Most commonly in periglacial areas, the arrangement of stones into polygons, isolated circles, and concentrations of circles known as nets, steps, and stripes. Polygons and circles are more common on level surfaces, stripes generally form on slopes; the patterns are made of coarser stones, separated by much smaller stones (fines).
George et al. (1989) Geophys. & Astrophys. Fluid Dynam. 46, 3 argue that convection currents within the active layer produce patterned ground; Grab (1997) ESPL22 cites desiccation and the formation of needle ice as major causal processes. Matsuoka (2003) Geomorph. 52, 1–2 attributes patterned ground to the upward injection of slow-freezing, waterlogged silts at particular points. Kessler and Werner (2003) Science 299, 5605 note self-organization in patterned ground.
Subjects: Earth Sciences and Geography — Ecology and Conservation.