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.
papiertigre says:
August 1, 2014 at 12:57 pm
But they still had to count them all.
Bill H. says:
“I rarely visit WUWT now. It used to have some interesting stuff, but this post followed by a message board which unthinkingly dismisses all manner of professional scientists without any justification is cringeworthy.”
“Dr. Easterbrook’s post describes Pingos as low hills that develop gradually over time and then often undergo partial collapse in the centre within which lakes can form. This is completely different from the very large holes that have been noticed within the last couple of weeks.”
WRONG–IT IS THE SAME PROCESS THAT MADE HUNDREDS OF OTHER SIMILAR FEATURES AT YAMAL. YOU NEED TO LOOK MORE CLOSELY AT THE SATELLITE IMAGES.
Yet almost all the posters here demonstrate a child-like trust that the wise Dr. Easterbrook (whose research background, judging from Google Scholar, does not cover geomorphological features such as pingos,
YOUR IGNORANCE IS SHOWING HERE–I SPECIFICALLY DISCUSS PINGOS IN MY THREE GEOMOROPHOLOGY TEXTBOOKS, AVAILABLE AT MOST LIBRARIES..
so he would appear to be speaking as a layperson here) must be correct,
YOU SHOULD GET YOUR FACTS STRAIGHT–IF YOU HAD LOOKED IN MY GEOMORPHOLOGY TEXTBOOKS YOU WOULD HAVE SEEN A PROFESSIONAL DISCUSSION. YOU HAVEN’T DONE YOUR HOMEWORK!
and the experts in such features who are puzzled are dismissed as idiots, or, worse, peddlers of some kind of AGW religion – what evidence do any of you have for this?
WHAT UTTER NONSENSE!! READ WHAT I SAID–NOWHERE DID I DISMISS ANYONE AS AN ‘IDIOT’ OR ‘PEDDLERS OF AGW RELIGION.’ THIS IS AN OUTRIGHT LIE.
Putin’s govt has until very recently been pretty hostile towards AGW theory, so it would be surprising that Russian scientists would feel in any way under obligation to bend the knee before AGW.
TOTALLY IRELEVANT.
Bill H. says:
August 1, 2014 at 1:26 pm
Russian scientists can get funding from foreign sources hoping to promote the criminal conspiracy against humanity of phony Catastrophic Anthropogenic Climate Alarmism. They’re not all totally dependent on the Russian regime, but you’re right that many Russian scientists still practice real science without being corrupted by CACA.
Bill H:
Easterbrook brings very good qualifications to the subject, having interest I’m and having studied for over fifty years geology, glaciology, geomorphology, and climatology. You complain in your comment about unnamed commenters who deprecated unnamed scientists, then sneer at Easterbrook as one who does not know the subject. If any is unqualified it seems to be you. Easterbrook gave a well informed post. Your comment was one long pretentious sneer.
Bill H. doesn’t visit WUWT anymore, but he doesn’t visit it anyless either.
TonyK says:
August 1, 2014 at 3:57 pm
Ok. I don’t know where to go with that.
Can’t wait for a walrus’ are doing X because of global warming story.
Geology is interesting.
http://valleyofgeysers.com
cba says:
August 1, 2014 at 4:53 am
“…evidently, those could be graboid holes….” Heh. So you are one of us derelicts who watched (and enjoyed) the movie “Tremors”.
From the Revkin link
Leibman, the chief scientist at the Earth Cryosphere Institute of the Siberian Branch of the Russian Academy of Sciences, has studied permafrost since 1973 and has a remarkable publication record.
She describes how the first hole (and presumably the new one) appear to have formed as methane is released from a warming mix of ice, water and soil, building up pressure that explosively pushed out the top of the hole, heaving chunks of earth many yards in some directions. She said there were no signs of combustion, that the hole had to be at least a year old because there was fresh greenery from this summer season with no overlying layer of mud or the like.
I’d add that lowering of the water table may have produced a space or porous zone where gas could accumulate. There would be a permafront cap most of the year. As gas pressure increases and the cap thickness decreases in summer, the point is reached when the gas pressure pops the cap. Much like a champagne cork pops.
Last paragraph was my comment.
There is a Pingo National Landmark in the Northwest Territories, designated a landmark in 1984. Doesn’t seem to have holes, but lots of hills pushed up from underneath. Some of them have had small collapses, and now have a lake at the top, with a ridge of rock/dirt at the rim of the lake.
” Janice says:
August 1, 2014 at 8:47 pm
There is a Pingo National Landmark in the Northwest Territories, designated a landmark in 1984. Doesn’t seem to have holes, but lots of hills pushed up from underneath. Some of them have had small collapses, and now have a lake at the top, with a ridge of rock/dirt at the rim of the lake.”
My understanding of pingos is a bit limited, but I thought the general idea was that they don’t become holes until all the ice is gone and the ground collapses into the void left by the melting ice.
Here’s a paper that describes ‘pingo like structures’ under the Beaufort Sea attributed to gas seepage and a mechanism similar to that I describe above.
http://www.ig.utexas.edu/outreach/ice-bound/pepperoni/pdfdocs/pongo%20paul.pdf
Don, thank you for this superb scientific education on pingos, showing the destructive power of water in a freeze-thaw cycle. A great compelling read.
What does Nature use for peer review these days–any competent geologist could have told them how these craters form. Methane in the crater doesn’t mean anything–most all permafrost is full of it.
The journal Nature is full of it.
A lake has appeared in Tunisia. In the desert. People think it is a beach and swimming in it. Worries that it started out blue now green (algae) might have health hazards. Well if it is blue green it will make them very sick and animals too.
Philip Bradley at 8:43 pm
As gas pressure increases and the cap thickness decreases in summer, the point is reached when the gas pressure pops the cap. Much like a champagne cork pops.
Ever seen a champagne bottle with a bad, decaying cork? It leaks slowly with no pop. Even supposing a methane increase, with a summer melting of the cap, there will be ample opportunities for leakage through more than hundred feet circumference of less-than-ideal seal. The heterogeneous makeup of the seal and the unevenness of its melting argue for slow leak rather than a “pop.”
The “crater” in figure 1 has a circular opening thst is much too smooth and regular to have been caused by an explosion. Water expelled by a radially contracting freezing front is a much more compelling explanation from Don Easterbrook. A beautiful display of the power of ice.
But the Hollywood dumbing down of science demands explosions and loud bangs. And of course the lowest most destructive dumbing down is where global warming intrudes its ugly face.
“Looks like the good Doctor may be blind. He claims to have been to Yamal “many times” and yet he has never seen anything like this. I bet he thinks the crater is “unprecedented”
Does anyone really wonder why many of us have such low opinions of many “scientists”?”
It’s like art under the Catholic Church in the 13-16th century, mostly about Jesus and Maria. Or he has one or more pingo’s in his head?
milodonharlani says: “IMO kettles & pingos form in similar ways.”
My understanding is that kettles involve ice above ground and pingos ice below ground. In this case the crucial difference is that kettles would have formed thousands of years ago when the glaciers disappeared and _do not form anymore_ in Yamal, while pingos are still active, still changing the landscape. Apparently, these new crater formations formed quickly. How fast it happened should be investigated, so it can be judged whether regular pingo collapse can explain it.
I’m sceptical towards Don Easterbrook’s approach simply to look at satellite images and conclude that the many ponds formed the same way as these new structures. I think it’s incorrect, since most of these ponds (if they are kettles) do not form anymore.
If the point is simply to say that ice was somehow involved, then it’s likely correct, but everybody already agrees on that, right? The meteorite hypothesis was quickly abandoned. The interesting bit is exactly how ice was involved.
Real scientists are not baffled, only the affirmative action promoted pseudo-scientists racing to get their names in the media.
I do love when a current event makes headlines and draws out the fakes and phonies from their cushy jobs to make clear unambiguous statements identifying them as under-achieving low-IQ frauds. These subjects are irresistible to them, they cannot help themselves. It’s kind of like them wearing a sign on their back that says ‘I am a dumbass’.
Shhh, don’t anyone mention Occam’s Razor to them ( especially that loon women “scientist” who immediately jumped the shark by blaming Global Warming ) because they might accidentally slit their wrists with it.
Stephen Rasey says:
August 1, 2014 at 10:09 pm
Even supposing a methane increase, with a summer melting of the cap, there will be ample opportunities for leakage through more than hundred feet circumference of less-than-ideal seal. The heterogeneous makeup of the seal and the unevenness of its melting argue for slow leak rather than a “pop.”
Permafrost is pretty much a horizontally homogenous gas seal.
Oh good grief. Duster, Bill H., et al of their ilk: are you totally unable to do any research on your own? Journalists want to sell stories. Some ‘scientists’ are clearly scientists only in their own mind.
Here’s a clue for you: go to Google images ans search on “hydrolaccolith”, the scientific term for pingo. There you will see images IDENTICAL to the ‘mysterous’ crators being reported. Then go to any resource, even Wikipedia will do, and search on either word. There you will read, “Recent estimates indicate that more than 11,000 pingos exist on Earth, with more than 6,000 alone in northern Asia.[9]”
There is still some excellent science being done; science I can’t begin to understand. But I am convinced that journalism is dead, and the ones claiming to be journalists seek out the most ignorant or intellectually dishonest scientist to obtain the most outrageous quote for the purpose of creating a story where none exists.
Here’s an example of what you can find: http://www.prairie.illinois.edu/shilts/gallery/shilts-0108.shtml
Kip Hansen (August 1, 2014 at 12:09 pm) “Jimbo gave a couple of quotes, but here are Revkins bits” “She describes how the first hole (and presumably the new one) appear to have formed as methane is released from a warming mix of ice, water and soil, building up pressure that explosively pushed out the top of the hole, heaving chunks of earth many yards in some directions. She said there were no signs of combustion, that the hole had to be at least a year old because there was fresh greenery from this summer season with no overlying layer of mud or the like.”
She’s probably wrong about the methane release. The vertical crack in the permafrost that results in these holes first pushes up dirt around the center. Those “chunks of earth” heaved in many directions are simply frost heaves near the crack. The next step is widening of the crack and collapse of the hole. The last step is a pingo.
Here’s a pictorial description: http://www.fws.gov/refuge/arctic/permcycle.html The only thing that doesn’t match this description is that isolated nature of these holes. In the description the cracks are not isolated, and surrounding cracks would also form holes (not sure about the time scale).
Other possibility of course is a collapsed pingo (picture near the ned of the sequence). But the random chunks of earth are a little harder to fit with that theory, there should be more or less a hill with the hole in the middle.
The last possibility is the mainstream media meme of methane bursts pushing out material echoed by the scientist. Very remote possibility, the main reason being is that methane venting would result in a very choppy ground all around and not a perfectly round hole.
Bill H. (August 1, 2014 at 1:26 pm) “Yet almost all the posters here demonstrate a child-like trust that the wise Dr. Easterbrook (whose research background, judging from Google Scholar, does not cover geomorphological features such as pingos, so he would appear to be speaking as a layperson here) must be correct, and the experts in such features who are puzzled are dismissed as idiots, or, worse, peddlers of some kind of AGW religion ”
Then you need to read further. Several people have pointed out how these are not typical collapsed pingos. If you look into the experts you will not find any consensus that this is some new alarming phenomenon due to methane expulsion. In fact that is only the the result of the media cherry picking the experts and quotes that they like.