Do these things have a name?

[colospgs]

I've seen these "rivers" of black rock, mainly in the Mosquito range, but also in other places. Is there a name for these or should I just keep calling them "rivers of black rock"?

IMG_2398 small size.jpg

[timewarp01]

The geologic term for areas like this is 'patterned ground.' In regions with permafrost or seasonally frozen soil layers, rocks can be selectively sorted out of dirt over long periods of time due to frost heave, which is a lateral pressure that arises when soil expands when it freezes, sometimes up to 110% of its unfrozen volume. The expansion pushes rocks upward and outward, but when it thaws the soil tends to ooze and flow back down through the cracks and gaps in the rock piles. The result is that buried stones tend to rise to the surface, and surface stones tend to accumulate into clumps. On level terrain this forms roughly circular pockets of bare stones alternating with pockets of soil and tundra. On angled terrain, the pockets of rock are elongated by gravity into the long stripes in your picture.

[colospgs]

Thanks Timewarp,

That's an excellent description. I read more about that online. Happier now that I know more about it. Although I still think it needs a better name. Maybe I'll stick with black rock river or something.