Cold landscapes carry patterned ground, where stones gather into stripes and polygons with soil between them, and no hand placed them. is increasingly recognized as fundamental to pattern formation in geomorphology. Relative to other fields, the underlying mechanisms have received little attention from theoreticians.
Ice needles, acting as a . Growing ice segregates soil from stones, through feedbacks between how concentrated the stones are and how the ice forms around them. Measurements of stone concentration and of displacement show that phase separation theory accounts for both the sorting and the patterns it leaves behind.
Self-organization is increasingly recognized as fundamental to pattern formation in geomorphology. Relative to other fields, however, the underlying mechanisms have received little attention from theoreticians, which leaves a well-known landscape feature without a quantitative account.
The authors introduce phase separation theory to study the formation of patterned ground in cold regions. Sorted here refers to the segregation of soil and stones due to feedbacks between stone concentration and recurring .
The test is empirical rather than purely formal. Using detailed measurements of the concentration of stones in soil and of their displacements, the authors show that phase separation accounts for the observed sorting and for the patterns themselves.
The framing has a use beyond the explanation. The study highlights phase separation theory as a source of insight into ground patterns in cold regions, and points to their potential value in signaling important changes in ground conditions with the warming climate.
wat. Each freeze lifts the soil a little and leaves the stones behind.
wat wat
These patterns may flag important changes in ground conditions as the climate warms, and that is why it is worth learning to read them.
How do we know?
Li and colleagues brought phase separation theory to patterned ground, then tested it with detailed field measurements of how concentrated the stones were and how far they moved.
What is still unknown
A theory matched to measurements in cold-region soils rather than reproduced from scratch in a laboratory.
Learn something?
Where to next
Who punches an almost perfect circle through a layer of cloud?ice
How does a round disk of ice start turning on still water?ice
What decides how thick a field of pancake ice ends up?freezing