Cryosphere > Permafrost

Siberian permafrost hole/blowout

(1/24) > >>

morganism:
They got some samples !

http://www.iflscience.com/environment/scientists-get-first-look-inside-mysterious-siberian-crater

Adam Ash:
See also
http://forum.arctic-sea-ice.net/index.php/topic,484.msg31826.html#msg31826

Jim Hunt:
See also:

http://forum.arctic-sea-ice.net/index.php/topic,416.msg31390.html#msg31390

et seq. They got a new video too:



A-Team:
The Siberian Times has excellent coverage again with another couple dozen photographs. Looking at the vegetation growing in and on the rim mud (no rocks here) --  considering the six week growing season -- it is abundantly clear that the bog huckleberry is not new growth but has been present the whole time.

Thus this was not a high energy event and even moderate heat was never in the picture. Nothing has burned: the darkening of the walls is simply air oxidation of iron and mangenese present in the reduced state in the anaerobic subsurface permafrost, which lines and melts into this drained thermokarst lake. You would see exactly the same thing in any soil pit in waterlogged soil in the US.

You can clearly see extensive drainage channels on the eroded and largely collapsed parapet. This may have just been a 20 m frost heave mound (pingo) with high ice content with surface soil left behind as the ice melted and drained, not even burped-up mud from periodic over-pressurization of melt water.

The volume of mud is not 10% of the volume of the hole. We see meltwater and permafrost icefall at the bottom increasing the size of the cavity. It's not done enlarging yet.

Thus the only thing of interest here is the water table and its drainage. It seems too low for such a soggy landscape. The feature is more or less unique; adjacent thermokarst lakes are not draining at this point. We do not yet know the depth of the water at the bottom.

There may not be drainage at all but simply rather gradual volume loss to volatile gases that escaped upon matrix phase change to liquid. So I expect them to melt a 100 m drill core to see what volume of water, soil and decayed veg is left after the volatile gases have evaporated.

We assume this is primarily methane of biogenic origin but carbon dioxide may also be a significant component. However ethane, propane and butane would indicate natural gas resulting from geochemical processes at great depth.

The name of this peninsula is correctly translated as Land's End. We have dozens of identically named features in the US and one of them houses a well-known mail order store of the same name.

It is a cheap shot to call it End of the Earth with that baggage of sensationalistic, catastrophic implications -- that is utterly missing in the original.

http://siberiantimes.com/science/casestudy/news/first-pictures-from-inside-the-crater-at-the-end-of-the-world/
https://en.wikipedia.org/wiki/Thermokarst

A-Team:
Since the diameter of the feature is ~ 60 m, that would amount to 2x2=4 pixels on 30 m Landsat. Thus a waste of time except for overview of surroundings. Google would have a very much higher resolution image from digiglobe, if they bothered with coverage of this remote site.

However as I explained earlier, the thing to do is retrieve the high resolution image history at Google Earth. (Of course the Russians would be looking at their own 1 m KLH imagery which has been sold for decades.) What I expect to see there is the feature is 1-2 years old. Permafrost melted, possibly forming a visible lake. That melted the frozen ground underneath.

Come winter, the top 1-2 meters froze solid. The liquid water continued to melt its way downward. Gases came out of solution but could not escape due to the ice cap. (Alternatively, a deeper underground gas seep was able to migrate upward through water or softer ice.)

Come spring, the ice cap softened enough that the gas pressure underneath was enough to blow it off, along with a bit of water, ice and top soil. Nothing ignited, this was not an explosion, just taking a warm champagne bottle shaken until the cork flies off.

The most intriguing comment has been from the Russians, saying academic papers from the '80's dated similar nearby thermokarst lakes, all to 8,000 years ago (Holocene warming episode), apparently attributing them to the same mechanism. If so, we may be entering this regime again, though one swallow does not make a summer.

This predicts the walls will continue to collapse for a while as the crater walls are now exposed ice. There being no underground drainage, the crater will widen and fill up with water, ending up looking just like the adjacent lakes.

The whole ridge may be in effect a giant frost heave, predicting that new craters will occur along the ridgeline plateau.

I could not make any sense out of this geologist talking about salt. This is freshwater ice, never mind if it has been submerged at some point. There is nothing in there that could ignite methane or peat, certainly not nitrate or sulfate. Methane cannot oxidize without something else being reduced.


Navigation

[0] Message Index

[#] Next page

Go to full version