None of these researchers have examined impact events at all, to my knowledge.
George, Bob, How about giving folks a link?
Hi Ed: Just a few items on impacts (though, this is as Ed points out correctly,is not my ballywick). I will submit something I know quite a bit more about and that is on meltwater soon. Most of what I have learned re: impacts is from Dr. William Napier, as well as some follow-up papers I obtained, as well. The great majority of encounters Earth has had over the past twenty thousand years or so appear to have been with what were, but no longer are, the Jupiter Family of comets. These are comets captured by the gas giant, but in this one case (the Taurids) they have escaped and taken up residence never that far from Earth. The encounters we are most likely to have are not with any of the large comet bodies per se (example comet Encke that is an object about five kilometres across) but with the associated meteor stream that surrounds such objects. And if this occurs, then Dr. Napier believes that the encounter will last close to two days. Thus, you can see the reason perhaps for the 12,900 BP event being spread over a significant portion of the globe. It is the nature of objects within the Taurid stream to be bolides (perhaps in some cases objects up to 500 metres across) to have a low angle of entry (this because their orbit around Earth is highly elliptical). The angles may in fact be as shallow as 30 degrees or less). Assuming I have got the details correct, I think that some of the impact discussion should concentrate on these types of encounters.
Hi Rod –
A big problem right now is that we don’t have a good estimate as to comet flux/asteroid flux, and if it varies, where we are in it.
My guess is that Bill Napier’s model for comet disintegration is pretty good, but another problem is we simply do not now know enough about the process in general, or the composition and formation of comets. It is almost certain that their cores are different than their surfaces.
Rod, I do not think we can generalize from the case of comet Encke anymore than we can generalize from the case of comet Biela.
The search for data on Encke’s impact sequence is still desperately going on, as you can see from the Holliday-Firestone interchange. Right now we don’t know with certainty if 10,900 BCE event was the first hit, or a later one.
I have little doubt that 60 meter comet fragments as dark as charcoal are probably the most difficult potential impactors to find, and are very dangerous.
If you haven’t taken a look at Comet Schwassmann Wachmann 3 yet, take a look.
I am looking forward to reading your piece on the outflows of Glacial Lake Agassiz, and the melt sequence for the ice packs.
Hello George, Grondine and all, thanks for all
The archaeoastronomy conference on Peru is already full with its schedule.
Last year I presented “The Event Tupana” on INFRAO/2009 in São Raimundo Nonato, and some research already initiated the first references of the rock paintings and prehistoric paintings themes. But most of them still focus on the possible symbolic interpretations for these abstract or geometric rock art theme.
My work is empirical and associate information obtained by morphological, structural and mineralogical analysis of craters or paleolagoons, as well as empirical models for the bolide trajectory, and the parallax of the sites of prehistoric records. Of course you must have a certain knowledge of astronomy. This is a multidisciplinary work,but interdisciplinarity is a necessity for any researcher and their search for objects with so many interfaces. I’m just trying to add a few.
Next year I plan to attend the XVI World Congress of UISPP (Brazil), where I hope to present a paper on (the paleolagoas) possible representations of meteoritic events in the U.S., South Africa, Brazil, England, using the same method of analysis, the parallax of the prehistoric observer’s local and its record (rock art) of the event.
In all these cases the meteoroids came from the southern hemisphere, at a low angle. In the case of palaeolagoons field on São Raimundo Nonato the age of 12,900 BP is consistent for this possible prehistoric event in this region.
Most of these things are spread out on my webpage. Archaeologists have been more interested than astronomers, for now. But over time this should change, soon. I finally beginning the research on the palaeolagoons last year (2009). Currently I participate in two pages of discussion in archeology.
You know, this research is not academic, I’m just an amateur astronomer, without financial resources to support such research, for now.
One thing has me intrigued: if those paleolagoons found around the world have a meteoric stream origin, we have to imagine that its projenitor comet should be of an unusual size.
regards for all
pierson
Hi Pierson,
Like those here in the American Southwest, most of the Palaeolagoons don’t fit the standard model of an impact structure. Since it’s the hyper-thermal shock wave that does the damage to the ground, and not the direct transfer of kinetic energy, the blast effected materials don’t necessarily include things like shocked grains, or even a crater. But the ground effects of an airburst, or ‘Air Hammer’ as Mark Boslough has called it, should still include significant siderophile, or platinum group element enrichment. Have you had a chance to have materials from some of those in South America tested?
Among millions, I chose 4 and visited 3 of these lpalaeolagoons, and in which I visited I found possible impactits.
Sure, the region’s geology help in the formation and identification of the material. The rock-based (crystalline) is shallow and the soil surface is very shallow, often the basement rocks outcrop.
Another palaeolagoon in the same area studied by paleontologists (2004), the oldest sediment of the pond appears to have more than 12,900 BP.
I have investigated following four criteria adopted by EDEIS: morphological, structural, mineralogical and chemical. The morphological and mineralogical criteria are to my immediate reach. The structural criteria some times I found relevant information. Since the chemical criterion is more difficult, I think the samples should be collected by professionals under the criteria adopted by them, so that data may have validity, and confirm the origin of cosmic structures. I do not stress about it.
The strategy at the moment is this: add enough information to add this view for palaeolagoons in studies’ research centers and universities, which have material conditions to investigate the chemical criteria in their own regions. And they can validate their own data, confirm or disprove the hypothesis. It can take years!
Last week arguing with my friend Cantarelli, he told me that in the paleolagoon Itaparica (6 km), Bahia (BR), it is possible with a magnet to collect pieces of iron.
Considering the hypothesis for a comet meteoroid (for this structure) rich in volatile materials and rocks, and low in iron, the justification for this found, could be cause the soil is rich in iron ore, and the meteoritic process. The shock wave and superheated plasma.
This could be impactits, not metorites. The melted rocks of this soil rich in iron ore may have created iron impactits (?). I never heard about it, maybe be the first impactites of this genre. Anyway I need a sample of this material, it may be quite important.
I agree. That place is very similar to some that are commonly found in New Mexico, and west Texas.
As I said, since the morphology doesn’t fit the standard model of an impact structure, the proof with be in detailed analysis of the chemistry, and isotope mix.
If there are ground effects at all, there should still be detectable levels of ET isotopes, and/or chemistry, in any melt, or blast effected materials, produced by the event. Even if an exploding fragment is completely vaporized, and 100% of its kinetic energy is converted to heat before it hits the ground, leaving no recognizable crater.
Hi for all
I mean: Another palaeolagoon, Quari lagoon (PI), in the same area of my investigation studied by paleontologists (2004), the oldest sediment of the pond appears to have NO more than 12,900 BP.
thanks
Hello Rod
I think the model, or what was observed, in the impacts occurring on Jupiter are somewhat different from that observed in the meteor hitting the Earth.
Often the Earth passes through streams of ancient comets. The time it takes to traverse this toroid of meteoroids varies from 40 to 30 days.
Therefore, if applied to this stream model (a crushed comet), the period of impacts may be greater than 2 days as the meteor showers observed today.
regards
pierson
Hello Rod
I think the model, or what was observed, in the impacts occurring on Jupiter are somewhat different from that observed in the meteor hitting the Earth.
Often the Earth passes through streams of ancient comets. The time it takes to traverse this toroid of meteoroids varies from 4 to 30 days.
Therefore, if applied to this stream model (a crushed comet), the period of impacts may be greater than 2 days as the meteor showers observed today.
regards
pierson
Hi Pierson: Yes, I agree that the Shoemaker-Levy 9 event at Jupiter was somewaht different than the major events that have affected our planet. Our planet when it encounters a meteor stream (not the whole comet as was the case with Shoemaker–Levy 9 at Jupiter) has what some astronomers (Napier, Clube, Asher and Steel for instance) call cosmic showers. These events are those where Earth encounters not the comet nucleus, but parts of the debris that make up the comet tail and the head of the comet, ie., the surrounding bolides,dust and debris. Some of these can be fairly significan objects up to hundreds of metres across. The Earth is because, of its atmosphere(and I suspect gravity) able to break the smaller objects, especially comets (as they are much less strongly configured as compared to asteroids. Hence,we have many airbursting events (Tunguska-like). The confusion I think I might have introduced, concerns what are called Jupiter family comets (these are comets captured by Jupiter). Shoemaker-Levy 9 was some of these though ever so briefly, but there are some others such as the Taurid Meteor Stream (Comet Encke is one of these objects) that then get nudged into the inner Solar System. As Earth encounters this stream from time to time, that is when we have what Dr. Napier and others refer to has comet showers (These asronomers believe that the likely duration of the events are over a couple of days. Furthermmore,these showers can occur very frequently, as often as annually.
also to you Ed: The reason comet Encke and the Taurid meteor stream is considered so prominent, is because at least in part, the feature that is known as the zodiacal cloud that resides here in the inner Solar system has been estimated as composed of up to 85% to 95 dust from Jupiter family comets (of which the Taurids were a part of until not that long ago). Finally for now Re: the meltwater questions, I am in the process of submitting a detailed review article to the Journal, Quaternary Science Reviews, that I hope will be accepted. When I have completed this process I will provide a summary to the very important meltwater issues. Some of this is already out there in my book that you have.
Dear Rod
Thak you
I agree “…Dr. Napier and others refer to has comet showers (These asronomers believe that the likely duration of the events are over a couple of days.”
Yes, I fully agree that this model is consistent to what I have observed from the rock art, and orientation of palaeolagoons. The meteors should come from the southern hemisphere in low zenith angle trajectory, the azimuth angle may be associated with the local time of the event, which may have occurred on a massive scale, in a few hours and simultaneously in various parts of the world.
regards
pierson
Hi Pierson: That is extremely interesting, the objects coming in from the Southern Hemisphere. Any thoughts if from the southwest, south or southeast? Either of these approaches would not be consistent with the Carolina Bays orientation that had the bolides arriving from the Northwest, at least not in the time frame we are talking about here (Younger Dryas and smaller events through the Holocene). Best wishes, Rod.
Pierson –
Do you know if ANY impact specialist is going to speak in Lima?
Has John Carlson’s journal “Archaeoastronomy” EVER published a piece on ancient impacts, and ancient comets?
Back to models of comet composition. From the Rio Curaca and Rupunini impact we can estimate that they were impacts of “cometissimals” roughly 30 m in diameter. Tunguska appears to have been around 60 m, though Boslough thinks less. That fragment had a long entry through the atmosphere.
What seems likely to me is that comets consolidate over time, with the heavier Platinum Group Elements “precipitating” or “condensing” towards their centers. My current guess is that the 30 m “cometissimals” conmbine chaotically, and that accounts for the variety of fragmentation patterns observed so far.
Title:
Impact Melt Formation by Low-Altitude Airburst Processes, Evidence from Small Terrestrial Craters and Numerical Modeling
Authors:
Newsom, H. E.; Boslough, M. B. E.
Publication:
39th Lunar and Planetary Science Conference, (Lunar and Planetary Science XXXIX), held March 10-14, 2008 in League City, Texas.
LPI Contribution No. 1391., p.1460
Publication Date: 03/2008
Origin: LPI
Bibliographic Code: 2008LPI….39.1460N
Impact melt formation by low-altitude airburst processes, evidence from small terrestrial craters and numerical modeling.
H. E. Newsom 1, and M. B. E. Boslough 2,
1 Univ. of New Mexico, Institute of Meteoritics,
MSC03-2050, Albuquerque, NM 87131, USA [email protected],
2 Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185
IMPACT MELT FORMATION BY LOW-ALTITUDE AIRBURST PROCESSES, EVIDENCE FROM SMALL TERRESTRIAL CRATERS AND NUMERICAL MODELING. H. E. Newsom1, and M. B. E. Bos-lough2, 1Univ. of New Mexico, Institute of Meteoritics, MSC03-2050, Albuquerque, NM 87131, USA [email protected], 2Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185
Introduction
Airbursts in the lower atmosphere from hypervelocity impacts have been called upon to explain the nature of the Tunguska event and the existence of unusual impact-related silicate melts such as the Muong-Nong tektites and Libyan Desert Glass of western Egypt [1].
Impact melts associated with impact craters, however, have been traditionally attributed to shock melting of the target material that experiences strong shock compression and heating.
The characteristics of impact melts from small terrestrial craters (< 4 km diameter) leads to the possibility that the airburst phenomena may have been responsible for these melts.
This conclusion is supported by numerical modeling of the airburst phenomena using super computer class facilities at Sandia National Laboratories [1].
Numerical modeling results
Recent models of the airburst phenomena have revealed several important insights into the coupling of the airburst with the surface and the possible nature of the resulting silicate melts.
The center of mass of an exploding projectile is transported downward in the form of a high-temperature jet of expanding gas (Fig. 1).
The jet descends by a significant fraction of the burst altitude before its velocity becomes subsonic.
The time scale of this descent is similar to the time scale of the explosion itself, so the jet simultaneously couples its kinetic energy and its internal energy to the atmosphere.
Because of this downward flow, larger blast waves and stronger thermal radiation pulses are felt at the surface than would be predicted by a point source explosion at the height where the burst was initiated.
For impacts with a kinetic energy above some threshold, the hot jet of vaporized projectile (the descending “fireball”) makes contact with the Earth’s surface, where it expands radially.
During the time of radial expansion, the fireball can maintain temperatures well above the melting temperature of silicate minerals, and its radial velocity can exceed the sound speed in air.
Boslough and Crawford [1] suggest that the surface materials can ablate by radiative/convective melting under these conditions, and then quench rapidly to form glass after the fireball cools and recedes.
For crater-forming impact events, the atmosphere also plays an important, if not dominant role.
The iron projectile that formed Meteor Crater (Arizona) deposited more than 2.5 times as much energy directly into the atmosphere than it carried to the surface [2].
Small crater-forming impacts should therefore exhibit phenomena similar to those associated with airbursts.
Impact melts from small terrestrial craters
Small craters with impact melt fragments include; Wabar, Aouelloul, Henbury, and Lonar.
The striking characteristics of the impact melt fragments from these craters is the presence of thin layers of melt.
These layers are sometimes isolated fragments (e.g. Aouelloul),
sometimes stacked into layered accumulations (Lonar),
and sometimes form coatings around unmelted material or layered melt bodies (Lonar).
The layered accumulations have much in common with the Muong-Nong type silicate melt materials.
Fig. 1, Airburst for which the fireball descends to the surface [1].
White = 5800 K; Red = 2000 K.
Bottom image shows wind speeds. Red represents supersonic flow.
[ Measuring the images shows that at 10 seconds,
the ground width of the burst is 13.4 km,
with round area 140 km**2,
while the central cone of ground excavation is deeper than 1/3 km. ]
Fig. 2, Samples of impact melt coating matrix from the Wabar impact crater in Saudi Arabia.
Image 6 cm width.
Materials from individual craters are described below, as a function of the diameter of the structure:
Wabar, Saudi Arabia, 0.12 km diameter, sedimentary target
The impact melt samples from this crater are unique in consisting of white material coated by dark impact melt [e.g. 3] (Fig. 2).
Henbury, Australia, 0.16 km diameter, sedimentary target
The Henbury impact structure consists of numerous small craters, with the largest being 0.16 km in diameter, ranging down to depressions only a few meters in diameter containing iron meteorite fragments [e.g. 4].
The Henbury craters reflect the disruption of the impactor at some significant altitude.
The Henbury samples in our collection have a distinct coating of melt in many cases (Fig. 3).
Evidence for high temperature gas flow rupturing vesicle walls in Henbury melt samples has also been reported [5].
Fig. 3, Impact melt clast (6 cm diameter) surface (left image) and cross section (right image) from Henbury, Australia.
Note the layered texture.
Aouelloul, Mauritania, 0.39 km diameter, sedimentary target
The Aouelloul impact crater contains impact melt fragments (Fig. 4).
Structure is a distinct impact crater with impact melt fragments [6].
Fig. 4, Impact melt fragments from Aouelloul (image 10 cm across).
The impact melts form layers placed on edge in the image, except for the sample on the bottom.
Lonar, India, 1.83 km diameter, basaltic target
The impact melt deposits described in this abstract (e.g., Fig. 5) come from the eastern rim of the impact crater, and are thought to represent the uppermost layer of ejecta [7-10].
The samples consist of layers of impact melt loosely organized into large coherent masses.
In some cases (not illustrated) the melt forms ropes and blobs like taffy, on a scale of a few mm.
The formation of the impact melt by an airburst, as opposed to shock melting, may be consistent with the limited evidence for hydrothermal processes in the ejecta blanket at Lonar [8] and the absence of abundant impact melt in the drill cores from the floor of the crater [9].
A similar sample has recently been found at the 4 km diameter Ramgarh structure [11].
Fig. 5, Impact melt bomb from the eastern side of the Lonar impact crater.
Note the layered texture of this sample. Width 6 cm.
Conclusions
Numerical modeling suggests that low altitude airbursts due to the interaction of hypervelocity projectiles with the atmosphere can produce surface melting forming thin layers as seen in the materials from Aouelloul.
The accompanying supersonic velocity flow field can redistribute the melted surface layer forming accumulations of layers as seen in the Muong-Nong tektites and some of the larger Lonar impact melt masses.
The ropy surface textures of some of the Lonar melts could result from transport of the melted layers.
The impact melt rinds found on samples from Wabar, Henbury and Lonar can be the result of melting due to incorporation of materials into the hot flow field, much like the fusion crust on meteorites.
References
[1] Boslough, M.B.E. and Crawford, D.A. (2007)
Int. J. Impact Eng., in press.
[2] Melosh, H.J. and Collins, G.S. (2005)
Nature, 434, 157.
[3] Shoemaker, E. M., and Wynn, J. C., (1997).
Lunar and Planetary Science XXVIII, pp. 1313-1314.
[4] Taylor, S. R. (1967)
Geochimica et Cosmochimica Acta, v. 31, pp. 961-968.
[5] C. Bender Koch (2007)
Geochimica et Cosmochimica Acta, 71, Suppl. 1, A48.
[6] Koeberl, C., Auer, P. (1991)
Lunar and Planetary Science XXII, pp. 731-732.
[7] Osae, S., Misra, S. , Koeberl, C. , Sengupta, D. and Ghosh, S. (2005)
Meteoritics & Planetary Science 40, Nr 9/10, P. 1473 – 1492.
[8] Newsom, H. E.; Misra, S.; Nelson, M. J. (2007)
Lunar and Planetary Sci. XXXVIII, abs. # 2056.
[9] Hagerty, J. J., and Newsom, H. E. (2003)
Meteoritics and Planet. Sci., 38, 365-381.
[10] Misra S. et al. (2006) LPSC 37th, abs. # 2123.
[11] Misra S. et al. (2007) LPSC 39th submitted.
Supported by NASA P.G.&G. NNG 05GJ42G (H. Newsom).
Sandia is operated by Sandia Corporation, a Lockheed Martin Company, for the United States Dept. of Energy under Contract DE-AC04-94AL85000.
The computational work was funded at Sandia by the LDRD and CSRF programs (M. Boslough).
[ Measuring the images shows that at 10 seconds,
the ground width of the burst is 13.4 km,
with round area 140 km**2,
while the central cone of ground excavation is deeper than 1/3 km. ]
Impact melt formation by low-altitude airburst processes, evidence from
small terrestrial craters and numerical modeling, H E Newsom & MBE Boslough
2008 Mar 2p abstract: Rich Murray 2010.11.17 http://rmforall.blogspot.com/2010_11_01_archive.htm
Wednesday, November 17, 2010
[ at end of each long page, click on Older Posts ] http://groups.yahoo.com/group/astrodeep/message/73
[you may have to Copy and Paste URLs into your browser]
Hi Grondine, Rod
The chemical composition of comets is well known, however its structure is still a mystery. But imagined that comets come from distant parts of the solar system, it is possible to imagine that its structure is a conglomerate of heterogeneous rocks of various sizes, dust, gases and water ice, slowly dissolving or subliming during passes near the Sun. It is possible that there are fragments of various compositions, sometimes rock, sometimes ice, sometimes mixed, differentiated by their density, these meteoroids with various sizes may cause different effects on the Earth’s surface.A fragment of ice with 50 m diameter should behave differently from one another rock fragment with 50 m during the shock.
What I noticed, based on the observed structure of craters (palaeolagoons), models and some rock art possibly associated with these events is that metoroides come from south. I tried to explain how in many fields of craters with different directions, southwest, south or southeast, they may originate from the same rain of meteoroids, coming from the southern hemisphere sky in parallel orbits within a toroid.
If the Carolina Bays originate from a meteor coming from the south, they would fit this model.
For me, one of the most curious filds are the elliptical and aligned structures found in Ohio and Florida (U.S.). The Great Serpent Mound geoglyph could be related whit this event. I applied an analysis of the local rock art parallax.
47.328431 27.987854 .282 km elevation of edge ridge,
.120 km above
.162 km el of W downhill side of the middle of three similar adjacent
craters in Moldova, each about 1 km wide.
The placemark is on the top of the sharp edge between the middle and N
crater, displaying bare white rock on its S slope,
very similar to the craters to its N and S.
This could be triple simultaneous airbursts — seemingly leaving many
of these “pawprint” features on the landscape.
Ed, I did link to Pierson’s site. Is that what you mean?
FYI, just spent a few days with Allen West. Some quite extraordinary things are going on about which Ill tell you one day. http://Www.nanodiamondtechnologies.com
Hi George: I do hope you might share the info you learned from Allen West, with the rest of us too!!!!! Or is the cosmic tusk becoming an exclusive club too? I really think that some of these guys are almost as bad the non impact believers!! Just because I am not part of this establishmnet I think I desrve to be in the loop as much as others. So George?
I’m sympathetic, Rod. And I hate to tease you. West and I have started a company and it’s gonna be big for the whole subject….but business is business and the time is not yet ripe for disclosure. I do have a nice pic of us at the airport I plan to post.
Hi Rod –
Aside from business considerations, one needs to keep in mind the first publication requirements of many academic publications in one’s public remarks.
Sorry Fellows (ED and George); I did not realise it was a business venture. I have been frustrated in the past not hearing back from a number of scientists (not yourselves I might add) but people like Dr. Firestone and Dr. West for instance. I know they are very busy, but I regard it is as simple common courtesy to respond to any sincere inquiry. Just a little frustrated at how difficult it is to get the word out there via my book etc, I guess. Cheers, and good luck in your venture!
Hi Rod –
I’m sure George will tell you that both Firestone and West are extremely busy, as is the rest of their team. There is also that problem of first publication which they face.
I’m looking forward to reading your Agassiz drainage study.
Hi Ed: I understand! And I will soon be able to write something on the “Agassiz” situation. It will be a synthesis of a part of my submission (that I hope will be accepted) by the Journal, “Quaternary Science Reviews.” It is not too much different than the part concerned meltwater drainages I wrote about in my book you have. But I will be happy to write something here at the Cosmic Tusk too.
Your comment is awaiting moderation.
November 17th, 2010 at 8:33 am
Hi Grondine, Rod
The chemical composition of comets is well known, however its structure is still a mystery. But imagined that comets come from distant parts of the solar system, it is possible to imagine that its structure is a conglomerate of heterogeneous rocks of various sizes, dust, gases and water ice, slowly dissolving or subliming during passes near the Sun. It is possible that there are fragments of various compositions, sometimes rock, sometimes ice, sometimes mixed, differentiated by their density, these meteoroids with various sizes may cause different effects on the Earth’s surface.A fragment of ice with 50 m diameter should behave differently from one another rock fragment with 50 m during the shock.
What I noticed, based on the observed structure of craters (palaeolagoons), models and some rock art possibly associated with these events is that metoroides come from south. I tried to explain how in many fields of craters with different directions, southwest, south or southeast, they may originate from the same rain of meteoroids, coming from the southern hemisphere sky in parallel orbits within a toroid.
If the Carolina Bays originate from a meteor coming from the south, they would fit this model.
For me, one of the most curious filds are the elliptical and aligned structures found in Ohio and Florida (U.S.). The Great Serpent Mound geoglyph could be related whit this event. I applied an analysis of the local rock art parallax.
Anyway, other fields of craters may have origin in other streams of meteoroids.
best regards
pierson
Rod, thanks for your kind words. A quick side note that I have been meaning to pass on to you and others for some time. Firestone is mentioned far to often in Tusk posts and comments, relative to his time “under the hood” of the research today. He is a hero for taking the research up from William Topping 2001, and to collaborate with West and others since, but the fact is he contributes little to the research today (but does talk a lot to the press which is understandable, if not always helpful). I know Firestone personally, have traveled with him, and like the hell out of him. But the (totally justified) mis-perception is that he and West lead this effort today. Not true. Is is more accurately West and Kennett (and Kennett, Jr) and a host of others that chip in (including Rick at times). I have a draft blog on this subject, but just haven’t finished it. I guess this is it, huh?
As for not hearing back from correspondence, keep in mind that all these guys who are “part” of the YD team, me included, get a lot email on the subject, with varying degrees of time to respond appropriately. Allen West gets a ton, but has a ton more that needs immediate attention from other researchers with important physical field results. I know for a fact if you have field results and send them to Allen he will engage at length with you.
It is hard to be patient with these type things. You are always welcome to post a “Guest Blog” here, too, Rod. For better or worse it does get people’a attention! Take care.
Hi Pierson –
(just call me “EP”)
Serpent Mound is the remains of a structure built by the Andaste people around 900 BCE. This structure was later modified by the Tchalagi (ancestral to Cherokee and Tchalga division Shawnee) about 100 CE.
Myself and my colleague Fletcher Wilson (one of Ohio’s leading naked eye astronomers) have written an initial guide to Serpent Mound, which is in the process of being updated for new information recovered from Putnam’s excavation reports by Jeff Wilson, one of Ohio’s leading archaeologists.
I have recovered petroglyphs in North America showing impacts, but their context has been lost and they are undatable (right now, anyhow). Their parallax has been lost as well.
As always, more money would make the work far easier.
Hi George: Thank-you for your reply and explanation too. Though I have not been in contact with Dr. Kennett Jr., I did send a copy (again free to Dr. Kennett Sr.). Though he did not provide any supportive comments like Dr. Napier, Dr. Bas van Geel and a few others (said it is not his policy to do so) he did seem to enjoy reading it. As I said it is my main desire to get the book out there (and your website has helped with this), even if it means providing my book free of charge. So if you have any further suggestions in this regard, I would like to hear them. And thank-you for your offer of a another blog, I may well do so soon. I am presently trying to have the journal- Quaternary Science Reviews include a recent submission I made to them, that attempted to provide an overview of the Younger Dryas. So when that is finalized one way or another I will write another blog. E.P. seems to want to see my take on meltwater fluxes around the time of the Younger Dryas, so this is a possibility.
Hi Pierson: Could you please explain (perhaps it is my misconception) how the Carolina Bays that are orientated northwest to southeast (with what I thought was the lee side of all the elliptical forms) fit with the model of bolides coming in for the south?
Hi Rod
As I have observed in some craters (Panela, Ascension Crater – Devil’s Riding School, Ohio/Wilmington/Field/Serpent Mound, Chenko/Tunguska, Rio Cuarto, South Africa field), based on some the parallax of the local rock art and geometry of the craters, I find that the field of the Carolina Bays should not be an exception in the context of the Holocene and the End-Pleistocene massive common cosmic event.
Anyway, we should also consider the myth of Phaeton’s ride (Kobres) as another accurate description of the same cosmic phenomenon.
Admitting a date earlier than 14,000 years for this event … a comet coming from the north celestial hemisphere, coming from the constellation of Ursa Major, breaking down by gravity of Earth, in a close encounter of almost shock, an Earth missing encounter, most of the its pieces continued to orbit to the sides of the south Solar System, in the direction to the constellation of Eridanus.
Yes, at this time (> 14.000 BP) the direction of meteoroids coming from the northern hemisphere may cause structures oriented from northeast to southwest or northwest to southeast, symmetrically to meteoroids coming from the southern hemisphere sky.
I believe that the deflection of the orbit of this comet shattered in this event before its perihelion, it should have triggered in a second moment shock even more intense, a mass meeting with debris after the perihelion, somewhat similar to the deflection caused by Jupiter in the orbit of comet P/Shoemaker-Levy 9, when the comet came from the north celestial hemisphere.
Now (<14,000 BP), in the second moment the intersection of shock to Earth's orbit with the torus of meteoroids that come from the south celestial hemisphere (as the fragments of the comet P/Shoemaker-Levy 9 that hit Jupiter, which also came from the south) can cause structures oriented southeast to northwest, or sometimes from southwest to northeast.
But I consider that in some structures that I looked, even superficially, the model of meteoroids coming from the north celestial hemisphere seems to apply, and appear to originate from the first meeting, before the perihelion.
[ The next two posts on rmforall.blogspot.com give in time order 1 and 2–12 1 MG jpg photos of the rock via 3.2 MPx BlackBerry cell phone, with 3 sequences of closeups — also on Photos for AstroDeep at Yahoo Groups. ]
As two scientific scouts, Michael Barron and I enjoyed the
92 mile drive Tuesday Nov. 9 from Santa Fe to Vaughn
to check on many craters listed by Dennis Cox,
and more that we had found with Google Earth and Maps.
His Garmin GPS unit gave locations, while I took
a few dozen BlackBerry 3.2 MPx photos of sites there,
and, without crossing fences, we were able to collect
many samples, which we hope to offer for free to
capable experts for analysis.
This introductory report is to be helpful for anyone
who wants to enjoy a preliminary practical guide
for many research opportunities….
Hello to all
Have you seen? Possible cosmic event in the Holocene. Would it have been global event of falling fragments? I always have the impression that the palaeolagoons that I have investigated are quite recent.
38 Responses
Splendid work you are doing, Pierson.
Will you be able to attend the archaeoastronomy conference which will be held in Lima, Peru in January?:
http://www1.archaeoastronomy.org/
None of these researchers have examined impact events at all, to my knowledge.
George, Bob, How about giving folks a link?
Hi Ed: Just a few items on impacts (though, this is as Ed points out correctly,is not my ballywick). I will submit something I know quite a bit more about and that is on meltwater soon. Most of what I have learned re: impacts is from Dr. William Napier, as well as some follow-up papers I obtained, as well. The great majority of encounters Earth has had over the past twenty thousand years or so appear to have been with what were, but no longer are, the Jupiter Family of comets. These are comets captured by the gas giant, but in this one case (the Taurids) they have escaped and taken up residence never that far from Earth. The encounters we are most likely to have are not with any of the large comet bodies per se (example comet Encke that is an object about five kilometres across) but with the associated meteor stream that surrounds such objects. And if this occurs, then Dr. Napier believes that the encounter will last close to two days. Thus, you can see the reason perhaps for the 12,900 BP event being spread over a significant portion of the globe. It is the nature of objects within the Taurid stream to be bolides (perhaps in some cases objects up to 500 metres across) to have a low angle of entry (this because their orbit around Earth is highly elliptical). The angles may in fact be as shallow as 30 degrees or less). Assuming I have got the details correct, I think that some of the impact discussion should concentrate on these types of encounters.
Hi Rod –
A big problem right now is that we don’t have a good estimate as to comet flux/asteroid flux, and if it varies, where we are in it.
My guess is that Bill Napier’s model for comet disintegration is pretty good, but another problem is we simply do not now know enough about the process in general, or the composition and formation of comets. It is almost certain that their cores are different than their surfaces.
Rod, I do not think we can generalize from the case of comet Encke anymore than we can generalize from the case of comet Biela.
The search for data on Encke’s impact sequence is still desperately going on, as you can see from the Holliday-Firestone interchange. Right now we don’t know with certainty if 10,900 BCE event was the first hit, or a later one.
I have little doubt that 60 meter comet fragments as dark as charcoal are probably the most difficult potential impactors to find, and are very dangerous.
If you haven’t taken a look at Comet Schwassmann Wachmann 3 yet, take a look.
I am looking forward to reading your piece on the outflows of Glacial Lake Agassiz, and the melt sequence for the ice packs.
Hello George, Grondine and all, thanks for all
The archaeoastronomy conference on Peru is already full with its schedule.
Last year I presented “The Event Tupana” on INFRAO/2009 in São Raimundo Nonato, and some research already initiated the first references of the rock paintings and prehistoric paintings themes. But most of them still focus on the possible symbolic interpretations for these abstract or geometric rock art theme.
My work is empirical and associate information obtained by morphological, structural and mineralogical analysis of craters or paleolagoons, as well as empirical models for the bolide trajectory, and the parallax of the sites of prehistoric records. Of course you must have a certain knowledge of astronomy. This is a multidisciplinary work,but interdisciplinarity is a necessity for any researcher and their search for objects with so many interfaces. I’m just trying to add a few.
Next year I plan to attend the XVI World Congress of UISPP (Brazil), where I hope to present a paper on (the paleolagoas) possible representations of meteoritic events in the U.S., South Africa, Brazil, England, using the same method of analysis, the parallax of the prehistoric observer’s local and its record (rock art) of the event.
In all these cases the meteoroids came from the southern hemisphere, at a low angle. In the case of palaeolagoons field on São Raimundo Nonato the age of 12,900 BP is consistent for this possible prehistoric event in this region.
Most of these things are spread out on my webpage. Archaeologists have been more interested than astronomers, for now. But over time this should change, soon. I finally beginning the research on the palaeolagoons last year (2009). Currently I participate in two pages of discussion in archeology.
You know, this research is not academic, I’m just an amateur astronomer, without financial resources to support such research, for now.
One thing has me intrigued: if those paleolagoons found around the world have a meteoric stream origin, we have to imagine that its projenitor comet should be of an unusual size.
regards for all
pierson
Hi Pierson,
Like those here in the American Southwest, most of the Palaeolagoons don’t fit the standard model of an impact structure. Since it’s the hyper-thermal shock wave that does the damage to the ground, and not the direct transfer of kinetic energy, the blast effected materials don’t necessarily include things like shocked grains, or even a crater. But the ground effects of an airburst, or ‘Air Hammer’ as Mark Boslough has called it, should still include significant siderophile, or platinum group element enrichment. Have you had a chance to have materials from some of those in South America tested?
Here’s a paper that might be applicable.
Impact melt formation by low-altitude airburst processes, evidence from small terrestrial craters and numerical modeling by H. E. Newsom, M. B. E Boslough
Hi Dennis
Not yet.
Among millions, I chose 4 and visited 3 of these lpalaeolagoons, and in which I visited I found possible impactits.
Sure, the region’s geology help in the formation and identification of the material. The rock-based (crystalline) is shallow and the soil surface is very shallow, often the basement rocks outcrop.
Another palaeolagoon in the same area studied by paleontologists (2004), the oldest sediment of the pond appears to have more than 12,900 BP.
I have investigated following four criteria adopted by EDEIS: morphological, structural, mineralogical and chemical. The morphological and mineralogical criteria are to my immediate reach. The structural criteria some times I found relevant information. Since the chemical criterion is more difficult, I think the samples should be collected by professionals under the criteria adopted by them, so that data may have validity, and confirm the origin of cosmic structures. I do not stress about it.
The strategy at the moment is this: add enough information to add this view for palaeolagoons in studies’ research centers and universities, which have material conditions to investigate the chemical criteria in their own regions. And they can validate their own data, confirm or disprove the hypothesis. It can take years!
Last week arguing with my friend Cantarelli, he told me that in the paleolagoon Itaparica (6 km), Bahia (BR), it is possible with a magnet to collect pieces of iron.
Considering the hypothesis for a comet meteoroid (for this structure) rich in volatile materials and rocks, and low in iron, the justification for this found, could be cause the soil is rich in iron ore, and the meteoritic process. The shock wave and superheated plasma.
This could be impactits, not metorites. The melted rocks of this soil rich in iron ore may have created iron impactits (?). I never heard about it, maybe be the first impactites of this genre. Anyway I need a sample of this material, it may be quite important.
I need to visit this region!
http://maps.google.com.br/maps?t=f&ecpose=-11.05636808,-42.76313897,31321.09,-0.191,0,0&lci=com.panoramio.all&ie=UTF8&ll=-11.056368,-42.763139&spn=0.206551,0.307274&z=12
regards
pierson
Thanks Pierson,
I agree. That place is very similar to some that are commonly found in New Mexico, and west Texas.
As I said, since the morphology doesn’t fit the standard model of an impact structure, the proof with be in detailed analysis of the chemistry, and isotope mix.
If there are ground effects at all, there should still be detectable levels of ET isotopes, and/or chemistry, in any melt, or blast effected materials, produced by the event. Even if an exploding fragment is completely vaporized, and 100% of its kinetic energy is converted to heat before it hits the ground, leaving no recognizable crater.
Hi for all
I mean: Another palaeolagoon, Quari lagoon (PI), in the same area of my investigation studied by paleontologists (2004), the oldest sediment of the pond appears to have NO more than 12,900 BP.
thanks
Hello Rod
I think the model, or what was observed, in the impacts occurring on Jupiter are somewhat different from that observed in the meteor hitting the Earth.
Often the Earth passes through streams of ancient comets. The time it takes to traverse this toroid of meteoroids varies from 40 to 30 days.
Therefore, if applied to this stream model (a crushed comet), the period of impacts may be greater than 2 days as the meteor showers observed today.
regards
pierson
Hello Rod
I think the model, or what was observed, in the impacts occurring on Jupiter are somewhat different from that observed in the meteor hitting the Earth.
Often the Earth passes through streams of ancient comets. The time it takes to traverse this toroid of meteoroids varies from 4 to 30 days.
Therefore, if applied to this stream model (a crushed comet), the period of impacts may be greater than 2 days as the meteor showers observed today.
regards
pierson
Hi Pierson: Yes, I agree that the Shoemaker-Levy 9 event at Jupiter was somewaht different than the major events that have affected our planet. Our planet when it encounters a meteor stream (not the whole comet as was the case with Shoemaker–Levy 9 at Jupiter) has what some astronomers (Napier, Clube, Asher and Steel for instance) call cosmic showers. These events are those where Earth encounters not the comet nucleus, but parts of the debris that make up the comet tail and the head of the comet, ie., the surrounding bolides,dust and debris. Some of these can be fairly significan objects up to hundreds of metres across. The Earth is because, of its atmosphere(and I suspect gravity) able to break the smaller objects, especially comets (as they are much less strongly configured as compared to asteroids. Hence,we have many airbursting events (Tunguska-like). The confusion I think I might have introduced, concerns what are called Jupiter family comets (these are comets captured by Jupiter). Shoemaker-Levy 9 was some of these though ever so briefly, but there are some others such as the Taurid Meteor Stream (Comet Encke is one of these objects) that then get nudged into the inner Solar System. As Earth encounters this stream from time to time, that is when we have what Dr. Napier and others refer to has comet showers (These asronomers believe that the likely duration of the events are over a couple of days. Furthermmore,these showers can occur very frequently, as often as annually.
also to you Ed: The reason comet Encke and the Taurid meteor stream is considered so prominent, is because at least in part, the feature that is known as the zodiacal cloud that resides here in the inner Solar system has been estimated as composed of up to 85% to 95 dust from Jupiter family comets (of which the Taurids were a part of until not that long ago). Finally for now Re: the meltwater questions, I am in the process of submitting a detailed review article to the Journal, Quaternary Science Reviews, that I hope will be accepted. When I have completed this process I will provide a summary to the very important meltwater issues. Some of this is already out there in my book that you have.
Dear Rod
Thak you
I agree “…Dr. Napier and others refer to has comet showers (These asronomers believe that the likely duration of the events are over a couple of days.”
Yes, I fully agree that this model is consistent to what I have observed from the rock art, and orientation of palaeolagoons. The meteors should come from the southern hemisphere in low zenith angle trajectory, the azimuth angle may be associated with the local time of the event, which may have occurred on a massive scale, in a few hours and simultaneously in various parts of the world.
regards
pierson
Hi Pierson: That is extremely interesting, the objects coming in from the Southern Hemisphere. Any thoughts if from the southwest, south or southeast? Either of these approaches would not be consistent with the Carolina Bays orientation that had the bolides arriving from the Northwest, at least not in the time frame we are talking about here (Younger Dryas and smaller events through the Holocene). Best wishes, Rod.
Pierson –
Do you know if ANY impact specialist is going to speak in Lima?
Has John Carlson’s journal “Archaeoastronomy” EVER published a piece on ancient impacts, and ancient comets?
Back to models of comet composition. From the Rio Curaca and Rupunini impact we can estimate that they were impacts of “cometissimals” roughly 30 m in diameter. Tunguska appears to have been around 60 m, though Boslough thinks less. That fragment had a long entry through the atmosphere.
What seems likely to me is that comets consolidate over time, with the heavier Platinum Group Elements “precipitating” or “condensing” towards their centers. My current guess is that the 30 m “cometissimals” conmbine chaotically, and that accounts for the variety of fragmentation patterns observed so far.
http://dl.dropbox.com/u/2268163/IMPACT%20MELT%20FORMATION%20BY%20LOW-ALTITUDE%20AIRBURST%20PROCESSES,.pdf
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1460.pdf free full-text
Title:
Impact Melt Formation by Low-Altitude Airburst Processes, Evidence from Small Terrestrial Craters and Numerical Modeling
Authors:
Newsom, H. E.; Boslough, M. B. E.
Publication:
39th Lunar and Planetary Science Conference, (Lunar and Planetary Science XXXIX), held March 10-14, 2008 in League City, Texas.
LPI Contribution No. 1391., p.1460
Publication Date: 03/2008
Origin: LPI
Bibliographic Code: 2008LPI….39.1460N
http://adsabs.harvard.edu/abs/2008LPI….39.1460N find similar articles in database
Lunar and Planetary Science XXXIX (2008) 1460.pdf
Impact melt formation by low-altitude airburst processes, evidence from small terrestrial craters and numerical modeling.
H. E. Newsom 1, and M. B. E. Boslough 2,
1 Univ. of New Mexico, Institute of Meteoritics,
MSC03-2050, Albuquerque, NM 87131, USA [email protected],
2 Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185
IMPACT MELT FORMATION BY LOW-ALTITUDE AIRBURST PROCESSES, EVIDENCE FROM SMALL TERRESTRIAL CRATERS AND NUMERICAL MODELING. H. E. Newsom1, and M. B. E. Bos-lough2, 1Univ. of New Mexico, Institute of Meteoritics, MSC03-2050, Albuquerque, NM 87131, USA [email protected], 2Sandia National Laboratories, PO Box 5800, Albuquerque, NM 87185
Introduction
Airbursts in the lower atmosphere from hypervelocity impacts have been called upon to explain the nature of the Tunguska event and the existence of unusual impact-related silicate melts such as the Muong-Nong tektites and Libyan Desert Glass of western Egypt [1].
Impact melts associated with impact craters, however, have been traditionally attributed to shock melting of the target material that experiences strong shock compression and heating.
The characteristics of impact melts from small terrestrial craters (< 4 km diameter) leads to the possibility that the airburst phenomena may have been responsible for these melts.
This conclusion is supported by numerical modeling of the airburst phenomena using super computer class facilities at Sandia National Laboratories [1].
Numerical modeling results
Recent models of the airburst phenomena have revealed several important insights into the coupling of the airburst with the surface and the possible nature of the resulting silicate melts.
The center of mass of an exploding projectile is transported downward in the form of a high-temperature jet of expanding gas (Fig. 1).
The jet descends by a significant fraction of the burst altitude before its velocity becomes subsonic.
The time scale of this descent is similar to the time scale of the explosion itself, so the jet simultaneously couples its kinetic energy and its internal energy to the atmosphere.
Because of this downward flow, larger blast waves and stronger thermal radiation pulses are felt at the surface than would be predicted by a point source explosion at the height where the burst was initiated.
For impacts with a kinetic energy above some threshold, the hot jet of vaporized projectile (the descending “fireball”) makes contact with the Earth’s surface, where it expands radially.
During the time of radial expansion, the fireball can maintain temperatures well above the melting temperature of silicate minerals, and its radial velocity can exceed the sound speed in air.
Boslough and Crawford [1] suggest that the surface materials can ablate by radiative/convective melting under these conditions, and then quench rapidly to form glass after the fireball cools and recedes.
For crater-forming impact events, the atmosphere also plays an important, if not dominant role.
The iron projectile that formed Meteor Crater (Arizona) deposited more than 2.5 times as much energy directly into the atmosphere than it carried to the surface [2].
Small crater-forming impacts should therefore exhibit phenomena similar to those associated with airbursts.
Impact melts from small terrestrial craters
Small craters with impact melt fragments include; Wabar, Aouelloul, Henbury, and Lonar.
The striking characteristics of the impact melt fragments from these craters is the presence of thin layers of melt.
These layers are sometimes isolated fragments (e.g. Aouelloul),
sometimes stacked into layered accumulations (Lonar),
and sometimes form coatings around unmelted material or layered melt bodies (Lonar).
The layered accumulations have much in common with the Muong-Nong type silicate melt materials.
Fig. 1, Airburst for which the fireball descends to the surface [1].
White = 5800 K; Red = 2000 K.
Bottom image shows wind speeds. Red represents supersonic flow.
[ Measuring the images shows that at 10 seconds,
the ground width of the burst is 13.4 km,
with round area 140 km**2,
while the central cone of ground excavation is deeper than 1/3 km. ]
Fig. 2, Samples of impact melt coating matrix from the Wabar impact crater in Saudi Arabia.
Image 6 cm width.
Materials from individual craters are described below, as a function of the diameter of the structure:
Wabar, Saudi Arabia, 0.12 km diameter, sedimentary target
The impact melt samples from this crater are unique in consisting of white material coated by dark impact melt [e.g. 3] (Fig. 2).
Henbury, Australia, 0.16 km diameter, sedimentary target
The Henbury impact structure consists of numerous small craters, with the largest being 0.16 km in diameter, ranging down to depressions only a few meters in diameter containing iron meteorite fragments [e.g. 4].
The Henbury craters reflect the disruption of the impactor at some significant altitude.
The Henbury samples in our collection have a distinct coating of melt in many cases (Fig. 3).
Evidence for high temperature gas flow rupturing vesicle walls in Henbury melt samples has also been reported [5].
Fig. 3, Impact melt clast (6 cm diameter) surface (left image) and cross section (right image) from Henbury, Australia.
Note the layered texture.
Aouelloul, Mauritania, 0.39 km diameter, sedimentary target
The Aouelloul impact crater contains impact melt fragments (Fig. 4).
Structure is a distinct impact crater with impact melt fragments [6].
Fig. 4, Impact melt fragments from Aouelloul (image 10 cm across).
The impact melts form layers placed on edge in the image, except for the sample on the bottom.
Lonar, India, 1.83 km diameter, basaltic target
The impact melt deposits described in this abstract (e.g., Fig. 5) come from the eastern rim of the impact crater, and are thought to represent the uppermost layer of ejecta [7-10].
The samples consist of layers of impact melt loosely organized into large coherent masses.
In some cases (not illustrated) the melt forms ropes and blobs like taffy, on a scale of a few mm.
The formation of the impact melt by an airburst, as opposed to shock melting, may be consistent with the limited evidence for hydrothermal processes in the ejecta blanket at Lonar [8] and the absence of abundant impact melt in the drill cores from the floor of the crater [9].
A similar sample has recently been found at the 4 km diameter Ramgarh structure [11].
Fig. 5, Impact melt bomb from the eastern side of the Lonar impact crater.
Note the layered texture of this sample. Width 6 cm.
Conclusions
Numerical modeling suggests that low altitude airbursts due to the interaction of hypervelocity projectiles with the atmosphere can produce surface melting forming thin layers as seen in the materials from Aouelloul.
The accompanying supersonic velocity flow field can redistribute the melted surface layer forming accumulations of layers as seen in the Muong-Nong tektites and some of the larger Lonar impact melt masses.
The ropy surface textures of some of the Lonar melts could result from transport of the melted layers.
The impact melt rinds found on samples from Wabar, Henbury and Lonar can be the result of melting due to incorporation of materials into the hot flow field, much like the fusion crust on meteorites.
References
[1] Boslough, M.B.E. and Crawford, D.A. (2007)
Int. J. Impact Eng., in press.
[2] Melosh, H.J. and Collins, G.S. (2005)
Nature, 434, 157.
[3] Shoemaker, E. M., and Wynn, J. C., (1997).
Lunar and Planetary Science XXVIII, pp. 1313-1314.
[4] Taylor, S. R. (1967)
Geochimica et Cosmochimica Acta, v. 31, pp. 961-968.
[5] C. Bender Koch (2007)
Geochimica et Cosmochimica Acta, 71, Suppl. 1, A48.
[6] Koeberl, C., Auer, P. (1991)
Lunar and Planetary Science XXII, pp. 731-732.
[7] Osae, S., Misra, S. , Koeberl, C. , Sengupta, D. and Ghosh, S. (2005)
Meteoritics & Planetary Science 40, Nr 9/10, P. 1473 – 1492.
[8] Newsom, H. E.; Misra, S.; Nelson, M. J. (2007)
Lunar and Planetary Sci. XXXVIII, abs. # 2056.
[9] Hagerty, J. J., and Newsom, H. E. (2003)
Meteoritics and Planet. Sci., 38, 365-381.
[10] Misra S. et al. (2006) LPSC 37th, abs. # 2123.
[11] Misra S. et al. (2007) LPSC 39th submitted.
Supported by NASA P.G.&G. NNG 05GJ42G (H. Newsom).
Sandia is operated by Sandia Corporation, a Lockheed Martin Company, for the United States Dept. of Energy under Contract DE-AC04-94AL85000.
The computational work was funded at Sandia by the LDRD and CSRF programs (M. Boslough).
a convenient, readable plain text version:
http://dl.dropbox.com/u/2268163/IMPACT%20MELT%20FORMATION%20BY%20LOW-ALTITUDE%20AIRBURST%20PROCESSES,.pdf
http://www.lpi.usra.edu/meetings/lpsc2008/pdf/1460.pdf free full-text
[ Measuring the images shows that at 10 seconds,
the ground width of the burst is 13.4 km,
with round area 140 km**2,
while the central cone of ground excavation is deeper than 1/3 km. ]
Impact melt formation by low-altitude airburst processes, evidence from
small terrestrial craters and numerical modeling, H E Newsom & MBE Boslough
2008 Mar 2p abstract: Rich Murray 2010.11.17
http://rmforall.blogspot.com/2010_11_01_archive.htm
Wednesday, November 17, 2010
[ at end of each long page, click on Older Posts ]
http://groups.yahoo.com/group/astrodeep/message/73
[you may have to Copy and Paste URLs into your browser]
Hi Grondine, Rod
The chemical composition of comets is well known, however its structure is still a mystery. But imagined that comets come from distant parts of the solar system, it is possible to imagine that its structure is a conglomerate of heterogeneous rocks of various sizes, dust, gases and water ice, slowly dissolving or subliming during passes near the Sun. It is possible that there are fragments of various compositions, sometimes rock, sometimes ice, sometimes mixed, differentiated by their density, these meteoroids with various sizes may cause different effects on the Earth’s surface.A fragment of ice with 50 m diameter should behave differently from one another rock fragment with 50 m during the shock.
What I noticed, based on the observed structure of craters (palaeolagoons), models and some rock art possibly associated with these events is that metoroides come from south. I tried to explain how in many fields of craters with different directions, southwest, south or southeast, they may originate from the same rain of meteoroids, coming from the southern hemisphere sky in parallel orbits within a toroid.
Please take a look at the pages:
http://sites.google.com/site/cosmopier/impact-craters/palaeolagoon-geometry
If the Carolina Bays originate from a meteor coming from the south, they would fit this model.
For me, one of the most curious filds are the elliptical and aligned structures found in Ohio and Florida (U.S.). The Great Serpent Mound geoglyph could be related whit this event. I applied an analysis of the local rock art parallax.
Please take a look at the pages:
http://sites.google.com/site/cosmopier/impact-craters/holocene-palaeolagoons
What do you think?
Anyway, other fields of craters may have origin in other streams of meteoroids.
best regards
pierson
3 adjacent 1 km craters in Moldova, NW of the Black Sea — possible Holocene
air bursts: Rich Murray 2010.11.18
http://rmforall.blogspot.com/2010_11_01_archive.htm
Thursday, November 18, 2010
[ at end of each long page, click on Older Posts ]
http://groups.yahoo.com/group/astrodeep/message/77
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47.328431 27.987854 .282 km elevation of edge ridge,
.120 km above
.162 km el of W downhill side of the middle of three similar adjacent
craters in Moldova, each about 1 km wide.
The placemark is on the top of the sharp edge between the middle and N
crater, displaying bare white rock on its S slope,
very similar to the craters to its N and S.
This could be triple simultaneous airbursts — seemingly leaving many
of these “pawprint” features on the landscape.
Ed, I did link to Pierson’s site. Is that what you mean?
FYI, just spent a few days with Allen West. Some quite extraordinary things are going on about which Ill tell you one day. http://Www.nanodiamondtechnologies.com
Hi George: I do hope you might share the info you learned from Allen West, with the rest of us too!!!!! Or is the cosmic tusk becoming an exclusive club too? I really think that some of these guys are almost as bad the non impact believers!! Just because I am not part of this establishmnet I think I desrve to be in the loop as much as others. So George?
I’m sympathetic, Rod. And I hate to tease you. West and I have started a company and it’s gonna be big for the whole subject….but business is business and the time is not yet ripe for disclosure. I do have a nice pic of us at the airport I plan to post.
Hi Rod –
Aside from business considerations, one needs to keep in mind the first publication requirements of many academic publications in one’s public remarks.
Sorry Fellows (ED and George); I did not realise it was a business venture. I have been frustrated in the past not hearing back from a number of scientists (not yourselves I might add) but people like Dr. Firestone and Dr. West for instance. I know they are very busy, but I regard it is as simple common courtesy to respond to any sincere inquiry. Just a little frustrated at how difficult it is to get the word out there via my book etc, I guess. Cheers, and good luck in your venture!
Hi Rod –
I’m sure George will tell you that both Firestone and West are extremely busy, as is the rest of their team. There is also that problem of first publication which they face.
I’m looking forward to reading your Agassiz drainage study.
Hi Ed: I understand! And I will soon be able to write something on the “Agassiz” situation. It will be a synthesis of a part of my submission (that I hope will be accepted) by the Journal, “Quaternary Science Reviews.” It is not too much different than the part concerned meltwater drainages I wrote about in my book you have. But I will be happy to write something here at the Cosmic Tusk too.
Your comment is awaiting moderation.
November 17th, 2010 at 8:33 am
Hi Grondine, Rod
The chemical composition of comets is well known, however its structure is still a mystery. But imagined that comets come from distant parts of the solar system, it is possible to imagine that its structure is a conglomerate of heterogeneous rocks of various sizes, dust, gases and water ice, slowly dissolving or subliming during passes near the Sun. It is possible that there are fragments of various compositions, sometimes rock, sometimes ice, sometimes mixed, differentiated by their density, these meteoroids with various sizes may cause different effects on the Earth’s surface.A fragment of ice with 50 m diameter should behave differently from one another rock fragment with 50 m during the shock.
What I noticed, based on the observed structure of craters (palaeolagoons), models and some rock art possibly associated with these events is that metoroides come from south. I tried to explain how in many fields of craters with different directions, southwest, south or southeast, they may originate from the same rain of meteoroids, coming from the southern hemisphere sky in parallel orbits within a toroid.
Please take a look at the pages:
http://sites.google.com/site/cosmopier/impact-craters/palaeolagoon-geometry
If the Carolina Bays originate from a meteor coming from the south, they would fit this model.
For me, one of the most curious filds are the elliptical and aligned structures found in Ohio and Florida (U.S.). The Great Serpent Mound geoglyph could be related whit this event. I applied an analysis of the local rock art parallax.
Please take a look at the pages:
http://sites.google.com/site/cosmopier/impact-craters/holocene-palaeolagoons
What do you think?
Anyway, other fields of craters may have origin in other streams of meteoroids.
best regards
pierson
Rod, thanks for your kind words. A quick side note that I have been meaning to pass on to you and others for some time. Firestone is mentioned far to often in Tusk posts and comments, relative to his time “under the hood” of the research today. He is a hero for taking the research up from William Topping 2001, and to collaborate with West and others since, but the fact is he contributes little to the research today (but does talk a lot to the press which is understandable, if not always helpful). I know Firestone personally, have traveled with him, and like the hell out of him. But the (totally justified) mis-perception is that he and West lead this effort today. Not true. Is is more accurately West and Kennett (and Kennett, Jr) and a host of others that chip in (including Rick at times). I have a draft blog on this subject, but just haven’t finished it. I guess this is it, huh?
As for not hearing back from correspondence, keep in mind that all these guys who are “part” of the YD team, me included, get a lot email on the subject, with varying degrees of time to respond appropriately. Allen West gets a ton, but has a ton more that needs immediate attention from other researchers with important physical field results. I know for a fact if you have field results and send them to Allen he will engage at length with you.
It is hard to be patient with these type things. You are always welcome to post a “Guest Blog” here, too, Rod. For better or worse it does get people’a attention! Take care.
Hi Pierson –
(just call me “EP”)
Serpent Mound is the remains of a structure built by the Andaste people around 900 BCE. This structure was later modified by the Tchalagi (ancestral to Cherokee and Tchalga division Shawnee) about 100 CE.
Myself and my colleague Fletcher Wilson (one of Ohio’s leading naked eye astronomers) have written an initial guide to Serpent Mound, which is in the process of being updated for new information recovered from Putnam’s excavation reports by Jeff Wilson, one of Ohio’s leading archaeologists.
I have recovered petroglyphs in North America showing impacts, but their context has been lost and they are undatable (right now, anyhow). Their parallax has been lost as well.
As always, more money would make the work far easier.
Hi George: Thank-you for your reply and explanation too. Though I have not been in contact with Dr. Kennett Jr., I did send a copy (again free to Dr. Kennett Sr.). Though he did not provide any supportive comments like Dr. Napier, Dr. Bas van Geel and a few others (said it is not his policy to do so) he did seem to enjoy reading it. As I said it is my main desire to get the book out there (and your website has helped with this), even if it means providing my book free of charge. So if you have any further suggestions in this regard, I would like to hear them. And thank-you for your offer of a another blog, I may well do so soon. I am presently trying to have the journal- Quaternary Science Reviews include a recent submission I made to them, that attempted to provide an overview of the Younger Dryas. So when that is finalized one way or another I will write another blog. E.P. seems to want to see my take on meltwater fluxes around the time of the Younger Dryas, so this is a possibility.
Hi Pierson: Could you please explain (perhaps it is my misconception) how the Carolina Bays that are orientated northwest to southeast (with what I thought was the lee side of all the elliptical forms) fit with the model of bolides coming in for the south?
Hi Rod
As I have observed in some craters (Panela, Ascension Crater – Devil’s Riding School, Ohio/Wilmington/Field/Serpent Mound, Chenko/Tunguska, Rio Cuarto, South Africa field), based on some the parallax of the local rock art and geometry of the craters, I find that the field of the Carolina Bays should not be an exception in the context of the Holocene and the End-Pleistocene massive common cosmic event.
Anyway, we should also consider the myth of Phaeton’s ride (Kobres) as another accurate description of the same cosmic phenomenon.
Admitting a date earlier than 14,000 years for this event … a comet coming from the north celestial hemisphere, coming from the constellation of Ursa Major, breaking down by gravity of Earth, in a close encounter of almost shock, an Earth missing encounter, most of the its pieces continued to orbit to the sides of the south Solar System, in the direction to the constellation of Eridanus.
Yes, at this time (> 14.000 BP) the direction of meteoroids coming from the northern hemisphere may cause structures oriented from northeast to southwest or northwest to southeast, symmetrically to meteoroids coming from the southern hemisphere sky.
I believe that the deflection of the orbit of this comet shattered in this event before its perihelion, it should have triggered in a second moment shock even more intense, a mass meeting with debris after the perihelion, somewhat similar to the deflection caused by Jupiter in the orbit of comet P/Shoemaker-Levy 9, when the comet came from the north celestial hemisphere.
Now (<14,000 BP), in the second moment the intersection of shock to Earth's orbit with the torus of meteoroids that come from the south celestial hemisphere (as the fragments of the comet P/Shoemaker-Levy 9 that hit Jupiter, which also came from the south) can cause structures oriented southeast to northwest, or sometimes from southwest to northeast.
But I consider that in some structures that I looked, even superficially, the model of meteoroids coming from the north celestial hemisphere seems to apply, and appear to originate from the first meeting, before the perihelion.
Some illustration are on my pages
https://sites.google.com/site/cosmopier/impact-craters/holocene-palaeolagoons?pli=1
https://sites.google.com/site/cosmopier/palaeometeorstream
https://sites.google.com/site/cosmopier/impact-craters/palaeolagoon-geometry
regards
pierson
unique erratic 3 m rock, complex mixed composition, and many possibly related airburst features W of Vaughn, New Mexico: Dennis Cox: Rich Murray 2010.11.26
http://rmforall.blogspot.com/2010_11_01_archive.htm
Friday, November 26, 2010
[ at end of each long page, click on Older Posts ]
http://groups.yahoo.com/group/astrodeep/message/78
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[ The next two posts on rmforall.blogspot.com give in time order 1 and 2–12 1 MG jpg photos of the rock via 3.2 MPx BlackBerry cell phone, with 3 sequences of closeups — also on Photos for AstroDeep at Yahoo Groups. ]
As two scientific scouts, Michael Barron and I enjoyed the
92 mile drive Tuesday Nov. 9 from Santa Fe to Vaughn
to check on many craters listed by Dennis Cox,
and more that we had found with Google Earth and Maps.
His Garmin GPS unit gave locations, while I took
a few dozen BlackBerry 3.2 MPx photos of sites there,
and, without crossing fences, we were able to collect
many samples, which we hope to offer for free to
capable experts for analysis.
This introductory report is to be helpful for anyone
who wants to enjoy a preliminary practical guide
for many research opportunities….
Hello to all
Have you seen? Possible cosmic event in the Holocene. Would it have been global event of falling fragments? I always have the impression that the palaeolagoons that I have investigated are quite recent.
http://www.knowledgeminer.eu/climate/papers.html
http://www.knowledgeminer.eu/climate/pdf/H1.pdf
rigards
pierson
Hi George
There was a loss of your old scribd deleted link, follows a link to the article about rock art and Panela crater.
http://www.fumdham.org.br/fumdhamentos_9/Artigo18%20IFRAO2009.pdf
regards
pierson