Guest essay by Don Easterbrook
A crater in northern Siberia, spotted by a passing helicopter, has received worldwide attention and continues to be a top news story. Since then, two more mysterious holes have been discovered elsewhere in the region. Now the new holes, smaller in diameter but similar in shape – are posing a fresh challenge for Russian scientists, according to the The Siberian Times. Theories range from meteorites to an explosion of methane due to global warming.
Figure 1. Yamal ‘mystery crater.’ (Siberian Times)
Anna Kurchatova of the Sub-Arctic Scientific Research Centre said the crater was formed by a mixture of water, salt, and gas igniting an underground explosion as result of global warming. Kurchatova suggests that global warming may have caused an ‘alarming’ melt in the under-soil ice and released gas, causing an effect like the popping of a champagne bottle cork. ‘The version about melting permafrost due to climate change, causing a release of methane gas, which then forces an eruption is the current favorite, though scientists are reluctant to offer a firm conclusion without more study.’
Scientists with the Russian Academy of Sciences Institute of the Earth Cryosphere, which is leading the investigation, suggested that the holes formed when melting permafrost triggered an explosion of methane gas. That theory was bolstered when an icy lake was found at the bottom of the hole. Andrei Plekhanov from Scientific Research Center of the Arctic said the crater appears to be made up of 80 percent ice, which adds to the theory that it was caused by the effects of global warming.
Dr. Plekhanov said: “I’ve never seen anything like this, even though I have been to Yamal many times.”
WHAT IS REALLY GOING ON HERE?
Actually, these craters are not mysterious at all—there are hundreds of them all over the Yamal Peninsula and their origin has been well known for many years.
Figure 2. Craters of the Yamal Peninsula. The ice cores have completely melted out, leaving lakes. The surrounding ridges are still visible. (Google Earth)
As you can see from the images in Figure 2, there are hundreds of these craters, mostly not as fresh as the recent ones, but showing the same features—a depression surrounded by a ring of raised ground. These are pingos!!
Pingo is an Inuit term for an isolated, dome shaped hill, used to describe large ice-cored mounds found in the permafrost regions of Siberia and various other places in the Arctic. Pingos range in height from a few meters to more than 40 m (130 ft) and from a few meters to 1,000 m (3,300 ft) in diameter. Small pingos typically have rounded tops, but larger ones are commonly broken open at the top where melting of the ice core forms a crater resembling a volcanic cone Where they occur in stratified silt or sand, the beds commonly dip outward from the center, much like those adjacent to an intrusive body. The ice in the core of a pingo is typically massive and of segregation/injection origin. Tension fractures are common at the summit of the mound, but expansion of pingo ice is rare and short-lived. Ice up to 7 m (23 ft) thick has been found in pingos of Sweden. As the ice core melts, a small freshwater lake may occupy the summit crater that forms.
Open system pingos
Open system pingos form where groundwater under artesian pressure beneath thin permafrost forces its way upward and freezes as it approaches the surface where it forms an ice core that heaves the surface upward. Although the initial growth of these types of pingos may occur where ice lenses lie above the water table, their continued growth requires a particular combination of hydrostatic pressure and soil permeability. Thin, discontinuous permafrost and artesian water pressure play important roles in the development of open system pingos. The role of artesian pressure is not to force the overlying sediments upwards but rather to provide a slow, regular supply of groundwater to the growing ice core.
Most open-system pingos are oval or oblong in shape and typically occur as isolated mounds or in small groups developed in either soil or bedrock. Rupturing near their top is common. Concentrations of open-system pingos occur in Siberia, the northern interior of the Yukon, Alaska, Spitsbergen, and Norway.
Closed system pingos
When a lake in a permafrost environment is progressively drained and covered by encroachment of vegetation from the margins, the permafrost table progressively rises to the level of the former lake floor. The rising permafrost table expels pore water ahead of the freezing front, and when the pore water pressure exceeds the overburden strength, upward heaving of the frozen ground occurs as the ice core progressively grows. The size and shape of the resulting pingo typically reflects that of the original body of water.
Closed system pingos vary in height from a few meters to over 60 m (~200 ft) and up to 300 m (~1000 ft) in diameter, ranging from symmetrical conical domes to asymmetric and elongate hills. The top of the pingos are commonly ruptured to form small, star like craters that eventually form shallow-rimmed depressions as the ice core melts.
The mechanism of pingo formation in a closed system starts with a deep, ice-covered lake, surrounded by permafrost. The lake inhibits the development of permafrost beneath it, and the ground remains unfrozen. As the lake is slowly drains or is filled with sediment, at some point the lake ice freezes to the bottom, and the bottom sediments begin to freeze. As the layer of ice and permafrost covers former lake floor, a closed system is set up in the still-unfrozen ground beneath because the permafrost cap prevents the escape of groundwater. As permafrost continues inward growth around the unfrozen core, water pressure increases. Pore water is expelled from the unfrozen sediment by the advancing permafrost, and to relieve the pressure, the surface bulges upward. Eventually, all of the water in the enclosed system groundwater mass becomes frozen and the excess water forms a core of clear ice under the bulge.
Growth rate of pingos:
The birth and growth of a small pingo studied by Mackay (1988) is representative of more than 2,000 closed system pingos of the western Canadian Arctic and Alaska. The pingo appeared on the former floor of a lake that drained suddenly about 1900. Small frost mounds began appearing between 1920 and 1930. The pingo grew steadily until 1976, but the growth rate decreased after that. Mackay also monitored the growth of other small pingos in a lake in the Mackenzie Delta region that drained between 1935 and 1950. The pingos grew rapidly in the initial years, commonly 1.5 m/year (5 ft/yr), then decreased. Mackay suggests that about 15 new pingos per century appear in the Mackenzie Delta region, and only about 50 seem to be actively growing. Similar conclusions have been reached by Russian investigators in Siberia.
Duster (August 1, 2014 at 9:39 am) “So, here’s a thought. Could there be masses of methane ice or more likely clathrates under Yamal that also cause pingo formation?”
Here’s your challenge: explain why the hole is perfectly round. Sinkholes can be perfectly round from circular surface formations or conical subsurface formations. The problem with the methane theory is that there is no evidence of tubes of methane or anything like that.
Here is a nice example of a pingo hill (described as a frost-heave) in Yamal that has not collapsed yet. Not quite as big as the example we are talking about but perhaps half.
http://www.netpilot.ca/geocryology/Photo%20Gallery/photos/Frost%20heave%20on%20Yamal%202.jpg
Another in Yakutia to the east. Same size as the current example but this is in a semi-treed area versus Yamal which only had trees in the MWP and the Holocene.
http://www.netpilot.ca/geocryology/Photo%20Gallery/photos/Frost%20heave%20in%20Yakutia%202.jpg
Many pics from a “geocryology” focussed website of permafrost features.
http://www.netpilot.ca/geocryology/Photo%20Gallery/default.htm
A pingo ate my baby!
Jim Clarke says:
August 1, 2014 at 7:21 am
…..
I very much appreciate Don Easterbrook’s article on pingos, and agree that it is the best explanation so far, but I still have some questions, mainly because this Yamal hole is so deep! Are pingo lakes typically this deep?
===========================
I agree on all counts Jim. A quick check of Wikipedia the other day convinced me that pingos are real enough — although I’ve never seen one or the remains of one. And I’m willing to believe that the first hole to make the news is a pingo although, I like you am bothered by the depth of the hole. Not that I disbelieve that it’s a pingo. It’s just that I can’t quite envision how it evolved to its current state. If it’s a result of melting, there must be some sort of (deep?) drain?
The other minor point is that the locals near the second two holes seem to have reported that they appeared overnight and there were explosion sounds. The “explosive” origin could be imagination or confusion with some other phenomenon — thunder perhaps? We all know how unreliable “eyewitnesses” are. But still, if there was/were explosion(s) it’d be nice to have an explanation of how they came about.
@Philip Bradley at 3:03 am
Permafrost is pretty much a horizontally homogenous gas seal.
But we are not talking about permafrost, are we?
We are talking about permafrost, punctured by artesian spring frozen by polar winter into sod covered ice plugs, then differentially melting during the summer.
“Pretty much” I agree with. My point was that the places where these pingo are forming (and melting) are the exception and the point of weakness. For a pop, the entire ice plug must go at once with no premature leakage around the perimeter and for an irregularly shaped ice plug, that’s asking a lot..
But here is a thought to mull: Could a methane gas cap be a pressure driver of the artesian system? When the methane leaks, up dip from the pingo, the water table at the pingo drops quickly. Personally, I rate this as a low probability — I think downdip changes to the artesian system are the better bet.
Here is some exposed permafrost at Tuktoyaktuk with pingos in the background. These are definitely not a new phenomenon.
http://www.cbc.ca/news/canada/north/thawing-permafrost-sinks-buildings-hikes-costs-in-north-1.1108686
It seems that climate scientists and journalists are gradually ‘discovering’ geological phenomena one at a time and the hyperbole continues. I wish they would take a geology course and calm down. The ignorant belief in sea rise to submerge atolls and deltas is a favourite, but it is well known to geologists for over a century that both these features rise with the sealevel. I studied it in the 1950s. Hansen’s discovery that there had been a half a degree of warming since late 19th Century, coupled with his astronomical studies of planet Venus led him to the alarm that we where headed for Venus’s fate is another example. The temperature swings of the earth over geological history soon came to his and colleagues notice from geologists and instead of putting an end to the matter, they had to make a two decade warming of 0.5C (with a little help from putting his thumb on the scale), as being different, unprecedented. A pause and cooling that is now longer than the ‘unprecedented’ warming has forced some understanding of natural variability upon them. Gee whiz, they could have had all this and more with Geology 101, 201… in a year or two at school. I’ve mentioned before that a PhD sociological study (that will never be done) could determine the percentage of the population that are thinkers (real skeptics, not simple contrarians) and the overwhelming proportion of those who are uncritical accepters of whatever is put in front of them.
Some science snuck in to the Scientific American article about the holes:
“This part of Siberia contains deep gas fields, and it also contains a lot of small lakes, which formed between 4,000 and 10,000 years ago when the climate was warmer”
Alas Slate was not concerned with science:
“It’s as if the Earth is celebrating. Soon, no more humans!”
Steinar Midtskogen says:
August 2, 2014 at 12:47 am
Kettles may form from exposed ice blocks stuck in the ground, but IMO typically are covered with some windblown or otherwise deposited sediment before melting. But in any case they do as you observe melt sooner than the blocks buried in tall, conical hills, ie pingos.
Stephen Rasey says:
August 2, 2014 at 8:42 am
But we are not talking about permafrost, are we?
We are talking about permafrost, punctured by artesian spring frozen by polar winter into sod covered ice plugs, then differentially melting during the summer.
You seem to be assuming some role for the conventional pingo forming mechanism.
I am not.
I think they merely look something like pingos.
See my reference to ‘pingo like structures’ above. Especially, the older biological material lying on top of newer material around the edges of these structures. That for me is conclusive of the structures being formed by extrusive pressure from below. Quite unlike the pingo forming mechanism.
I’d also note that despite the dramatic pictures, these features are small. The original one was only 100 ft across. The 2 more recently discovered, only 44 and 13 feet across.
I suspect this is a fairly common phenomena, gone un-noticed to date.
regards
So to sum it all up:
1) Some new craters were discovered in one of the most remote places on earth
2) Despite having an well known and documented cause the news media jumped on the global warming bandwagon (Why not meteors, well astronomers would be quick to debunk that and hey global warming causes everything right)
3) The responsible scientist come forward and say it’s not global warming
Now there are two ways I see this going forward.
1) Just forget that global warming was ever mentioned and continue to study this as a unique instance of a well known natural occurrence
2) Keep claiming it’s global warming long after rational scientist have discarded that theory
Now which do you think is more likely.
Remember the film “Chronicle”? If you climb inside one of these things maybe you would come out posessing telekinetic powers.
An old classmate of mine, Gary Wingo*
had a sub that he kept in a pingo.
It was yellow and clean
a most righteous machine
but one day he could not make the thingo.
So he sent for an expert named Ringo
who claimed he could fix it, by jingo
“I’ll just replace the gaskets
with the ones in this basket
made of leather I tanned from a dingo.”
* Real fellow
Isn’t there a female politician / scientist named Slingo?
Yamal is suffering from PMS, ie Pingo-Mimicking Structures.
Congratulations to Bill H for pulling off a standard internet troll meme. The “I don’t come here much anymore, but back in the mythical Golden Age I’m pretending to remember, everyone was ever so much smarter and didn’t post things I don’t like. So you are poopy heads.” Pretty funny and it’s a classic.
I’ve been hanging around here pretty much since day one and the discourse is at as a high a level as ever. I’m generally pretty knowledgable about many of the topcs discussed here, but I learn something nearly every visit.
@Philip Bradley at 11:22 am
[to Stephen Rasey]
You seem to be assuming some role for the conventional pingo forming mechanism.
Indeed I am. Occam’s Razor: It states that among competing hypotheses, the one with the fewest assumptions should be selected. Other, more complicated solutions may ultimately prove correct, but—in the absence of certainty—the fewer assumptions that are made, the better. [Wikipedia]
I am content to call these Open System Pingos [Wikipedia] that have met an unusual demise — the relatively sudden drop in the water table.
An Open System Pengo is an artesian spring that freezes solid in the polar winter like the permafrost around it. But hydrostatic pressures of the artesian system exert pressure from below to lift the ice plug. The Pingo core is less dense than the permafrost around it, so the Pingo ice is buoyant, much like a salt diaper and grows vertically. They have an old cap with new material scraped from the permafrost sides of the core transported up to the surface at the edges of the pingo and deposited with the melt water during the summer. Think of them as a vertical glacier, with hydrostatic forces moving the glacier up, depositing its moraines circumferentially on the surface around the ice core.
What is different about these holes from normal pingo structures? They are holes, of course. What is important is that they are not holes filled to the surface with water. The water table in the vicinity of these holes is 40 to 80 meters below the surface. Either:
1. these never were artesian systems, the water table has always been low, and therefore they are not Open System Pingos, which I guess is something like your hypothesis, or
2. They WERE Open System Pingos, but something made the water table drop quickly, killing off the Pingos we know about — and probably many others soon to reveal themselves.
Do I know what caused the water table to drop? But I have three theories:
1. a methane gas cap in the aquifer under the permafrost was maintaining artesian level hydrostatic head. Something caused the methane gas cap to depressurize, and the hydrostatic head dropped quickly. I view this as very unlikely.
2. other Pingos that are part of the same artesian aquifer that are down slope from these mysterious holes have melted this year more than usual and are gushing water, lowering the water table for Pingos upslope. This is quite possible, but there will be an obvious surface change in water flow compared to previous years. It is testable.
3. Gazprom has been developing for the past 8 years a super-giant gas field, Bovanenkovo (over 170 TCF, that’s 170,000 BCF, in place) roughly 30 km away from these mysteries; these dead pingos. There may be other developments near by, too. From where is the Yamal Project getting its fresh water for drilling fluids, formation stimulation and operations? Where can they get a year-round water supply? Could it be the aquifers that fed these now-dead Pingos? This, too, is a testable hypothesis… If we could get the data from Gazprom. This is the hypothesis I find most likely.
Stephen Rasey says:
August 2, 2014 at 5:42 pm
Excellent dot-connection on your part, based upon solid information.
Explosion or Implosion? — “Pop” or “Plop?”
As written above, I am a supporter that these mysterious Yamal holes are “Open System Pingos” that have met their demise by a relatively rapid drop in the hydrostatic head of the artesian system that gave birth to the pingos.
Given that hypothesis, how can I explain the “explosions”?
What I think they heard was not the “Pop” of “a mixture of water, salt, and gas igniting an underground” [ Really, Ms Kurchatova ?? ]
but the “Plop” and “Whump” of a multi-kiloton partially melted pingo Ice core and cap rock, giving way and plunging 20-50 meters to the bottom of the pingo shaft. I bet it even shakes the ground when it hits bottom.
It was an Implosion, not an explosion. It fell in on itself.
There is no need for an underground methane explosion. (Where is the source of oxygen? If water, salt, and methane was a common explosive mixture, we would not have a Natural Gas Industry.) Gravity plus a big, partially melted pingo core and its caprock, hanging above a now airfilled, or methane filled, chamber where the artesian waters once filled, is all the potential energy you need for a big, reportable, “Thud”.
Presto. Next morning, there is a new hole formed, someone who reported a sudden noise like an explosion, the ground might have even shook. No explosive evidence scattered on the country-side. No burn marks. A nice clean hole, with a counter-sunk rim. With ice and (melt) water at the bottom.
Dr. Easterbrook. Please learn how to properly quote and respond. Using all caps is considered very bad form.
A reasonable and cheap test of the Implosion theory.
The Implosion, “Plop” theory argues that the pingo cap soils and plants went straight down and is under the water at the bottom of the hole.
Drop an ocean-bottom or lake-bottom coring tube into the bottom of these mysterious holes. Do you find the core’s contents include tundra, pingo-cap soils and plants? .
If yes, then how did they get there if it was an explosive event?
If no, then Implosion looks less likely.
Stephen Rasey says:
August 2, 2014 at 6:25 pm
Explosion or Implosion? — “Pop” or “Plop?”
What you don’t explain is the material up to 1 meter deep deposited around the edge of the hole.
I can’t see how this could occur without a ‘pop’ (or an impact, which we both discount). Of course, once the initial pop has occured, there will be a ‘plop’ as the material not falling outside the hole, falls back in, especially if there was a gas filled cavity.
I am not suggesting combustion. Movement of substantial amounts of material, up, down or both would produce noise, which would sound like distant explosions.
It seems no one has sampled the material deposited around the hole. If it contains older biological material, this would be conclusive of a ‘pop’.
Also from wikipedia.
Aristotle writes in his Posterior Analytics, “we may assume the superiority ceteris paribus [all things being equal] of the demonstration which derives from fewer postulates or hypotheses.”
You can’t disregard the evidence of material deposited around the hole, because it doesn’t fit your theory.
* If my theory is correct, I’d expect to see the hole at the center of a somewhat raised dome, as described in the ‘pingo like features’ paper above. I can’t tell from the photographs whether the surrounding land is raised or not.
Some good photographs and quotes from scientists here. Gives a good idea of the amount of ejected material, substantial but clearly not enough to form the hole.
http://siberiantimes.com/science/casestudy/news/first-pictures-from-inside-the-crater-at-the-end-of-the-world/
Where are the geologists amongst us? Personally it looks like a sink hole from an old volcanic tuf.
What about the lake that has just appeared in the Tunisian desert. Blue to start with now green algae, that could be a health hazard if it is blue green algae to the bathing people and any animals that drink the water. At least the hole is not near any human settlement.
@Philip Bradley at 7:10 pm
[To Stephen Rasey]
What you don’t explain is the material up to 1 meter deep deposited around the edge of the hole.
I do explain it.
You and I differ on WHEN the “material up to 1 meter deep” was deposited. I think it was deposited many decades ago as the pingo grew. When it collapsed, the cap and attach sod on the flanks of the dome fell into the hole. I gather you think most of that rim was deposited during the pop, but I think there is too much and too localized to have happened overnight.
I’ll modify my Implosion theory slightly. More like extending it. When the ice core, cap and sod fall into a gas (air, methane, whatever) filled cavity (that once held the artesian water, now removed), the gas will have to escape. There will be a “jet” of that gas out of the hole as the core falls into it. A burp. That jet could expel a minor amount of material. Not the ring moraine piled up on the edge but the odd dirt clod.
It seems no one has sampled the material deposited around the hole. If it contains older biological material, this would be conclusive of a ‘pop’.
Older than what?
It is difficult to believe no one has sampled the material from the raised ring (circular moraine) around the hole. We may not know what they found. But I expect the ring moraine to be quite old because it was deposited during the growth of the pingo, not overnight in either a pop or plop. If someone cross sections that moraine I don’t think they will find tundra buried less than 2 years — unless there was slumping of the pingo flanks as the core collapsed in the implosion.
Stephen Rasey says:
August 2, 2014 at 11:10 pm
You and I differ on WHEN the “material up to 1 meter deep” was deposited. I think it was deposited many decades ago as the pingo grew. When it collapsed, the cap and attach sod on the flanks of the dome fell into the hole. I gather you think most of that rim was deposited during the pop, but I think there is too much and too localized to have happened overnight.
Indeed we do.
In the photographs in my most recent link above, the bulk of the IMO extruded material looks ‘fresh’ with minimal vegetative growth indicating a recent event.
In addition, the permafrost here is at least 100 meters thick and probably more like 300 meters thick. This would make it structurally stable and I have trouble seeing gravity alone having the force to collapse it in such a small area. And note the more recently discovered smaller holes. I’d say it would be impossible to collapse these by gravity alone due to the permafrost thickness.
Were this a pingo moraine as you propose, I’d expect to see signs of erosion, which I don’t. But erosion over decades wouldn’t be too obvious on photographs I’ve seen.
Thanks for the interesting discussion. I think the Russian scientists will likely resolve this for us in not too long.
@Philip Bradley at 12:48 am
In the photographs in my most recent link above, the bulk of the IMO extruded material looks ‘fresh’ with minimal vegetative growth indicating a recent event.
I agree with all this. As well as the thick stable permafrost
But I can achieve it with a normal pingo, who’s supportive artesian system has been hydrostatically killed, probably by Gazprom needs for fresh water. This spring, the decades old existing pingo ice core with a bulbous top that was supported by the artesian system found itself hanging many meters above the now lowered artesian water table. As the summer warmed, the ice core melted to the point where catastrophically failed and fell into the gap. It imploded. As it fell, the tundra cap of the pingo and its connected sod on the flanks of the pingo fell into the hole. There is also a “burp” of gas displaced by the falling ice and sod. What is left is naked circumferential moraine (deposited decades ago) on the edges of what looks like a countersunk hole.
It was a Plop. And it tore the tundra off the sides of the pingo as it fell.