The UAF-CRREL Permafrost Tunnel, Fox Alaska
Fox Permafrost tunnel is run by UAF and the Army corps of engineers'
Regions Research Labs. Permafrost and frozen ground seriously
complicate construction of roads, buildings etc., as evidenced by the
fact that the parking lot behind the Geophysical Institute often
collapses. Hence UAF's and A.C.E.'s interest in studying it. Here are some surface manifestations of
Permafrost, and melting there-of.
Not far inside the tunnel, a
femur sticks out of the wall. The scaffolding lining parts of the
tunnel is not confidence-inspiring; nor are the dead bones sticking out
of the walls.....
even bigger, ice-age bone, tree root and tundra-plant roots. These are
some 20-30 feet below the surface, and date back 15-20 thousand years.
All this ground is frozen; it would be a sloppy mess if it melted.
ancient tree roots; these are tundra willow roots, which are more like
tough bushes than trees. These are the same kind of bushes that have
Alaska'a north slope due to Arctic climate warming (a term which
makes Alaska's congressional reps spontaneously 'bury their heads in
The roots of an ancient tundra layer hanging from the ceiling. All of
this organic matter is preserved being frozen in permafrost. If the
ground thaws, all this stuff would decay, releasing huge amounts of
methane and carbon dioxide, both strong greenhouse gasses.
River rocks and gravel (left) and 'loess' (wind-carried glacial dust),
side-by-side in the wall of the tunnel. The gravel fills what once was
the bed of a stream that flowed through the loess.
Here an 'ice
wedge' cuts across the tunnel. These things can extend
tens-of-meters into the ground, and all the way up to the surface,
where they typically underlie one form of arctic 'patterned ground'.
Patterned ground also occurs
on Mars! Though we are not positive that it arises the same way
as on Earth, the Mars Phoenix lander apparently landed
on this kind of terrain.
Here's a picture of it in the tunnel's ceiling. All those fine
striations in the ice are places where the ice cracked open, when the
surrounding permafrost contracted in the cold of winter. Water fills
the cracks in spring, and re-freezes. This is how ice wedges grow.
An ice lens in the wall. This is a branch of an ice wedge that has
spread horizontally from the main wedge.