Tuesday, July 22, 2014

that hole in Siberia: Pingos and periglacial geomorphology

80m hole in Siberia
Lots of excitement has been seen online surrounding the appearance of this hole in Siberia on 15 July 2014.

~Was it a meteorite? An explosion from underground due to secret Russian experiments? The rupture of a tunnel leading to the inside of our Hollow Earth? UFOs?~

Most likely, this was the eruption of an unusually large "pingo."

Pingos (aka hyrdolaccoliths or cryolaccoliths) are formed in periglacial regions where permafrost exists and can be thought of as a slow, cold geyser not unlike Old Faithful in Yellowstone. Instead of geothermal processes, pingos
image from the British Society for Geomorphology
form through frost heaving upward through glacial till and other materials to form bubbles on the surface which look like hills. When they rupture, the ice that was at its core is revealed and sometimes a small lake even forms.

The crater in Siberia matches this criteria perfectly: there is even a lake of ice water at the bottom of the shaft under the crater that is about 230 meters deep. This is consistent with the definition of a pingo.

Closed-system pingos are ones that have not yet ruptured and appear as a mound or hill on the surface. Open-system pingos are ones that appear as craters or lakes inside of craters. The Siberian hole seems to be an extremely large pingo 80 meters across that did not form a lake but opened to reveal the cylinder hollowed out by groundwater and the lake of ice water at the bottom.

It's an unusual and strange landform to those of us in more equitorial climes but they are fairly well-known in northern latitudes and far more interesting than those explanations listed above.

Want to know more?
--Online sources--
Tuktoyaktuk Pingos (Atlas Obscura): http://www.atlasobscura.com/places/tuktoyaktuk

Periglacial geomorphology, Geography 323 (University of Regina): http://uregina.ca/~sauchyn/geog323/periglacial.html

Periglacial geomorphology (PDF) (University of Victoria): http://www.geog.uvic.ca/geog276/2013/276_lecture08_2013_periglacial.pdf

Periglacial processes and landforms (PhysicalGeography.net): http://www.physicalgeography.net/fundamentals/10ag.html

Siberia's giant hole just became less mysterious (Nature World News): http://www.natureworldnews.com/articles/8147/20140719/siberias-giant-hole-became-lot-less-mysterious-video.htm

--Books at Ball State Libraries--
Cryospheric systems : glaciers and permafrost GB581 .C79 2005 (GEN-COLL)

Glacial and periglacial geomorphology GB581 .E452 1975 V.1-2 (GEN-COLL)
Glacial geomorphology : [proceedings] GB581 .G46 1974 (GEN-COLL)   

Glacial landsystems GB581 .G533 2003 (GEN-COLL)   

Glacial processes past and present GB2401.2 .G53 1999 (GEN-COLL)   

Living ice : understanding glaciers and glaciation GB2403.2 .S5 1988 (GEN-COLL)   

The periglacial environment GB461 .F73 (GEN-COLL)

The periglacial environment: Past and present GB641 .P37 (GEN-COLL)

Surface processes and landforms GB401.5 .E26 1999 (GEN-COLL)