From UC-Davis:
Rock soil droplets formed by heating most likely came from Stone Age house fires and not from a disastrous cosmic impact 12,900 years ago, according to new research from the University of California, Davis. The study, of soil from Syria, is the latest to discredit the controversial theory that a cosmic impact triggered the Younger Dryas cold period.
The Younger Dryas lasted a thousand years and coincided with the extinction of mammoths and other great beasts and the disappearance of the Paleo-Indian Clovis people. In the 1980s, some researchers put forward the idea that the cool period, which fell between two major glaciations, began when a comet or meteorite struck North America.
In the new study, published online in the Journal of Archaeological Science, scientists analyzed siliceous scoria droplets — porous granules associated with melting — from four sites in northern Syria dating back 10,000 to 13,000 years ago. They compared them to similar scoria droplets previously suggested to be the result of a cosmic impact at the onset of the Younger Dryas.
“For the Syria side, the impact theory is out,” said lead author Peter Thy, a project scientist in the UC Davis Department of Earth and Planetary Sciences. “There’s no way that can be done.”
The findings supporting that conclusion include:
- The composition of the scoria droplets was related to the local soil, not to soil from other continents, as one would expect from an intercontinental impact.
- The texture of the droplets, thermodynamic modeling and other analyses showed the droplets were formed by short-lived heating events of modest temperatures, and not by the intense, high temperatures expected from a large impact event.
- And in a key finding, the samples collected from archaeological sites spanned 3,000 years. “If there was one cosmic impact,” Thy said, “they should be connected by one date and not a period of 3,000 years.”
So if not resulting from a cosmic impact, where did the scoria droplets come from? House fires. The study area of Syria was associated with early agricultural settlements along the Euphrates River. Most of the locations include mud-brick structures, some of which show signs of intense fire and melting. The study concludes that the scoria formed when fires ripped through buildings made of a mix of local soil and straw.
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“… the cool period, which fell between two major glaciations,…”
Wasn’t the end of the Y-D is considered the start of the Holocene.?
Good point. It should read something like “the cool period, which interrupted the gradual warming taking place at the end of the last Ice Age”, or something like that.
I wonder if they will, eventually, disprove the asteroid theory and show somehow that CO2 raised over 400ppm and that is what killed the dinosaurs
Francisco:
The Team has already tried to blame CO2 for past mass extinctions, including the Triassic-Jurassic event, which actually benefited dinosaurs at the expense of competing groups, & the previous Great Dying at the Permian-Triassic boundary, which enabled their early evolution. And the Carbonari Mafia also tend to prefer more late Mesozoic volcanic CO2 to or in addition to the Cretaceous-Tertiary mass extinction event impact hypothesis.
So your joke is sadly real.
the absence of evidence is not the evidence of absence
Actually recognizing the absence of evidence can reduce the likelihood of choosing an explanation for which there is actually no recognizable evidence.
I cite , Sherlock Holmes , the dog that did not bark.
Indeed; Fitzroy Simpson was not the culprit.
How does one sustain “intense fire and melting” in a mud-brick structure?
Look, I just ask the questions…
I guess you could set the roof on fire.
Don’t forget the straw in the bricks!
Mud brick is largely straw.
Thats not what I learned by reading “The Three Little Pigs”
The wolf’s oxygen input by huffing and puffing made the straw in the mud brick burn hot enough to melt silica? A wolf driven kiln? There’s a dirty panting joke in there somewhere I just can’t tease out.
Sounds like a straw man argument.
Just ask The Talking Heads.
ConTrari:
Something learned in engineering school in the late 60’s. Timber frame buildings will last longer in a fire than steel. The steel will deform and collapse. Big wood timbers char on the outside and prevent the interior wood from burning. Of course, you can’t build as big as steel and concrete, but one reason old wood buildings would survive. Not sure about today’s wood buildings with metal connectors though.
The Crystal Palace in London , built for the Great Exhibition of 1851 was constructed of glass and cast iron. It burned down , completely , 80 years later . Always wondered about that.
Must have been something combustible inside…iron will be disfigured at high temperatures, actuelly more so than solid wood structures.
looked that up – it had old, dried out timber flooring, plus it had been loaded up with flammable items. And of course, there was no such thing as a sprinkle system in those days.
Remember that our civilization is built on paper. It burns.
@wws
Perforated pipe sprinkler systems were being installed in the US by a predecessor to Grinnell in 1850; the concept originated in England in 1812. In 1812, the Theatre Royal was covered by such a system. In 1860 a patent was issued for the first fusible link device recognizable as a sprinkler.
So, had they chosen, the builders of The Crystal Palace could easily have installed or retrofitted a sprinkler system to provide fire protection.
Cast iron burns real gud if you have some oxygen around. IANAW but I have seen them cut big holes in iron with a “cutting torch”. Ordinary sparklers for Guy Fawkes Day, are just iron wire.
I once set fire to the iron alloy leads of a TO5 power transistor, by “overdissipating” it, till it got hot enough to torch the leads. It was an RCA transistor, and after it cooled down, the transistor chip inside the can was still perfectly good. That was circa 1963.
I had replaced a crummy Germanium transistor in a high Voltage power supply for a Tektronix transistorized oscilloscope (model 321 portable), with the RCA silicon one.
Unfortunately the RCA was also a good high frequency transistor, as well as high power compared to the Ge one.
So the transistor ignored the low frequency inductive coupling through the transformer ferrite core, and just used the air core coupling between the transformer windings, sans the core (the core was still there just being ignored at the high oscillator frequency it preferred.) Thing got so darn hot, the transistor leads caught fire, which also shut off the circuit. Shouldn’t meddle with things you don’t yet understand !!
Did get it working eventually, just by learning some things. I separated the feedback winding of the transformer, and stuck it on a separate leg of the ferrite core, so the only way it could oscillate was by using the magnetic coupling through the core, which forced it to run at the proper frequency.
g
george,
Interesting story, as usual. Thanks.
Aluminum burns really well – big fear for those aluminum frigates. When aluminum is more widely used in automobiles, we’ll see some really big sparkers. As for steel, it will burn as well in the right conditions.
http://www.airproducts.com/~/media/Files/PDF/industries/metals-discussion-steel-burning-oxygen-steelmaking-metallurgist-perspective.pdf
http://www.bbc.co.uk/bang/handson/steel_wool.shtml
Wayn,
Already long a problem for aluminum helicopters, fixed wing aircraft, armored personnel carriers like M113 & infantry fighting vehicles lie Bradley.
Wooden floors
Well, yeah, most any pure metal will burn, but it’s an issue of surface-area presented (toss steel-wool into a fire & watch). An aluminum strut will burn w/difficulty, but powder it & you’ve got solid-rocket fuel.
My thanks to all here (and downthread) for related comments on this. Comments were funny, interesting and enlightening.
I’d write more but my back yard is on fire…
The grass roots are acting like straw!
Tar was used to line the vessels used to store liquids and food stuff. It may have been used in other ways. Also, some of the vessels would have been used to store cooking and lighting oil? Also, what others said to your question.
Brick ovens of this type:
http://www.essenceoftheages.com/incienso/horno2.jpg
Fuel is continuously added. Eventually, the oven brick decomposes and the structure has to be replaced. An ordinary campfire might produce much the same effect if banked with soil.
Many of the houses had open areas. That region of the world was advanced in metallurgy.
In many places in the world there are the remains of where they smelted Iron and then made steel most often identifiable by the slag from the process which was waste of no value. Charcoal was used to reach the temperatures necessary and to provide the carbon needed to create steel from iron. Some of these places are still recognizable in deserts and savannahs where man used up the trees for wood and changed the ecology. The fact is that back when Iron and then steel were made in those mud/brick ovens the operations to move to places where the wood fuel necessary for the process was available.
Interesting article that shows how things aren’t always melodramatic in life! I hate to be picky, but that artist’s impression, whilst very pretty, assumes a 90° impact to the Earth’s surface, an unlikely situation in practice, me thinks! Similarly, in whichever of those disaster movies (the one with Maximillian Schell is the one that springs to mind) in which a comet/asteroid collided with the Earth, the movie even showed the comet/asteroid passing at an angle in the atmosphere, yet when it impacted, the graphics special effects guys showed a similar impact explosion, whereas it should have shown the blast directed across the Atlantic toward Europe, with a likely smaller wave heading back toward America!
Actually, simultions indicate that, except for extreme low angle impacts, the ecplosion is relatively symmetrical.
Meteor Crater in Arizona is probably an example of that.
Simulations? Models.
The final impact is probably modeled quite well, but not the passage through the atmosphere. Remember the Chelyabinsk meteorite, or the Columbia space shuttle.
Exactly right. Those simulations are backed up by actual crater counting on the Moon and other solar system celestial objects. Thus there is experimental evidence to back up these models. If you are interested in learning more google the name “Jay Melosh” who is one of the world experts in this field.
There’s Tunguska, which is supposed to be an airburst / glancing angle atmospheric event. NASA’s gas guns and Sandia Nat’l Labs also do quite a bit of high velocity impact testing and that data was used to build their models. You’ve got to know how that MIRV is going to act on re-entry or particle impacts on spacecraft.
Alan, why are almost all of the craters on the moon round?
Because the moon’s surface is a diffuse reflecting surface, not a billiard table bumper.
The “hole in the ground” is not the hole that the projectile made on impact, it is the hole made by the resulting explosive cataclysm, and that is quite axi-symmetrical. Does anybody really know at what angle the pebble that created Meteor crater in Arizona, struck the surface. The hole is at least 100 times the diameter of the pebble that made it.
G
The light scattered off fresh snow, is total independent of the incident sun angle, at least up to the Brewster angle.
Good point! has big rethink on statement! 😉
The study area of Syria was associated with early agricultural settlements along the Euphrates River.
==============
why study an area that has been disturbed by settlements? If micro-diamonds and other impact objects were present in the area, they would be present in the undisturbed soils. by picking an area that was contaminated by settlements, the researchers cannot place any confidence in their results.
In this particular case & study, the researchers are confirming a hypothesis about spherule or scoria formation, from the burning of settlements (and perhaps other human-combustion processes in the same area). Besides, they probably already doubted that spherule-drift & deposition occurred over vast areas. Thirdly, there is real value in establishing the presence & pattern of such special settlements-deposits, since at the end of the Bronze Age an apocolyptic settlement-burning event terminated that cultural era and set the stage for the subsequent emergence of Classical Civilation, in Europe. Over 90% of settlements were burned aggressively in this single great social convulsion, about which most questions await answers.
But more generally, yes, absolutely, the way to check out the idea of an early Holocene asteroid/comet strike is to look for spherules etc in geological horizons away from known archaeological sites. Such as in bog & lake sediments, and in settings were wind-blown dusts are known to have been lain down & preserved (which discribes vast areas of Midwest USA). Yet, proponents of the YD impact themselves have consistently restricted their inspections to Clovis cultural sites … leaving themselves open to this counter-suggestion – and evidence – that actually the spherules could have resulted from human-activity.
Good point … but more a problem for supporters, than for critics.
Dang those pesky tectites.
@Richard Dupuis K
January 7, 2015 at 5:57 am
How does one sustain “intense fire and melting” in a mud-brick structure?
Look, I just ask the questions…
Could it have been from the remnants of an early furnace for metal working? I would be surprised if an open domestic fire could produce sufficient heat to create the scoria!
How does one sustain “intense fire and melting” in a mud-brick structure?
=====================
Silicon dioxide
Melting point 1,600 to 1,725 °C (2,912 to 3,137 °F; 1,873 to 1,998 K)
http://en.wikipedia.org/wiki/Silicon_dioxide
The average house fire burns at a temperature of about 1,100 degrees Fahrenheit, which isn’t hot enough to destroy most metals and earthly-made substances. And if an item is well-placed and small in size, its chances of survival increase drastically.
http://www.live-safe.org/tag/fire-loss/
While silicon dioxide is a very common mineral, there are many others. Mud brick, adobe do contain SO2, but it serves mainly as a bulking-agent or filler, and is not the component that gives these structural materials their key properties.
Clays are essential to such bricks, and as exhibited in pottery and other fired materials, they sag and melt at much lower temperatures. A hot cooking oven will suffice for some pottery.
Fluxing agents and catalysts are critical in many pottery and metallurgical technologies. These serve to lower the melting temperature of minerals and metals. Ash from fires is a strong flux; burnt lime (bones & shells, and whitewashes for painting mud-daub walls) is used as a bulk fluxing agent. Fluxes (like lime itself) are often relatively soluble, and subsequently leach from materials they helped to form.
Salts are also strong fluxes, but they usually ‘damage’ a material intended to have structural properties. In Nature, though, any place that accumulates salts, such as arid lands or landlocked watersheds, will tend to exhibited the effects of salt-fluxing, under any kind of fire-regime. Salt-minerals also readily leach.
SO₂ is a gas. You mean SiO₂.
I did mean SiO₂, thank you! And SO₂ is an actor in these processes, in its own right.
How does one distinguish house fires from lightening strikes?
They are both small and localised.
The debris from an astronomical impact should be far easier to distinguish without using settlement history.
What’s a “lightening” strike? Please illuminate me. 😉
It’s like a lightning strike but misspelt.
Sigh, I’ll have to hand back my cheque from Big Oil now.
@M Courtney: is that check smaller then the postal stamp? do not insure the mail it’ll save some money!
I like it. Lightning has explosive force that would distribute any molten materials over a much wider area than house fires.
Not so much. Actually lightning forms silica tubes in plain sand. I have also been told it causes erosion of rock which may eject material but I doubt very far. Struck trees may have portions of the wood explode outward apparently from the sudden generation of steam, but again not driven so far. A friend’s house was struck and he reported that everything that had a transformer in it exploded or burnt. I doubt that a mud hut would generate any sort of explosion. Earth with organic material,when struck, gets really hot as I have observed it directly, which could theoretically generate some molten material. It certainly has no problem starting fires.
Libyan desert glass (LDG), or great sand sea glass is a substance found in areas in the Libyan Desert. Fragments of desert glass can be found over large areas, up to tens of kilometers.
The origin of the glass is a controversial issue for the scientific community, with many evolving theories.
http://en.wikipedia.org/wiki/Libyan_desert_glass
add house fires to the list.
… but they’re never going to get as many theories as Trenberth’s missing heat has.
Very interesting deposits, these glasses in the Sahara! And some of them seem like rather pure silicon dioxide, which takes very high temps.
A problem is that ‘typically’, natural glasses are not especially durable, across geological spans (10s of millions years, as some say of Libyan etc desert-glass). But to the extend these are made from pure quartz sand, maybe that’s a different thing.
I favor unknown or unrecognized or sporadic/episodic lightning phenomena, as the source of these glasses (rather than a big ET strike) … but when the hostilities cool off, maybe we can get some effective investigation going on in this region.
I like the theory that LDG is castings from giant sandworms…
Horsetail has this same metabolic faculty. Too bad we can’t get Frank on the Mars advisory board.
Interesting take and to expand on it. what happens to airborne silica sand during a lightning strike? Those plasma temps are certainly hot enough and that would also explain the distribution over a wide area. Might be an interesting avenue of research for a Master’s thesis (assuming no one’s done it.) I’d need to see the experimental data that says this can happen in “normal” fires with plant material as fuel… I don’t really buy that one.
The debris from an astronomical impact should be far easier to distinguish without using settlement history.
================
exactly. why use an area contaminated by human settlement? You might be seeing melted silica from pottery kilns and/or copper smelting. house fires are not hot enough to melt silica. to then jump to the conclusion that since these objects are the result of human activity, similar objects in areas where there are no settlements must also be a result of human activity is false logic.
Forget silica, it’s a white herring. 😉
Bronze smelting really only began around 2000BC, although in roughly the right area. Before that, even copper smelting started about 6000 years ago, with lead smelting (not hot enough anyway) possibly slightly before that, but not 12,900 years ago. Roof fires are a possibility, but probably not hot enough before they burn out. Simple fire pits are the most likely explanation, kept burning for long periods of time, possibly years, because fire was not easy to generate. The contents would be spread over the millennia.
@ur momisugly Peter_S January 7, 2015 at 6:20 am
“Bronze smelting really only began around 2000BC, although in roughly the right area. Before that, even copper smelting started about 6000 years ago, with lead smelting (not hot enough anyway) possibly slightly before that, but not 12,900 years ago. ”
Times are really changing Peter. History is being revised with all the new data… it is quite likely that smeling and metal work began over 12000 years agao. In the next 5 years you will hear more and more and the dates for the beginning of civilization will be pushed many thousands of years. It’s an exciting age we live in.
http://www.philipcoppens.com/gobekli.html
http://www.dartmouth.edu/~toxmetal/toxic-metals/more-metals/copper-history.html
pocketsponsor –
Do you happen to notice that all of those dates are at least 3,000 years AFTER the start of the Younger Dryas (which is also the start of the Holocene)?
No one here has picked up on the fact that none of this development – INCLUDING HOUSES – is at least 1,000 years after the Younger Dryas start?
You can’t burn houses 13,000 years ago if houses don’t exist yet.
one can imagine future archaeologists, digging up the remains of a modern city destroyed by nuclear war or comet impact. and finding large quantities of melted glass, they would conclude this was a result of intense heat of the buildings burning. from this they would then conclude that the melted glass in the Libyan desert must also be a result of human activity.
I have seen that conclusion in speculative history books. I did not know there was a mundane explanation. Now that I have seen one, house fires, etc. seem a more believable explanation than a prehistoric nuclear war.
Early nuclear bomb tests in Nevada etc, detonated on towers not very far off the ground, created layers of this often greenish glass on the ground surrounding the burst. People shortly made the connection with Saharan glasses … and the ancient or alien nuke war meme got started.
Depending on what the bomb was, and what the glassified soil was, it’s fairly easy to analyze the material and make – or break – a nuke fireball connection.
“Trinitite”, bomb-glass from New Mexico, acquired commercial value, for collectors. Some then made ‘fake’ Trinitite, but simple tests soon showed the difference, even when hoaxers included fairly elaborate ‘recipes’ of radioactive minerals, to make the stuff sound good under a Geiger counter.
How mud houses burn:
The hamlet in question, is a mixed hunter and farmers. By beeing farmers over generations, they have discovered that mixing the stalks from grain, reduces the need for mud in the bricks, it reduces both weight and drying time. Letting them build both faster and bigger structures.
Along the sides of the houses, straw or wood roofing would be built, to shade the ones slaughtering last nights kills. This has been done in the same place for generations, also blood from animals has been used to waterproof the straw/clay bricks also for generations. Adding fat and other organics to the brick mix.
Then a few years of unusual dry weather, the buildings dry up, in places the straw is all that holds the powdered clay/mud together.
Then the heard of some hunted animal return, there is a good hunt and a following feast. The wind blows some ambers onto the exposed straw. And the now, what was once a hamlet, but through generations have grown to a small village. Explosively erupts in flame, leaving only half told tales of angry animal gods and melted droplets of clay.
Repeat, repeat, repeat…
Spelling isn’t your strong suit, is it.
Maybe English ain’t their first language ?
How does your Chinese, Arabic or Japanese translate ?
You do keep us on our toes though.
please contribute something of substance. this isn’t a spelling forum.
Grammar is Finn’s problem here and it is mostly because there are periods where commas belong and commas in strange places. There are no spelling problems at all. The problem could even be translation software. It doesn’t slow down the reading and we get a new perspective on the article. Save the wise cracks for Trolls.
you feel proud of that statement?
When you educate yourself in a foreign language and take the pain of learning vocabulary, obscure grammatics and even more obscure spelling at age of ten or later (try yourself inflecting umtwana in plural, explain ablaut and umlaut, then maybe try classifying sibilants in modern Chinese), the last thing you want to hear is you are using translation software. Really.
English has certain difficult features. One is use of articles – but easy for most European language users. One is prepositions. It is easy to miss one or use a wrong one. Spelling is hard, but learnable. Pronunciation is harder than spelling – many learning English as a foreign language learn by writing and never quite learn how the words are said.
The easy part in English is its lack of inflection. Words like nonbespectacledly are not ruining life. It lacks complicated gender rules, like German (am Main, but an der Oder). It has only little posh exceptions like datum – data. The tonal structure is bearable and writing requires only little more letters than Romans used.
The language police strike again .
Close enough for climate work.
If the commenter is Finnish, as his screen name may suggest. then I think his English is remarkably good. No need for comments such as yours.
Why would you need to “slaughter” a “kill”? It’s already dead. Just asking…
Yes … yes, even today, we have awful explosions in grain-elevators, big storage bins for harvested grains. The ‘fuel’ for these explosions is nothing but bits of organic chaff and grass-plant parts … but finely-divided, mixed with air, and ka-BOOOMMM.
“Conditions” for & of fires do count. Old-time mud-brick settlements had their liabilities … and at times their misfortunes would be truly spectacular. We have these unusual fires to thank, for a lot of unusual preservation contexts that thrill archaeologists, and students.
One study says that mammoths survived until 7,600 years ago.
http://www.livescience.com/9771-mammoths-alive-thought.html
My memory cells have rattled slightly. Was there not a BBC Horizon programme years back looking at the disappearing Mammoth issue, which concluded that they may have remained around until relatively recently, certainly in Siberia? Anyway, that was back in the day when the Horizon prog was a real science show! Sadly it has gone the way much of the BBC stuff has gone!
Dwarf woollies survived on Wrangel Island off eastern Siberia until about 3600 years ago.
There is no evidence supporting an impact event as cause for the YD. Indeed there is no reason to look for an unusual cause in the first place, ie to reject null hypothesis, The YD was no different from the prior two Dryas events or the similar excursion c. 8200 years ago. The same patterns occur during other transitions from glacial to interglacial phases. The Dryases are also akin to Heinrich Events during glacial phases.
The Ivory Tower at it’s best: Syria sits squarely on top of the list of regions in the world which were earliest in developing pottery and metallurgy and, afterwards, entertained both for thousands of years to come – therefore, it’s the LEAST suited area to base a model on studying naturally occurring siliceous scoria droplets on, because the samples taken thereare tainted with droplets of uncertain origin up to the brim. Just a little more knowledge in human history would have saved the University of California’s day with a snap. But nooooo…
Simple fire pits are the most likely explanation
============
the problem is generating a high enough temperature, which required the invention of something like the chimney or bellows to force air through the coals. a pit fire likely limits combustion by using up the available air. technology is required to feed air into the bottom of the pit. something like a mud brick tunnel built up the slope of a hill.
Perhaps?
http://www.naturalbuildingblog.com/rocket-stove-with-oven/
To make charcoal, place wood nicely in the pit (or just in a mound on the ground), and then cover it with a layer of soil and sod, and even a daubed layer of clay-mud. Now the heat cannot escape easily, and temperatures will rise very high, with only a small air-supply and a modest rate of combustion. ‘Bank’ the heat in … that’s the origin of the word ‘bank’ … build the mound against a bank, and cover it to hold in the heat.
The making of charcoal leads to occasional ‘accidents’, the result of which is often extreme temperatures … and fascinating new materials and substances to find in the cooled ash-heap.
Cosmic impact, extinctions, etc. are strawmen erected for this inconsequential study to blow down. Not worth the attention of a gnat.
The actual article is paywalled, but here is a link to the abstract:
http://www.sciencedirect.com/science/article/pii/S0305440314004403
Main thrust appears to be that the scoria droplets can form at modest temperatures below 1200 C.
Were the authors able to create scoria droplets from a brick straw fire?
sco·ri·a
/ˈskôrēə/
noun
noun: scoria; plural noun: scoriae
a cindery, vesicular basaltic lava, typically having a frothy texture.
slag separated from molten metal during smelting.
Scoria Substitutes
Where scoria is not available a lightweight aggregate can be produced by heating shale in a rotating kiln under controlled conditions. With the proper type of shale the material will have the properties, appearance and vesicles of scoria. It is sold under the name “expanded aggregate”, “expanded clay” or “grow rocks” and used for the same purposes as crushed scoria.
http://geology.com/rocks/scoria.shtml
The full paper is at http://cosmictusk.com/wp-content/uploads/2015-01-Thy-SLO-paper.pdf
Re-posting this link as it is relevant to the discussion:
https://cometstorm.wordpress.com/2011/04/27/a-different-kind-of-climate-catastrophe-2/
The author did a yeoman’s job of fleshing out his version of the impact hypothesis. I have issues with his ideas about impacts forming the Carolina Bays, but the rest I think he is on the right track with everything else.
Pragmatically, the Younger Dryas Impact Hypothesis IS the Carolina Bays Impact Hypothesis.
Look up ‘carolina bays’. Hundreds of thousands of oriented elliptical depressions & lakes, spread over a large quadrant of the eastern USA. This is a truly amazing phenomenon. Hair-raising, even. ‘What on earth are these things … are they even Earthly at all!?”
Carolina Bays fascination amped-up sensationally, with the advent of the airplane … whereupon the full scale & scope of the marvel leaped from academic armchairs to popular – and lurid – radio broadcast infotainment, etc.
And the very real Tunguska event … then the long-delayed expedition to the area, and the jaw-dropping National Geographic photographs. Carolina Bays speculation went ballistic.
For a time, in the 1930s and 40s, hardcore science got caught up in it, published positive & supportive articles. By WWII, though, academia had sussed it out sufficiently to know, “Whatever caused these things, it wasn’t a cosmic shotgun blast across the face of America. It wasn’t our mega-Tunguska, and icy comet fragmeting, gouging and then melting without a trace”.
Not everybody got the memo. Some angrily wadding it up and flung it back. Younsters at the time, became seasoned oldsters, in the 1970s and 1980s. They remembered very fondly, and they’d never really let it go.
Yes, Virginia, the Carolina Bays excitement does live on. It happen 12,900 years ago.
The author that I linked to theory is that the bays were formed by impacts of large blocks of ice. That ice was ejected when comet fragments exploded over the Laurentide ice sheet. I suspect the ice blocks would pretty much disintegrate from the various forced places on them as they hurtled through the atmosphere. I could be wrong though.
Oh I think you’re right, and then some.
Yes, I did scan slowly down through Dennis Cox’ big climate page. I saved it; he put a lot of work into it, and it contains various good or interesting things.
Ice-chunk scenarios have a big problem, because ice for sure does lack the mechanical strength for this kind of ‘handling’; it can’t withstand high energy-loading, really of any form or kind. It ‘flows’, just under its own weight, even at 1 measly gee. Any shock-front sufficient to fling chunks 100s of miles, would utterly pulverize them; the powder will then melt, evaporate, and flash to an incandescent ball of glowing steam, all in one bat of the eye. Then the fireball quickly radiates most of the energy into space. Oops.
It would just look an appropriately sized thermonuclear burst, out in the middle of the Laurentide. A disintegrating incoming comet likewise just becomes major fire in the sky. A comet has to be big, in order to get down through the atmosphere, shedding plasma as it descends, but the bulk of it ‘punching through’. Big.
The recent revelation or underscore that even decently-strong solid rock cannot usually withstand atmospheric entry forces for long, puts ice-ideas in an even worse position than they already were. It just goes Boom.
====
There have long been suggestions that Chicxulub can be better-interpreted as a comet; smaller than the energy-equivalent asteroid, but moving very fast (as comets normally do). And it landed in 1,000′ deep continental shelf ocean. If so, then we’re talking about the Muthu of all steam-explosions, followed quickly by the Downpour of All Downpours… a million Niagara Falls ripping out the bedrock over a radius of 100s of miles (mostly just back into oceans) … setting up the Great Grandaddy of All Hurricanes … sucking IN its own ‘dust’-cloud, and water-stripping solids & chemicals back to the surface.
An ice-mediated Carolina Bays or Younger Dryas event suffers the same, much smaller, steam-explosion, radiative-cooling, condensation-catastrophe, self-cleansing dynamic. With significant amounts of ‘over-driven’ ice, we end up with a Beyond Biblical Flood. Forty Days And Forty Nights of torrential downpour, compressed into a matter of hours. And it’s cyclonic, pulling in rather than dispersing the debris-cloud.
The dust & spherules are washed out and carried down watershed flood-ways.
Things do go Bang, but if it starts with ice, it ends up as rain – big rain, fast & hard.
@Richard Dupuis K
January 7, 2015 at 5:57 am
How does one sustain “intense fire and melting” in a mud-brick structure?
Look, I just ask the questions…
The king of Kadesh led a major revolt in Syria around 1500 BC. I suggest you ask some of the troops of Thutmose III….
They had a nice brew-up. A nice cuppa. That’s what soldiers do.
Face the opening windward.
Another scientific theory gone bust. Happens all the time…in real science. But not in climate science, ’cause that just ain’t science.
Are there any outraged persons calling this new theory “asteroid denialism”? Well, there should be. Melted mud bricks, what kind of disaster is that? But no. People think, reflect, evaluate the evidence. What a stange, quiet world compared to the whirligig of climate debate.
There is a lot more evidence of something huge happening back then than scoria droplets. And though it does not support a comet impact, it does support the idea of something celestial and worldwide, given the millions of pictorial representations from all parts of the globe from that era, representations that demonstrate by foreshortening the latitude from which they were observed.
“and coincided with the extinction of mammoths and other great beasts”
Considering that about 50% of species over 70lbs and 100% of species over 2000lbs vanished, I’d say that was an understatement…
Except that that isn´t what happened. Even modern scaled-down bison can weigh a lot more than a ton. And species which disappeared from the North American mainland survived the YD on other continents or islands. Human predation is a better hypothesis to explain the extinctions which did occur around that time.
So does this mean The Younger Dryas was man made?
/sarc