid objects, I’m not. I’m looking at a cluster airburst scenario where almost 100% of the kinetic energy of a very large, and dense cluster, approximately 200 miles wide, of small cometary fragments coming in at a shallow angle of about 30 degrees is translated to heat in atmosphere. The violence at ground level gets magnified compared to a crater producing kinetic impact. But it’s not characterized by shock metamorphic effects.

    I’ll go along with most of what you’re saying, except for this:

    “In the case of the ever shallower approach angle, less and less energy is delivered to the site of the impact, with more and more being carried away within the exiting jet. And its not just kinetic being carried away. the impactor also carries the heat of its own destruction with it in the exiting jet.”

    In fact, none of the violence exits, or gets “carried away” in an oblique airburst, or impact. It’s simply continues moving downrange.

    And yes, in point of fact, I am postulating a far more energetic event than anyone has ever imagined. And I think I’ll eventually be able to confirm planetary scarring to back it up. Those scars do not consist of craters, or anything anyone has ever imagined might be related to an impact event.

  49. Dennis,
    the CB impactor carved out Saginaw Bay, fairly concentrated. Hence, the comet debris cluster that you postulate was dispersed before impact but not too much. If Michael collects all his data, can he figure the total mass of ejecta contained in CBs? Then, using my velocity calculation, he should be able to calculate the total energy of the impact, a lower bound, because we don’t know how much was used up on ground zero melting, crushing ice maybe even rock. Duncan Steel in his books has details on impact energies. But we still don’t seem to know much about comet cores, my suspicion is still that there were metal condensation cores (average density of overall comets is known to be quite low, however). If so, Saginaw Bay may have been the result of core impact alone, with the debris field much larger. Did Napier publish details of how to calculate the thermal radiation field of his hypothetical debris stream impact? If we knew his formulas then we could figure out if the re-entry ice/water/gravel masses dissociated the H2O.

  50. After studying Pete Shultz’s hypervelocity ice sheet impact experiments at NASA Ames, I remain skeptical that anything but a very large bolide could have penetrated the ice sheet to leave a recognizable crater in the sub ice surface in the region of Saginaw Bay. It’s difficult to envision heat penetrating a mile of ice to the sub ice surface, much less with enough remaining kinetic energy for shock metamorphism, and excavation of that surface to occur.

    And like reactive armor on a battle tank, the more oblique the angle of impact, the more protective we can expect the ice sheet to be of the sub ice surface. I need to see data from datable cores from the structure before I’m convinced.

    And so far I haven’t read where anyone has included the potential for hydrothermal explosive forces in their calculations of the energies of an ice sheet impact. All the calculations I’ve seen are as if the impact were into a relatively inert surface like rock, or soils.

    As far as the debris streams Napier describes,I don’t think anyone has done any modeling of the expected impact characteristics yet. Napier seems to be content to concentrate on the astronomy of the event, leaving the actual impact physics to planetary scientists to work out. And even though the YDB team proposed cluster airburst events, and we have numerous images of such clusters in short period orbits that cross those of all the planets of the inner solar system, to the best of my knowledge the impact community are still focused on assuming single bolide cratering events.

    Note that the rallying cry of skeptics to the YDIH remains, “Where’s the crater?”

    I guess they’re afraid to take that monster out of the closet, and confront it. Because if cluster events from things like Linear, or SW-3 are possible, then decades of work estimating the ages of surfaces on the Moon, and Mars, by counting the number of small craters goes right out the window.

  51. Yes I understand the looks of that air burst plume in the Sandia imagery, and how it eventually slows and starts arcing concave upward form convection once most or all of its incoming momentum is arrested, and the more violent cases are the ones interrupted by the ground before they slow and start to loft. Nasty business what happens at the surface, and then in the atmosphere as a result.

    The stuff that hit Earth may have hit the moon on the way in too. so plume from that kind of earlier event may be what come in toward Earth. Either way we want a shallow impact model because of the observed butterfly imprint on Earth. If the Earth entry velocities turn out to be like a drop from the Moon, then we can look for impact evidence there and guess what angle impact to characterize what plume may fall from Moon to Earth. Situational awareness.

    Meanwhile

    The the air burst cluster width may perhaps be correlated to the spread in the shallow angle impact jet over Saginaw. From some highly elliptic Geo-lunocentric orbit. As a generic shallow angle impact model is developed we can investigate the parameters that may be relevant to the first collision and eventually we will figure what happened to the Ice Sheet upon contact. Meanwhile the generic model will give us hints about what rains down after skipping the first time.

    Its not one big piece. Its lots of droplets from the exit jet that don’t make it out far enough to fall back toward the Sun. The irregular elements of the chaotic jet make up droplet streams with similar orbital injection parameters, per group, relative to Earth/Moon or Heliocentric coordinates. So when this first shot comes in at shallow angle, what you get is a whole bunch of droplet streams fired out into different directions relative to Earth and Moon and Sun, etc, so all different families of trajectories, some Earth captured, some Earth escape back to Heliocentric, some sub orbital, all depending on what you put in the front end of the initial impact in the model.

    The suborbital stuff is going to spread out for a few hundred to several hundred/few thousand before intersecting the atmosphere on the far side of the globe, possibly nearly all the way around more or less, which takes maybe 70 or 80 minutes or something. So depending on how you play with the input parameters to play with that output jet, you can send a cluster of comet droplets over a majority of the surface of the earth, with the farthest flying ones the most damaging and the shorter range ones not packing so much velocity.

    So I need to get back with the crater and shock wave camp for a spell, with this in closing

    Unified theory of Comet Catastrophism:

    Comet stuff floats in a cloud on the edge of the heliosphere in various states of disorganization. It is held there in a quasi stable balance of very weak solar wind pressure (by itself unsteady in nature), weak gravitational attraction to each other and to the nuclear plasma furnace at the approximate center of the whole conglomeration.

    Much of that Oort cloud may have insufficient angular momentum to actually be considered as heliocentric, and the outward flux of solar wind is unsteady enough to push the more static ones to higher angles of inclination relative to the ecliptic spontaneously, incase anybody wondered how that might be possible.

    They occasionally pass each other and exchange some momentum in the process, so one gets dropped toward the sun while the other is nudged farther out, perhaps even beyond the heliopause and on to escape the Suns pull forever. Conservation should be our practice….

    The stuff that drops toward the sun rains down into lower energy levels of the solar gravity well. It is gassy as it warms up and makes its own perturbations with respect to the stability of any long term parking orbit (in other words no such thing), as well as being perturbed by the planets or whatever other bodies are nearby, and eventually may impact one of those (planetary) gravity well hard points along the way down the Sun’s bigger well. And yes the gas giants are also considered hard points when encountered at cometary velocity.

    Sometimes when it rains down it splashes w/ some drops absorbed and and some drops continuing down the well as more rain, but starting at a lower velocity.

    As they are near the sun they bake out and get lighter and weaker, which can make them fragment spontaneously. A close encounter w/ whatever gravity well may have similar effect but is more dangerous because it generates higher density parts. The least threatening are the lowest density. They do tend to lose density faster as a group when the group is made of more smaller pieces w/ more presented surface area for that process.

    If various perturbations or impacts slow it enough, it may fall into the sun. Comets have survived passes within a million miles of the sun, much to the surprise of astronomers. But we as Catastrophists know anything is possible. Its probability that we find more interesting. WHen they do eventually cook over completely to vapor or plasma, the solar wind carries the effluent right back to where it started to repeat from the beginning.

    Self sustaining process, so don’t expect any significant break in that weather pattern over the next major fraction of the Sun’s life span…

    Unified theory of Terrestrial Comet Catastrophism, or corollary to the general theory:

    When the comet rain stuff falls into the Earth/Moon system, it gets flung all around the well by the convoluted and angularly energized topography of that well and bounces, splashes, squirts and sprays all over the place without mercy of what life it may extinguish in that process. Or seed.

    Eventually the rotating pair of planetary bodies here in our hood either fling the stuff out or our local portion of the well and downhill into the Sun’s deeper well, or it falls deep into our well where Earth can chomp it up into part of the biosphere called the water table, otherwise known as the integral geological imprint of comet stuff rain here on Earth throughout the history of our planet, or at least as long as there has been a water table. And again, as in the first case, and in fact as a subset of the first case, the long term predict for our neighborhood is for steady rain.

    TH

  52. Since the YDB team has included the Taurid Complex as the astronomical model for the Younger Dryas Impact Hypothesis in the Lake Cuitzeo paper, then the whole coherent catastrophism paradigm Clube & Napier have been talking about since they first published ‘The Cosmic Serpent’ in 1982, and then ‘The Cosmic Winter’  in 1990, has become a fundamental part of the postulate. So the origin and frequency of the catastrophic comets that’ve been coming our way are fairly well described.

    Have you read either of those books? Or Paleolithic extinctions, and the Taurid Complex? Napier, (2010) Or The Structure, and evolution of the Taurid Complex? D.I. Steel et. al. (1991)

    I said, while I am convinced that the CBs all formed at the same time, and are related to a previously unstudied kind of impact event. I remain to be convinced that Saginaw Bay is in fact a Pleistocene impact structure.

  53. TH –

    Great comment on May 27th. Somehow it never seemed to show up on my CT till now. I check every day almost, and hadn’t seen anything new for about 2 weeks.

    Anyway, specific feedback:

    You hit the nail on the head about modeling at Sandia, to create a matrix for different bursts – angles, sizes, altitudes, and impactor density, too.

    Also, to begin learning what happens underneath an ice sheet impact – whether an actual impact or an air burst (though an air burst does not seem possible with the CBs).

    Not from suborbital exo-atmospheric unless they are very small compared to the size of the Bays themselves…. Now if they were smaller or soft, different story.

    First of all, NOTHING ELSE explains the CBs. I argue (from an almost infinitely smaller experience base) that they HAD to be softer AND smaller. Hard = ‘normal’ craters. And “very small compared to the size of the Bays themselves” – yes. I agree with the exo-atmospheric and suborbital, too. As a fellow engineer (mechanical), I think from experience we grow capable of picturing mechanisms step-by-step, and what you say fits well with what some of us here are imaging in our heads, even if some (me in particular) don’t have the capacity to model it mathematically.

    Steam shredding everything to the same (small) grain size doesn’t sound far off. But if steam shredded something to make the sand at the ET impact site, how did it get to the CB sites? What’s the vehicle?

    Lots in this passage. Absolutely, to the shredding, in my thinking. And yes, as to what transported the sand to the CBs. But don’t forget that the sand is not ONLY inside the CBs. The sand appears to have been laid down draped over entire areas, including the rims of the CBs. I envision a mixed bag of sizes of ejecta, from you icebergs down to that sand. From the only data I’ve found (on Mt St Helens), the larger stuff was not transported so far away. But after the >1cm particles the smaller stuff seems to have spread all the way from 300 to 700 km away. Does this hold for impacts? I don’t have Sandia at my disposal.

    The powerful steam explosion on/in/especially UNDER the ice sheet is of critical importance, not just for it’s ability to shred and pulverize whatever is in the area, be it locally resident or astronomically delivered. Most of all for the potential to loft chunks of ice sheet while embedding whatever it feels like into that ice. Supernova titanium or Michigan sand. And steam isn’t all. Check your steam tables for the 100,000 degree range. Pretty sure its plasma. Plasma, plasma, plasma. Mmmmmm….

    Certainly plasma. And what percentage and distribution of steam vs water vs plasma?

    The steam/plasma expansion may add a sizable amount of force to the explosion of the impact itself. Steam is a huge driver in volcanic eruptions, and that is over time. An instant steam/plasma event has to have magnitudes more expansive energy driving the ejecta.

    More comments later… still reading.

  54. Agreed, we need Saginaw Bay mega science to reveal a smoking gun, or even a lack thereof, conclusively to move forward.

    I’m still grappling with the twin lobes of the Mars Butterfly Crater, with the experts telling me the projectile gets ‘decapitated’ in the impact, which sounds fishy. when a projectile comes apart mechanically because of overload in a hypersonic impacts, it doesn’t break into clean chunks and turn at angles after flying a crater width down range, suddenly aimed back at the surface.

    Both the smaller leading crater and the main butterfly crater of Mars have a secondary lobe down range. I’m calling it the ‘tail pocket’ for now. I think is a shock wave related phenom.

    TH

  55. Michael,
    can you confirm deep excavation of Saginaw Bay? In the GSA video above you seem to state “50,000 Carolina Bays” and “tens of millions of cubic km” of dirt. — Is that really what you said. One million cubic km is a box of dirt 100 km along each edge. If all excavated at once that would be a very large crater. Saginaw Bay is only 50 km across.

    George,
    reading up on Carolina Bay dates again, the YDr contemporaneous hypothesis still seems likely (am reversing self from my earlier comments, only known counter-argument was archeological, Clovis people cultural remains on top of CB rims alleged, but have seen no evidence of this). Michael Davias in above GSA video states the age as “between 10,000 and 15,000 years ago,” i.o.w. he gives 15 K years as upper limit of age possible.

    Tom, Steve,
    can’t figure denial of suborbital incoming, no other process is available to deliver CB-grit material down from Saginaw Bay or points North. Michael Davias pretty much proved the Saginaw Bay impact caused the Bays, to my mind at least. See his web pages and above GSA video.

  56. TH –

    Larger ones would conserve velocity better and require less initial (launch) velocity to reach a give range. Smaller ones would slow down faster and hit more vertically, lower cannon ball factor, and that I believe is critically important. Naturally there would likely be some distribution of initial ‘launch’ velocities of these puppies so more variables to sort, but….

    I think I disagree with the larger = farther idea here. F = ma says larger ones get less initial velocity, no?

    Also, based on Mt St Helens data, sand sized went farthest and larger ones went shorter. That initial impetus was from steam, not impact, but still… If volcanoes are that different, I can understand if there are reasons, I am all ears.

    Schultz’s video results seem to show that most ejecta go vertically, more or less, unless I am misreading the video (which is possible). But with few (maybe no) surface features between the CBs and the Great Lakes, what are we to think? Perhaps Schultz’s work does not apply?

    Yes, initial velocities will vary, but with the vast number of ejecta an average may be determined (either by statistics and/or empiricism or models) and used.

  57. CORRECTIION: Lake Michigan replaces Saginaw Bay, M. Davias in Part II of his Asheville GSA video. He seems to envision a series of impacts to explain the oblong shape.

  58. The nature of the CB sand may help here in terms of isotopic signature and all other possible details for origin ID. Item #4: If a giant shock fractured, steam blasted, trans-atmospheric, transonic chunk of ice, only a hundred meters big or so, hits hard ground, would it splash, or would it crater or maybe even bounce? If it bounces wouldn’t it leave a chain of marks?

    If it is shock-fractured or steam-blasted, the CB impactor would splash, making tertiary impact features, most of which would be not aligned. At the least, these would have blown out many portions of many of the rims of the other CBs. Ergo, this doesn’t seem to be the case.

    If solid enough to bounce without breaking/splashing, they would leave deeper cratering.

  59. Item#2, chunks of LISheet, seems like a great answer because for some unknown reason the Ice Sheet had plenty of sand of essentially equal grain size already in it, and also because the icebergs magically disappeared after landing, leaving no central impact signature upon landing, even though they were solid enough to be launched suborbital w/ 5,000 Gs acceleration (a complete guess so don‘t get excited) from an astronomical impact blast. Oh yes, and they were ½ mile in diameter on average (another complete guess, please stay calm). But no craters. Is anyone feeling the love for that answer, because I’m actually having some trouble here.

    No, not feeling the love on that one:

    “…chunks of LISheet, seems like a great answer because for some unknown reason the Ice Sheet had plenty of sand of essentially equal grain size already in it…”

    I read it that the shredding was essentially by plasma/steam forces as the creator of the uniform sand size. At and above the ET impact site. Think of it: Steam similar to volcanic steam, but all released in less than a second. What kind of shredding? MUCH more than from a volcano, which releases its pressure over hours and days. I think there should be impact shock telltales in the sand.

    Even the 5,000Gs of lofting force itself should add to the shredding. Some may prefer to call it ‘pulverizing.’

    As to the size of the CBs, it would require a size-sorting at the ET impact site, re initial velocities and loft angles. The CBs are the ones of a certain size range and velocity. Higher velocities would, apparently, shred. I think we all can agree that at SOME initial velocity, the ejecta chunks/icebergs would be torn apart. Lower velocities would land short (but if so, where are those impacts, right? – I don’t know.) Perhaps if the initial velocity was high enough the CBs WERE the lowest velocity ejected objects.

  60. [TH] Wait – what about answer #5? Remember the vortices of plasma that we get with ET impacts – and what we get w/ moving plasma is electro-magnetic domination of the dynamic equation. The Sandia factor. That’s right, I’m thinking the sand held hands. What do we know about natural yet freakish cases of plasma torrid behavior?

    This may not be so outlandish an idea. Out of the box, yes, but if ionized, it is not unreasonable to suggest that the quartz in the sand sand particles had static charges. Do I recall correctly the static in volcanic ash clouds? I think so.

    The water vapor particles in any cloud must have similar charges (which on first thought must push them apart), because lightning travels from one cloud to another – requiring one monolithic (and opposing) charge in each of the two clouds involved. What makes each cloud not push itself apart? We all think that afterward both clouds are neautralized, but are they really? I’ve seen MANY a ‘heat lightning’ cloud have lightning bolt after lightning bolt shoot from or to it – from the same other cloud. Does the charge get built up that fast? or are we missing something about clouds and charges?

    Is it possible something similar happens in volcanic clouds or in ejecta-plasma clouds? Do they ‘hold hands’ in some way? If so, it must be a force greater than the electrical repulsion we would expect.

  61. Greetings :

    Allow me to respond to Herman’s questions and observations:

    >>>>>>>>>>
    >>can you confirm deep excavation of Saginaw Bay? In the GSA video above you seem to state “50,000 Carolina Bays” and “tens of millions of cubic km” of dirt.
    >— Is that really what you said. One million cubic km is a box of dirt 100 km along each edge. If all excavated at once that would be a very large crater. Saginaw Bay is only 50 km across.
    >>>>>>>>>>

    The proposed Saginaw Impact Structure has replaced the Lake Michigan suggestion I had made at the AGU in 2009 (the video). The “crater” floor extends well beyond the current water-filled Saginaw Bay. The volume contained is, as you note not im the millions of ckm, but in the tens of thousands. I proposed that 10% of the excavated material would comprise the distal ejecta creating the bays. My rough math suggests that 1,600 cubic km of debris would be capable of blanketing 300,000 square kilometers of North America with a 5-meter thick distal ejecta sheet. An image is available to demonstrate a low-impact angle crater (actually, one from Mars) would look imposed at the site: http://cintos.org/ge/Portraits/Saginaw_Superbowl_web.jpg

    >>>>>>>>>>
    >> Michael Davias in above GSA video states the age as “between 10,000 and 15,000 years ago,” i.o.w. he gives 15 K years as upper limit of age possible.
    >>>>>>>>>>

    Again, the video is 2 1/2 years old (12/2009). I currently put the date at between 120,000 and 150,000 years based on OSL dating. See my blog post on Google+ : https://plus.google.com/u/0/b/116809798718815911632/116809798718815911632/posts/hcqmZcvbdKZ

    – Michael

  62. Steve Garcia
    “lightning travels from one cloud to another – requiring one monolithic (and opposing) charge in each of the two clouds involved. What makes each cloud not push itself apart? We all think that afterward both clouds are neautralized, but are they really?”

    Actually the clouds are typically all the same sense of charge with respect to the ground but at different magnitudes, which is plenty to generate the lightning. The cloud IS pushing itself apart when it ionizes the flow to create the charge. It has been energized by the destabilizing potential of imparted heat from below in a vertical pressure gradient, with buoyancy then being the driving force.

    The shearing vorticity of turbulent flow in those convective cells has a very high ion generating effectiveness, and so different quadrants of the convective cells discharge between each other as the capacitive dielectric of the atmosphere is exceeded by the variable field strength potential (volts/meter) between adjacent cells. Their various plume expansions strip and build up charge, then discharge randomly with the chaotic turbulent development.

    During the unstable process of convection, a cloud becomes a capacitive semi-conductor. Just don’t fly between them when they’re like that. It gets difficult to navigate when the compass spins around every time the lightning strikes. And there can be hail in that environment, which definitely makes flying ill advised. And its really bad for your hearing when it arcs through the airframe. Very bad for landing light bulb filaments as well. That’s what I heard at least.

    TH

  63. Michael, thanks. Shocked to learn (from your web page reference) that Sangamonian (125-75 Ka BP) not contemporaneous fully with Eemian (130-114 Ka BP). Apparently while Europe was glacial post 114 Ka BP, Canada remained ice-free for another 39 Ka. Astonishing!

    There are way too many far Northern bolide impacts for my taste. Rational inference: The ones in lower latitudes have not been found, may have been oceanic. Very similar situation with W USA vs E or central. In the W deserts we have a large number of fairly recent calderas (hotspot, so ET bolide impact caused), at Yellowstone, Valles (Los Alamos NM), Long Valley (Mono County CA). These are all Miocene or Pliocene if memory serves. There should be at least as many further E in the USA. Where are they?