Patterned frozen soils get their shape from gravity and funky physics

Hillslopes in Arctic regions with frozen soils can host a suite of geometric patterns, from circles and stripes to polygonal patterned ground.

They can also have solifluction patterns, or markings left behind when partially thawed permafrost slips and flows down a slope.

Solifluction patterns look like pairings of flat, terraced soil—like a big staircase—and rounded lobes of soil at the terrace's base. ...