I am trying to get the Powerpoint from Michael Davias, which I will post. I am sure it is very, very cool. His website is here: http://cintos.org/
Goldsboro Ridge: How does a lake form on a hill?
SURFICIAL QUARTZ SAND DEPOSITS ON THE ATLANTIC COASTAL PLAIN: EOLIAN, FLUVIAL OR MARINE? THE CASE FOR A CATASTROPHIC DELIVERY MECHANISM |
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| DAVIAS, Michael, Cintos Research, 1381 Hope Street, Stamford, CT 06907, [email protected] and GILBRIDE, Jeanette L., Cintos Research, Raleigh, NC 27613Regions of the Atlantic Coastal Plain are often capped by a surficial sheet of quartz sand. For example, the Pinehurst Formation sands are mapped as a separate unit, distinct from the well-provenanced terraces below. The Goldsboro Ridge sand is also distinct, resting on the Sunderland formation. From the Carolina Sandhills eastward to the coast at Wilmington, a nearly continuous and occasionally thick (up to 10m) sheet of high purity quartz sand is blanketed across the intervening terraces and scarps. While the Coastal Plain surfaces show evidence of eolian reworking, studies of the deeper extents of these sandy deposits often mention difficulties in determining their geomorphology, although deemed as gradualistic eolian, fluvial or marine. Marine deposition is appropriate at the coastline, supported by glacial-driven sea level transgressions; but they contain no shell fragments. Inland, deposition on interfluvials during flooding of is reasonable; but these are coarsely skewed, showing no sorting or channeling and minimal clays. At higher elevations, workers implicate eolian deposition on undissected terrain; but delivering coarse sand upslope from distant drainage mandates powerful winds. Oriented ovoid Carolina bay depressions have evolved in these sand sheets, seemingly without deforming or altering the antecedent strata and paleosols they rest upon. They are present in prodigious quantities and may represent diagnostic markers for these distinct sand deposits. In an attempt to identify a universal mechanism for the materialization of these sand sheets, we speculate on an aerial deposition, mobilized and delivered as a “rain” of pulverized distal ejecta emanating from a cosmic impact. The bay depressions may be artifacts of steam outgassing, frozen in time as the sand transited from liquefaction to lock-up, preserving an arrival vector in their orientation. Using data from our LiDAR-augmented geospatial survey of 30,000 Carolina bays, we note systematically varying orientations and robust adherence to archetype planforms. A triangulation network, built using bay orientations and considering the Coriolis steering of trajectories, suggests a probable source impact site. While such a catastrophic mechanism is unorthodox, our survey data and analysis suggests further research is warranted. | ||
| Southeastern Section – 61st Annual Meeting (1–2 April 2012) General Information for this Meeting |
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I highly recommend this closely related presentation from Davias to 2011 GSA in NE Section in Hartford, Conn. The ending extraordinarily interesting so I recommend reading it back to front.
As always the papers submitted from Davias and Perigee Zero begin with such playful innocence, then make the claim of an impact event so enormously large and and complicated that I cannot help but smile. Well done again. I note that the theory has evolved or morphed in regards to the time sequence. Previously an impact date of 30k years in the past has been postulated, I see now that a likely date of 17k years in the past up to the YD Boundary date are postulated. Have there been any C14 studies of materials at boundaries or some of the buried cypress forest sites that are yielding these new ranges? Thanks for the post on The Tusk
Re cell 94:
There were scores of hypotheses by the 1950s, as I recall. The aeolian one was onf of those whcih came up short then, yet somehow the post-1990 folks have latched onto it despite its long history of failing to account for the facts – and to present it as if it was a simple and clear explanation that left no stone unturned and left no doubt as to its corerectness. Time after time, they present it as the one and only cause. It is as if they believe that if it is repeated enough times (ala Goebbels and propaganda) it will somehow be accepted as true, and that accepting it as true will magically make it true. I get really pissed when they do that.
Note to aeolian believers: IT DOESN’T WORK.
Re cell 95:
Is there any chance you could break this out for us in one-syllable words? I almost get it, but not quite. I think I was close last time, but not quite.
Re cell 96:
Surely with so many polling companies using 900 or 1,000 as sample populations in elections were millions vote, the statistics is solid enough that a sampling of 250 bays should be able to get within a degree or two for all the 30,000 sites. Or have these people never heard of polling or random sampling? Given the consistency shown on cell 89, there can’t be moer than a degree or two difference, even if you used the least favorable sites.
Re cell 96:
Given the slight slope up to the right on the distance graph, a couple of questions/comments arise:
QC1: Is there a location which does not give that slope but a flatter one?
QC2: Intuitively, with the alignment of Saginaw at 221° and the suggestion of an incoming impactor from the NE, it seems to make sense that the ones further up-field would carry a bit more inertia. Is this how you read it?
QC3: Until I saw the idea sheet superimposed, I did not understand the minimal area of bays in NE and KS.
QC4: Why would there be none inn the up-field zone between KS and AL? Any cosmic understanding on that, as a feature of impact?
QC5: And given the dating that so many (including Ed Grondine here) have thrown out about the CBs, mostly all much before the HCI, how do you deal with that?
QC6: MANY have given up on the HCI as being connected to the CBs. Could this be a separate and earlier event?
Here’s an interesting experiment someone else might want to try under controlled conditions.
On a large flat surface, such a big concrete pad spread a thin (1/4″ to 1/2″)layer of fine sand. (about 20′ X 20′)
Next, take a small explosive device and set it into a small pan of water, and cruched ice, that’s setting in the middle of the sand. A 12″ deep-dish pie pan will do nicely.
(For the explosive device, I used an M80 that I attached an electric fuse to like the ones they use in model rocketry, and then water proofed with clear silicone)
It remains to be determined whether or not the results are scalable to something the size of the CBs. But when you set off the explosive charge, the ejecta pattern the slushey mixture of water, and ice, makes in the thin layer of sand surrounding the explosion will be a perfect scale model, and fractal representation, of the CBs
One more thing:
From Evidence for an extraterestrial impact 12,900 years ago that led to the megafaunal extinctions and the Younger Dryas cooling. by R.B. Firestone et al, 2007 we read:
That “unpublished data” by Pete Schultz is easy enough to find online. And Dr. Schultz’s work at the HVGR is extremely important because it represents the only valid experimental data we have that can give us a clue of what actually happens in an ice sheet impact, and the nature of any remaining resulting sub-ice scarring. Especially if we don’t want to base our thinking on mere assumptions, and suppositions.
Pete Shultz’s Hypervelocity oblique impact experiment into a surface protected by an ice sheet can be seen in this video on YouTube. The segment that has Pete’s experiment at the HVGR begins at about 03:00 into the video.
It’s been five years since the paragraph above mentioning that data was written in Firestone 2007. Yet people are still obsessed with finding a “crater” somewhere on the Canadian Shield. And in also spite of the fact that the only real experimental data we have indicates that whatever the actual planetary scarring of Ice sheet impacts that may have produced the CBs is, there is a very real probability that that scarring bares no resemblance whatsoever to what we’ve assumed an impact structure should look like.
My point here is that there is a very real probability that we won’t find any shock metamorphic effects at all anywhere in the Canadian Shield. And that any remaining scars may consist of something we never imagined might be related to an impact event.
) M.D. Higgins et al., “Bathymetric and Petrological Evidence for a Young (Pleistocene) 4 km diameter Impact Crater in the Gulf of St. Lawrence, Canada,” (2011): Presented at the 42nd Lunar and Planetary Science Conference, Houston, Texas. It would be interesting to follow up on Dr. Michael Higgins work to determine if in fact the 4 km. wide crater can be dated. More excting still, if it was dated around 13,000 BP. I tried to find any follow up material to the above, but so far have had no success.
Davias is slowly but surely ripping the sheets off the bays, I wish could be up at Asheville GSA today and tomorrow.
Among the many problems with the ideas presented by Davias the most problematic relates to the fact that the Carolina bay are clearly and empirically demonstrated to be long-term evolving geomorphic features of the Coastal Plain rather than synchronous events. You have to separate ideas about original depression formation from hypothesis about Carolina bays since the orientation, shape, and multiple bay sand rim formation (common to many bays) are all features that have evolved over many millennia. This is most clearly demonstrated by the fact that many bays have multiple sand rims that have formed in a regressive sequence including limited bay migration due to subaqueous scour during open water phases. The bays are analogous to migrating meandering rivers but over much greater lengths of time. OSL dates confirm that bays with multiple rims have progressively younger sedimentary deposits as you move basinward. Whatever the cause of the original depressions it has very little to do with what we see today. Orientation and bay “planforms” change from region to region and are correlated with prevailing wind patterns.
As far as the YD hypothesis is concerned, the data are looking better all the time in its favor, but Carolina bays have nothing to do with a YD impact since they are demonstrated by OSL dating and archaeology to be far older that the YD event. Carolina bays are neither enigmatic nor mysterious…they have been relatively well understood for some time as resulting from high-energy lacustrine processes from wind on shallow ponded water. There are many details of oriented lake formation (particularly for Carolina bays) that still need to be worked out, but the general framework is understood and doesn’t require resorting to catastrophic explanations.
“This is most clearly demonstrated by the fact that many bays have multiple sand rims that have formed in a regressive sequence including limited bay migration due to subaqueous scour during open water phases.”
Chris, I would guess bays with visible and multiple regressive rims would be less than 1%. So right off the bat you are directing us to the exception and not the rule. Just look at Davias’ older presentation from the Delmarva. How many of those features show “multiple rims”? Or perhaps those are not “bays”? I support his contention they are. And the vast, vast majority of more southern bays also show no evidence whatsoever of “multiple” rims.
Thanks for commenting, though. That’s all I have for now.
Chris –
The aeolian and lacustrine cause of the CBs was rejected long, long ago (the 1950s), yet the aeolian people keep coming out and claiming it is THE approved explanation, when it is not.
When wind and water don’t cause such things anywhere else, this explanation is just a wishful thinking speculation, with confirmation bias all over it. That alone certainly doesn’t make it a YD impact event, but it doesn’t even hold water in its own right. And if you think it does, look at Davias’ LIDAR, then actually LOOK at it once, instead of just spotting the headline and jumping in here again without looking at Davias’ data – and saying the same old, “We’ve explained it, people,” mantra, because you haven’t. Then explain to us why the papers since back the 1950s rejecting aeolian/lacustrine were wrong, and INCLUDE Davias’ work to show us where his data don’t ALSO blow your assertions out of the water. Appeals to authority don’t work here. Give us facts and back them up.
Steve, Thanks for your comments, but lacustrine include both higher energy shoreface processes involving wind on water AND eolian processes. You should really check out more recent literature than stuff from the 1950s. Oriented lakes are found all over the world. Send me an email if you want me to send you more recent literature. Bay sand rims (multiple or single) are demonstrability shoreline features. If you actually look in detail at the sediments (we have) then you see clear evidence for lacustrine depositional environments (not catastrophic emplacement). OSL dates demonstrate that bays are long-term evolving features. The example I used before with bays with multiple sand rims shows this most clearly. George is right in that most bays don’t have multiple rims, but it’s the exceptions that prove the rule. By the way, I use LiDAR data extensively myself, but I also do fieldwork and collect data.
It is amazing to me the ones that want to rule out an impact. It is my hypothesis that The Carolina Bays ARE in fact craters, but not old, in fact quite young. I believe they were formed from meteors coming from the dust tail of Comet C/1811 F1 [two-hundred years ago]. These meteors were comprised of only ice, sand, and dirt. This is the reason for such a lack of evidence.
It’s my opinion that because of where this land is located and it’s make-up [soil horizons], there would have been a great amount of erosion, probably farmed and developed extensively in such a long time frame. These impression are still way too well defined. As all are aware they are elliptical, all run in the same direction, and have sand around the rims. They did have to stop the farmers from plowing through them, right?
I believe that the soil and sand content that was tested was from the comet.
Chris, Since some of us have access to many, if not most, of the major scientific journals and actually read the work that gets cited here in these discussions on the Tusk, why not simply cite the "more recent literature" you speak of by Title, and Author, instead of cryptic and veiled references to literature you’re only making available by special request email?
Also, a direct quote of the relevant paragraph in the literature you cite, and accompanied by a brief explanation of how it applies to the point at hand would be extremely helpful.
Hi Chris,
I’ve been looking over a couple of your posters at http://www.sarp.org, namely: ‘Geoarcheological Investigations of Carolina Bays in South Carolina: Methodological Approaches for Interpreting Site Formation Processes, Archeostratigraphy and Geochronology, and Evidence for Widespread Eolian Activity in the Coastal Plain Uplands of North and South Carolina Revealed by High-Resolution LiDar Data I have to confess, they are pretty darned interesting.
And while I no longer think the CBs were formed by the YD trigger event, (they are clearly too old) I remain to be convinced that Eolian, or Lacustrine processes can adequately account for them either. But that’s not my point.
I note that your hi resolution stratigraphic work comfortably straddles the P/H transition, and the Younger Dryas start. Yet in spite of all the controversy about the trigger event for the YD I don’t see any specific attention given to identifying the YD boundary horizon, or the potential to confirm or deny possible ET markers there.
Why not?
Hi Dennis… I’m actually quite interested in determining if depositional processes were more active during the Younger Dryas and other rapid climate shifts. The OSL dates that bracket the YD from our bay research are in the upper meter of the sand rim. That is where the archaeology is (Clovis to Mississippian) and where most of our research focus is. The sand rims in our area are usually no more than 3 meters thick, so the rims are actually much older than the YD. As depositional basins, Carolina bays are likely to contain YD impact markers (assuming the impart occurred) since bay basins will store material input from the atmosphere and deposit that material on the sand rim. I happen to think recent data are consistent with some type of impact or airburst during or just before the YD…its’s just that bays have nothing to do with it. Basal rim OSL dates for several bays in South Carolina date to more than 100 ka. Others are younger.
Chris –
None of the oriented lakes has anything except that in common with the CBs. And you would know that if you looked into it. None of them are sandy or shallow. The Beufort Sea and Mena River ones are completely different. The Rio Cuarto ones are accepted as impacts by the crater database folks. Now tell me how those have anything to do with the CBs.
Lacustrine features are never full ellipses. They are windblown into curves only downwind, never upwind. Vortexes forming ellipses – please show us an example somewhere. And vortexes cannot possibly overlap like the CBs without a mish-mash of the joining. The CBs don’t do that.
The dating is the only issue the CBs have related to the YD. But that does not make them lacustrine or aeolian, either.
You talked about an example with multiple rims. There is nothing in the impact scenario that prevents wind or water from having a secondary effect. I cannot see how this is relevant.
Your homily that “it is the exception that makes the rule” means nothing, and sounds like a way of denying the bulk of the evidence and give all weight to the very minor cases. Exceptions only make the rule when the exceptions AND the vast majority all fit into one. Your interpretation doesn’t fit all, so you tell George his are outweighed by yours. The tens of thousands don’t count?
Kalopin –
It is not enough to ‘believe’ one way or another. We are trying to inform ourselves of solid evidence and use that to arrive at some explanation. Believing has to be left at the door. Believing has to do with leaving out our critical faculties. Why would we do that?
If you want to think it was a direct comet/meteor dust shower you would have to explain why the ones out in NE/KS exist also and also point to the same Saginaw/NI area. And you would have a big problem with there not ever having been found ONE meteor in any CBs.
Your ideas have long since been found wanting, but that doesn’t mean that in some way everyone else overlooked something. But don’t feel bad – no one else’s ideas are fully functional, either!
Actually, you can believe whatever you want to believe. Science is very flexible in that regard. The hallmark of a rational mind is the willingness to change your beliefs when new evidence emerges. I had no a priori beliefs when I went looking for an impact crater in Ontario, but I did take the Carolina Bays orientation at face value. I no long believe they are impact features.
If you can present something definitive suggesting that they are, I might change my beliefs.
Dennis –
Good points to Chris about lacustrine, aeolian and impacts. But, you see, that puts us back where things were 60 years ago (actually more). As Davias’ opening quote says it: NO explanation works on all the evidence.
Chris –
As to the 100kya dates for the CBs – that may well be true. It is why many have abandoned connecting the YD and the CBs. I have a problem with it, too. Yet to say that impacts had nothing to do with the CBs – just because they weren’t the proper YDB age – does not rule out earlier impacts. The two issues are separate. The CBs could be caused by impact at some other time than the YDB. Ed Grondine would have a cow over us even talking about it; he considers the two mutually exclusive.
But I want to point to a book (Kindle available) “The First American: The Suppressed Story of the People Who Discovered the New World”, about an archeological site in the 1960s (Valsequillo, outside Puebla, Mexico) that had VERY inconvenient geological dates of 240kya in some spots and much more palpable 22kya in others – these are dates tied to human artifacts. The site was abandoned because the dates were impossible. At the time, modern humans even in Europe, were only thought to go back 40kya. Over the next 50 years modern humans were found to go back to at least 380kya, which would have made the geological dates at Valsequillo palatable, if not still problematic. Even humans crossing deep ocean was pushed back to long, long before Clovis. The point here is the differences at Valsequillo of 22kya and 240kya. Two datings were tied together with artifacts at the same site and were so close together physically, yet were so far apart in time. Even at the time, they were well aware that even the 22kya dates blew Clovis out of the water, but they could stomach that – but not ten times older. It was the gelogists who were eventually vindicated by findings elsewhere, from Flores, from Siberia, from Georgia in the Caucasus, from Germany (380kya honest-to-god javelins, for Pete’s sake) – though even that has been spun into homo erectus, not h. sapiens.
Back to the CBs I would want to rule out that the 100kya rim dates could not have been exposed sand at 100kya later thrown out in the rims. I know, it sounds like grasping at straws in a way, trying to squeeze the CBs into the YDB. But solidifying what it is NOT is part of narrowing out what it COULD be.
The YDB black mat has only the Alvarez 65Mya layer as the only similar layer in the sediments (as far as anyone can see). Thus, an impact event at 100kya would have to have been big enough to splatter ejecta between NE/KS on one side and the Atlantic seaboard on the other – yet still not big enough to cause a black mat.
Even if an impact ever gets ruled out by objective researchers, the lacustrine/aeolian fails on its own d(e)merits.
Whether or not CB=YDB, impacts still seem to be a better explanation for the CBs than anything else. Davias’ data makes that even more likely. When? We don’t know yet.
Oriented lakes have to do with Carolina bay, because Carolina bays are a type of oriented lake. The fact that other oriented lakes form in different sediments is irrelevant. Uniformitarian processes create these all of these features.
You need evidence that circulation cells within shallow ponded water can form an ellipse? Have you read Kaczorowski’s (1977) dissertation. He created elliptical and oriented “Carolina bays” on a wind table and measured circulation cells within various oriented lakes including Carolina bays that were consistent with his wind table results. These circulation cells scour and shape bays perpendicular to prevailing wind patterns and move sediment to shorelines where they are worked into rims through high energy waves and wind.
I think you may be confusing original depression formation with bay formation. You need natural depressions to form bays, but Carolina bays are evolving features and effectively change or completely erase whatever form the original depression was. In the process they shape, orient, and create single or multiple bay sand rims. Any natural depression in the right setting could conceivably (given enough time and the right environmental conditions) form a Carolina bay. Could some of the original depressions have been craters…possibly, but the shape and orientation, and the bay sand rims we see today have little to do with the original depression and instead reflect long-term pervasive influences of climate and prevailing wind on shallow Quaternary cover sands overlying older (usually marine or estuarine clayey sediments) that pond water. Empirically this has been demonstrated because we and others have done analyses of sediments, coring, geophysics, and chronometric dating. Much of this work is ongoing by various groups of researchers in the Southeast. Do we understand all of the nuances of bay basin and rim formation? Of course not, but if you (or others) are going to put forth an “unconventional” catastrophic mechanism for forming bays when geological evidence flies in the face of that hypothesis, then it is you that have the burden of proof.
In this case, the “exceptions” are showing us in a very clear way the fundamental processes that create these features. What “bulk of evidence” are you referring too? Why does my interpretation not fit all? The fact that most bays don’t have obvious multiple sand rims is irrelevant. I’m sorry; I don’t follow your logic.
Our “burden of proof” you speak of may not be as far out of reach as you might think Chris.
Since the stated astronomical model for the hypothetical YD impact event is now officially Clube & Napier’s work on the Taurid Complex, then perhaps it wouldn’t hurt to pause at this point and consider what that means for the proposal that the CBs might be related to a major impact into the Laurentide Ice Sheet. As well as what the resulting planetary scarring might consist of, what it might look like today, and the potential age of that proposed impact.
First of all, since the Taurid Progenitor object is thought to have entered the inner solar system, and a short period orbit of only about 3.3 years, somewhere between 20,000 and 30,000 YA. And it is also thought to have started breaking up immediately, this world would have faced a far more concentrated and dangerous debris stream from those progressive breakups than the harmless, and pretty, light shows we see from the Taurids today. So that the devastating impact storms of the Taurids could’ve been happening twice a year for thousands of years, both before, and after the YD trigger event. And the YD event was probably just the worst of many.
If we are going to use the Taurids as our astronomical model, then the whole “Coherent Catastrophism” paradigm Clube & Napier have been talking about for 30 years now becomes a fundamental part of the postulate. In other words, if we’re going to use the Taurid complex as our model, then I think it’s time to recognize that finding dates for mass extinctions, and planetary scarring that are all over the place is perfectly consistent with the progressive breakup, over a period spanning 10,000 years or more, of a giant comet in a short period, Earth-crossing orbit.
And instead of single bolide events it’s time to start thinking in terms of large clusters of smaller fragments. And instead of solid objects that deliver their energy by direct kinetic impacts with the ground, we need to begin thinking about airbursts; big ones with fireballs and impact plumes capable of efficient melting, and ablation of the surface.
So we have a paradox to unravel. Lake Cuitzeo produced materials that could only have formed under such conditions. But according to the old Uniformitarian/Gradualist paradigm, only terrestrial volcanism is thought to be capable of producing enough heat melt the surface of the Earth. This means that there is a very real probability that pristine melt formations exist that are in fact, some of the planetary scarring of the YD impacts. But they have been misunderstood by geologists of the past who couldn’t imagine such violence coming from the sky. So those materials will be misdefined on the geologic maps as volcanogenic when they’re found.
As for the ice sheet impacts, if we step outside the box, and toss our assumptions that they must have produced a crater somewhere, we can come at the problem from a forensic perspective and predict what any remaining planetary scarring up north might actually consist of.
If any of the heat of those ice sheet impacts reached the surface below with sufficient energy for melting to occur, then that melting would’ve happened suddenly under conditions of great pressure, and in the presence of a lot of water. So instead of shock-metamorphic effects from the direct kinetic impact with the ground, any remaining planetary scarring in the Canadian Shield should consist of hydro-thermal metamorphic effects. And that scarring won’t bare any resemblance whatsoever to anything we’ve ever associated with an impact event.
But remember, any melting event will reset the K/Ar clock to zero.
Again, the melt formations can be expected to be found on existing maps as “Volcanogenic” or “Volcaniclastic”. But since the most recent volcanic activity in the Canadian Shield are some dyke swarms that date to about 1 million years ago, and except for that, the Canadian Shield has been volcanically stable for more than 2.5 billion years, our proof, and smoking gun, will be a piece of rock from one of those surface melt formations that returns an age-since-melt of only thousands of years.
Hi Chris –
Do you have any data on a uniform marine sediment strata dating roughly 1,000 BCE in the fill of the bays nearer the Atlantic coast? Like the strata found at the Baucom site?
Dennis –
Yes, Clube and Napier’s work is the anchor.
As much as I’d like to think the Earth was bombarded by big fragments of the Taurid progenitor, especially early after fragmenting, from what I’ve seen there are only two layers that show something devastating happening on Earth. One was the 65mya Alvarez meteor and the other is the YDB. Nothing else is in the sediments. If I am wrong about that, let me know. But if not, then the the YDB is the only game changer from the Taurid progenitor.
Tunguskas and larger? Probably – based on Ed’s list and other anecdotal and historical info. SOME of those are likely. No black mat ones, but big enough.
Thanks Steve,
But in fact,there is no reason to assume that all large multiple fragment airburst storms had to produce an ‘impact layer’. It’s entirely possible that we only see evidence of impact induced fires and dust in the stratigraphic record if there was a land impact. Remember, most of this world is covered by oceans.
An ocean impact of such an event might produce something completely different.
In addition to evidence of mega tsunamis, does anyone have a handle yet on what the climate consequences of instantly evaporating a few tens of thousands of cubic miles of sea water, and cometary ices, directly into the atmosphere would be? Or what the chemistry in the resulting stratigraphic horizon might look like if there was no melting of terrestrial rocks, or burning of biomass in the event?
Dennis –
Yeah, I am in agreement that not all large single or multiple fragment airbursts (or ice sheet air bursts or impacts) would produce ‘impact layers’. Land impacts – that would contradict what everyone is thinking about the YD onset event being an ice sheet impact or air burst. Then we WOULD want to find a crater, or a focused point of impact markers. The Tunguska air burst did not cause any fires at all, not that I have heard about. If a larger comet air burst would, some think so. I am not up on that aspect of it, but others (I think maybe including you) talk about radiant heat from plasmas. Meteor people argue that meteors do not come down hot, that quickly recovered small ones are actually cold, except for the outer few millimeters.
So how does the fire start when there is one? Especially a continental one. And how does that translate into a black mat in both Mexico and Belgium/Netherlands and across most of the USA?
And I agree that the vaporized/superheated water – from an ocean event or an ice sheet event – expanding directly into the atmosphere needs to be looked at. Actually Michael and I were talking about that in comments on his LIDAR post before, about it going up above the atmosphere. We aren’t talking about something that looks like Mt Pinatubo; we are talking much bigger – and the explosiveness is GFAR above a volcano that feeds its magma up to the vent relatively slowly. This is ALL of it being heated in a heartbeat – maybe half or one km across before heating and before the shock wave pushes the water outward. With a water cavity maybe several kms across, there is at lest that much water being heated well beyond steam.
Explosions only have mushroom clouds when the downward blast is reflected back up and adding to the upward blast. But look at the ice blast in the hyper-velocity tests. The ice went up much higher than sand when no ice was on top (and almost straight up, too) – and that was only at 1/5th the velocity of an incoming comet or meteor. The some of the ice or water would, (I think) stay as ice or water, but most would be heated as you say much beyond steam. And as steam it would be rapidly expanding.
So it may be high velocity ejecta as plasma, as ionized vapor, as steam, and as water or ice.
This is, I know, all images conjuring up stuff and is a worthless as Plato and Aristotle talking about the four elements.
Steve,
A note on a “focused point of impact markers”.
In point of fact, at something like 10 centimeters, the impact layer at Lake Cuitzeo is dramatically thicker than anyplace they’ve tested so far. So they’re getting closer to the source of much of the violence. This is consistent with something I’ve been saying and writing about for three years now; that there was more than one major impact zone for the YD event.
In the geophysical world according to me there were two large clusters of fragments that hit North America, not just one. The impacts into the Laurentide Ice Sheet were from the smaller of them. And the impact zone of the larger cluster hit North Central Mexico, and much of the Southwest. I also think that California took a major hit.
And I think that once all the data is in, it will be realized that the YD event was a couple of orders of magnitude more violent than anything anyone has ever imagined. It will also be realized that the old 19th century process of mutual inter-assumptive-confabulation that is the Uniformitarian/Gradualist paradigm is perfectly useless for understanding the planetary scarring of the event.
Be that as it may, I think there is a hell of a lot more evidence to dig up in Mexico. And at Lake Cuitzeo they’ve barely scratched the surface.
Yeah, four inches is a lot of black mat.
And most people seem to talk about multiple objects. I can’t argue against it. And after 1994, who can deny it happens?
It is pretty clear that some of what is down in NW MX and SW USA is impacts. But I do agree with Ed that impacts didn’t just happen at the YDB, and that those MX-USA sites need to be dated. That may not be what you want to hear, but for now they are only possibles for that period. The pattern of them (SE-NW) seems to be inconsistent with the direction of the Saginaw hit (NE-SW).
But the thickness at Lake Cuitzeo does imply closer to ground zero (at least one of them). Implying isn’t enough, though. Let’s keep it in mind.
Funny you should mention the ‘old 19th century process of mutual…” I just found an 1885 book, apparently a textbook, and that is exactly what they were doing. They read every feature as uniformitarian and ice age, and patted themselves on the back for doing so.
Uniformitarianism died in July 1994, even if they don’t know it yet.
Chris –
Taking your dune_2011.pdf alone for the moment, after looking through that whole thing I see one external un-sourced reference to CBs being ~100ky old. The rest of it makes no comment whatsoever to CB formation. The only mention of CBs is that eolian action reworked some CBs.
The ‘eyeball plain English” of the pdf is that it is quite clear from the eloian LIDAR evidence how eolian action looks long and narrow or parabolic, and the long and narrow action is chaotic. The parabolic ones never ‘complete the ellipse’, remaining only one half of an ellipse.
As I looked at panel after panel, I could not help thinking, “Why would Chris say that any of this supports the eolian proposition when it is clear it does exactly the opposite?
There is not one whit of LIDAR evidence produced in that pdf that supports an eolian genesis for CBs. Not that I see.
Chris –
Attention now on the bay_2010.pdf…
Working my way through it, I object to the use of that particular rim on Frierson Bay, since it is a distorted rim and a non-elliptical bay due to the smaller contiguous bay. I don’t object to studying such rims, but not when trying to get a basic understanding of rims. It is not comparing apples and apples, but more like apples versus apples which have already fallen off a tree. The yellow lines illustrate a wild card having been brought into the equation. With 27,000 bays available and 60% of that bay rim uncompromised, it seems totally inappropriate to include that one portion of bay rim in this particular study. I repeat: Yes, I agree that studying those kinds of rims is useful – but it should be done in a comparison AFTER having established a baseline using uncompromised edges.
I also object to the use of labels saying “lacustrine and rim deposits”, “lacustrine shoreface deposits”, and “buried lacustrine deposits”. That is what is being attempted to determine. To call them that before the end of the study is using a thing to prove itself. It is making the conclusive assumption before the evidence has been presented.
In addition, it is NOT altogether certain that all bays have ever had water collecting in them at all, much less. To that end, it is altogether not cool that the locations of the transects in both Flamingo Bay and Johns Bay happen to be right where the water is. I have to say, “Shame on you!” Your transects should have been at some rim length where no water is standing – preferably where no water has ever been known to be standing. Putting the transects where you did is cheating. Putting them where water is NOW and then saying, “See? See the lacustrine effects?” That is disingenuous, Chris. You are stacking the deck.
That makes three out of three rims on bays that appear to be cherry picked.
In the cross section of Johns Bay, the sand dune and sand pit show no more evidence than what the dune_2011.pdf showed: a later eolian reworking of the bay rim. I don’t argue that dunes often are parabolic. That is neither here nor there on CB genesis.
***
Evidence panels:
Lithics: They don’t show much one way or the other. About 1,200-1,500 years after the onset of the YD, human artifacts start showing up – which is what Firestone asserted long ago, and which I believe is standard history. Nothing that shows humans were there before the YD onset.
Grain sizes: Seems to be a discontinuity at the YDB for Flamingo Bay only. No idea if this is significant.
Skewness: Seems to be a discontinuity at the YDB, also for Flamingo Bay only. No idea if this is significant.
The other ones, I don’t know what they are, but they don’t seem to show much, except CV for Flamingo Bay only, whatever CV is.
***
200 MHz GPR transect of Frierson Bay:
Like I said, putting this bay within this study makes a consistent reading of evidence much more problematic, a level of confusion that was unnecessary. This transect illustrates that, IMHO. It shows the disturbance between the two bays (mostly on the right half). Labeling those “lacustrine” is wishful thinking and totally inappropriate. It is stating the conclusion while the evidence is still being presented. But the discontinuity is consistent with some sort of impact, as I see it.
And speaking that, let’s go back to the GPR fence diagrams. I am at least a little bit familiar with lacustrine shorelines. There is one a couple hundred feet above Lake Titicaca – one that is tilted. The strand line on the mountainsides is higher at one end the lake than the other. But the thing about strand lines is that they only appear within a short vertical distance from the top of the water level. These transects show that the deposits are relatively equal, even at the bottom of the bay. That cannot happen if it is shoreline deposits. The deposits would be only on the slope, not on the bottom. This, then, argues that the ‘deposits’ are not deposits at all. The deposits conform to the curvature of the clay underneath. This argues that the clay itself is hollowed out or pressed down. There is no one arguing that the clay under the bays was scoured out by eolian or lacustrine forces. The lacustrine arguments only apply to what lies OVER the clay. That is consistent with later reworking, not something to do with the formation of the bays themselves. That dip in the clay might be considered consistent with a non-explosive (i.e., low-velocity impact such as a secondary impact of ejecta might impart).
The realtively equal layer of deposits over the clay ‘impressions’ is consistent with silting up/filling by sand that blows in, no matter whether there is water in the bay or not.
Again, Chris, nothing in THIS pdf presents any evidence saying that the CBs were lacustrine. Labels do not constitute evidence.
The ‘single-grain’ 100kya dating comes from somewhere else, because nothing in this pdf presents anything older than 13,450 BP. The OSL indicators have no explanation as to what they mean. Perhaps they were done as temporal markers for reference purposes.
Chris, where is the evidence of the 100kya coming from?
So, neither this pdf nor the other seems to in any way show evidence that is inconsistent with impacts, though it is certain that they could not have been hyper-velocity impacts.
From the evidence shown, what I see are shallow clay impressions that were reworked by eolian and lacustrine forces. What made the clay impressions certainly was not lacustrine nor eolian.
For better or worse, I would posit that the best place to date the CBs is not at the rim, but just above the clay bay bottom.
A few articles that might be of interest…100 ka+ basal bay rim OSL dates reported in Brooks et al. 2010, Brooks et al. 2001, and Ivester et al. 2009… All of the recent bay research in the poster (and much more not on the poster) will be published later this year.
Brooks, M.J., B.E. Taylor, and A.H. Ivester (2010) Carolina bays: time capsules of culture and climate change. Southeastern Archaeology, Vol. 29(1): 146-163.
Gaiser, E.E., B.E. Taylor, and M.J. Brooks (2001) Establishment of wetlands on the southeastern Atlantic Coastal Plain: paleolimnological evidence of a mid-Holocene hydrologic threshold from a South Carolina pond. Journal of Paleolimnology, Vol. 26: 373-391.
Ivester, A.H., E. C. Poplin, M.J. Brooks, and G.A. Brook (2009) Life of the edge: the formation of Mathis Lake and its human occupation. South Carolina Antiquities, Vol. 41:1-16.
Fetch-limited self-organization of elongate water bodies
Andrew D. Ashton1, A. Brad Murray2, Ryan Littlewood2, David A. Lewis2, Pauline Hong2
Geology, February 2009; v. 37; no. 2; p. 187–190;
Fetch-limited self-organization of elongate water bodies
Andrew D. Ashton1, A. Brad Murray2, Ryan Littlewood2, David A. Lewis2, Pauline Hong2
PERMAFROST AND PERIGLACIAL PROCESSES
Permafrost Periglac. Process. 13: 61–70 (2002)
Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/ppp.407
Brooks, M. J., B. E. Taylor, P. A. Stone, and L. R. Gardner, 2001, Pleistocene encroachment of the Wateree River sand sheet into Big Bay on the Middle Coastal Plain of South Carolina. Southeastern Geology. v. 40, pp. 241–257.
Hi Chris –
At 100 KYA, the Teas River would have been flowing.
My current estimate is that the Perigee Zero folks may have identified the initial formative mechanism for the CBs’ but that will depend on findings from Saginaw.
The argument for the theory that the CBs were produced by impactites of ice from impacts into the LIS will begin to take on some weight when exogenic planetary scarring in the Canadian Shield can be confirmed that can account for the explosive forces required to loft ice-berg sized chunks of ice a few hundred miles. The Saginaw structure is but one candidate location that cries out for more field work. There are others. And there is no reason to assume that the planetary scarring we are looking for must consist of shock-metamorphic effects such as we see in a Ballistic-kinetic impact crater. Or anything we have ever imagined might be related to an impact event for that matter.
For a few more clues, there’s more of Pete Schultz’s HVGR work at the NASA Ames Research Center in a NOVA episode called The Last Extinction. The link given will take you to the full episode. The part that’s pertinent to this discussion begins at 36:00 into the video. And in addition to an interesting multiple fragment shot, there is yet another example of an ice sheet impact shown there. It’s the condition, and position, of the remaining chunks of ice after the shot that I’d like to draw folk’s attention to.
Some of the candidate locations that have never been considered before as potentially exogenic are some interesting geomorphology that’s commonly referred to as “The Patterned Peat Lands of Minnesota”. And although the standard uniformitarian assumption is that the patterns are related to glacial activity, or might have something to do with Glacial Lake Agassiz, the cause of the patterning remains a bit of an enigma.
We find Our first hint that something isn’t quite right when we look to the USGS geologic maps of the region to get an idea of the rock types found in those ‘Patterns’.
This is interesting because Migmatite is a rock of both metamorphic, and igneous, origin that exhibits characteristics of both rock types. Migmatites form under extreme temperature conditions during metamorphism through the heating (but not quite melting) of rocks in the presence of a lot of water. And where partial melting occurs in pre-existing rocks. They aren’t crystallized from a totally molten material, and are not generally the result of solid-state reactions. Migmatites are composed of a new material crystallized from incipient melting, and an old material that resisted melting.
This is exactly the kind of rock we would expect to find in the burn scars of comet induced, hydrothermal explosions in the ice sheet.
And the meta sedimentary rocks are further described as:
But the problem with the words “volcanogenic”, and “volcaniclastic”, is that there is no volcano there. We are looking at an area of the Canadian shield. The bedrock is Archaean. There hasn’t been any volcanic activity in the area in 2.5 billion years. And, without a volcanic system, you can’t make a case for volcanism as the heat source for the pyroclasts, and metamorphic facies.
So the full range of temperatures, and conditions we should expect of an impact in the ice sheet, from hydrothermal to pyroclastic, is represented by the rock of the ‘patterns’ in the area.
The “Patterns” can be identified in great numbers all the way to the Arctic.
And while the standard assumption is that the patterns are related to glacial activity, the simple unassailable fact is that the movement of glaciers cannot account for melted rock formations, or pyroclastic flows. They can only erode away some of the surface detail. And in hi resolution satellite images of the region, as well as LiDar images, we see that there is no glacial scarring in those pyroclastic flows of “volcaniclastic” and “volcanogenic” rock whatsoever. In fact, they are almost perfectly pristine.
When the peat depressions that form the patterns among those pristine pyroclastic flows are seen as the footprints of icebergs that were the comet blasted remains of a shattered Laurentide Ice Sheet, and that the pyroclastic flows were flowing around and through, it becomes obvious that we are looking at the hydrothermal blast-burns of a very large, multiple fragment event that can account for the almost complete destruction of the eastern end of the LIS in a matter of seconds.
The proof will be in the radiometric data, and an age-since-melt for the “volcanogenic” and “volcaniclastic” rock that’s measured in thousands of years instead of millions.
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
Hi Michael,
Just to make a few corrections to your above statement…First, bay rim sediments are not actually homogeneous if you look in detail (as we have). Sediment generally coarsen with depth and reveal lenses of intercalated sands and gravels at depth. Near surface sediments are finer and are consistent with more eolian contributions (all consistent with high energy shoreface lacustrine deposits). Second, while most near surface rim sediments lack structure, we have deeper rim deposits with dipping clinoforms where the rim has migrated over and buried part of a smaller adjacent bay. Shallow eolian sand sheets on the Tar River also lack internal structure. Third, fossils are occasionally found if you look very closely at very small gravels/pebbles within bay rims. Some of these may actually be reworked fossils from underlying Tertiary deposits. Marine shells simply will not preserve in highly acidic and reworked rim sands given the known age of the deposits. Fourth, with respect to OSL dating, bay sand rims are where most of the recent OSL samples have been taken. We and others have OSL dates from bay rims throughout the upper meter of the sand rim (associated with archaeological deposits). Early Archaic and Paleoindian occupations are typically found no deeper than 1 meter (usually 80 cm or less) in bay sand rims. Deeper OSL (including basal) dates have been taken from bay sand rims at Big Bay, Mathis Pond, Flamingo Bay, and Johns Bay in order to establish the timing of rim formation. Most of these dates have been published in peer-reviewed articles (Brooks et al. 2010) in addition to being presented at numerous professional conferences.
Also, I really don’t appreciate the accusation that we selected bays to date that would somehow show what we want to find. Recent research at Flamingo Bay, Frierson Bay, and Johns Bay are scattered throughout the Central Savannah River Area, have diverse geomorphology including single bay rims, some with evidence of migration and others without, one is currently an open water bay, two are not. These bay were initially selected in order to gather archaeological data from bays over a wider area than the Savannah River Site. ALL of our recent OSL samples come directly from the sand rim. You are right, there are plenty of other bays that need research and dating…we are working on it. Two more basal OSL samples will be dated in the near future using single grain OSL.
Finally, with respect to the Goldsboro Scarp, similar landforms (with bays) can be seen on LiDAR data along most major rivers in North and South Carolina (Tar River for example northwest of Greenville). They are paleo-estuarine shorelines. The Suffolk Scarp is a major paleo-marine shoreline feature in eastern North Carolina (running north to south) from one of the last major sea-level transgressions. That “hill” is also covered with Carolina bays as are most other marine scarps. I would also like to see OSL dating of more of these landforms. On that point, we can agree
Chris –
Absolutely no response to any of the points I made about your pdfs?
Is this sweep bad news under the carpet time?
If a list of papers is your response, that is not a response. Those are YOUR pdfs, and nothing – as in zero – in them is new valid argument for lacustrine CB formation. And the only old argument is not your own.
Steve
“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.”
Exactly.
I do find it useful research that the fan experiment was done. Such controlled environment work is needed. That test gave no supportive data to the aeolian premise. If anything, it falsifies it – “No oval bay has points like that.” But it also seems to show, from your description, that aeolian cannot cause full 360° ovals.
Steve
Chris –
The only thing you addressed about my dissection of your pdfs was in your response to Michael:
“Also, I really don’t appreciate the accusation that we selected bays to date that would somehow show what we want to find.”
Your not appreciating it is not an argument or rebuttal.
I reiterate:
You chose three bays which all had at least 60% of their rims being more or less “normal”, yet:
1. In one you chose for transects the minor portion common and distorted by its merging with a second bay
2. In the other two you chose the clear minor portion immediately adjacent to the water ponded within the bay.
You being non-appreciative of me pointing out how those selections “just happened to” be best suited for your lacustrine arguments doesn’t address the issue.
P.S. If this is being over-combative, I can only say that if I chose only supportive locations for a field test, I would expect someone to challenge me on it. The funny thing is that I don’t think even those supported your lacustrine arguments. (See the balance of my dissection above…) All the lacustrine appears to be reworking of bays alreadty formed. (See your own clay bottom forms in your transects, and lack of strandlines therein.)
Whenever the CBs were formed, your work argues against lacustrine formation and only for lacustrine reworking.
Steve
Steve,
At this point, this discussion, while civil, had devolved into nonsense. Your opinions and interpretations notwithstanding on my research speak volumes about the fact that you have no supporting data for your own hypothesis. Eventually, you have to actually collect and present empirical data to support your ideas…just criticism of my research (and others) isn’t enough. Its not science, and frankly it seems more akin to attacks on evolution by creationists (i.e., teach the controversy and raise doubt, but don’t actually present any of your own data). We will be presenting and publishing new research over the next year. In the meantime, I will continue to do good science. If I see evidence for a non-lacustrine origin for bays, I will report it. Thus far, there are no data that contradict the general framework for bay formation and evolution understood since Kaczorowkis’s seminal work on bays in the late 70s. Again, the burden of evidence is not mine, but yours. Good luck.
Make sure to check out the new post with Davias presentation this week.
Chris, I asked clear questions and brought up clear objections to your assertions. I did not devolve into any nonsense. None of what I said was opinion. It was all observations on specifics.
I only ask that you address the specific technical points I brought up. You’ve made no effort at all so far.
Go back to my comment of April 2, 7:46pm, and please address the concerns. I don’t have to produce any alternative in order to ask questions or point out inconsistencies and apparent failures. I only ask that you clear up those points. You are free to rebut, and that is what I am asking for.
Chris –
“If I see evidence for a non-lacustrine origin for bays, I will report it.”
In those two pdfs, you have not produced any evidence FOR lacustrine origin for bays.
If you did, please point at it.
Chris –
George asked this question.
See the image at https://cosmictusk.com/wp-content/uploads/Goldsboro_Ridge_Profile.jpg
George’s question is this: “Goldsboro Ridge: How does a lake form on top of a hill?”
Hello Steve and all
Yes, that was the main question that made me travel more than 800km in 2009 to the interior of Brazil for a semi-arid region: a pond on a hill?
http://sites.google.com/site/cosmopier/impact-craters/end-pleistocene-palaeolagoons
Fortunately they were there: the impactites. In this region I also found evidence of their possible age: 12,900 years!
But depending on soil type, in other fields of ponds, is not always easy to find them.
http://sites.google.com/site/cosmopier/palaeometeorstream/impactites-tektites-meteorites
regards
pierson
Fair enough, Chris.
Mike, may I sgguest that you sample the areas immediately outside of the Bays and their rims? If the Bays were formed by secondary impacts, then there is likely to be tertiary ejecta deposits outside of them.
Godd luck to all in figuring out the Bays.
are you guys talking about what shaped those ovals?
if so then it’s just water and wind in the right medium I’m afraid. Go to 50 530916E 6303000S in Western Australia. We’ve got heaps of the suckers and as you can see they come about from water settlements on an almost flat plain with no geological activity for a thousand miles or a couple hundred million years. If you look close you can see how they reform and change size etc. with little ones lining the outside of some past larger ones.
hope that helps put it to rest for ya mate