... Fred the Periglaciologist! Living where he does, his is a profession of choice.
Periglacial sand wedge, southeast Wyoming.
The source of the spectacularly-colored fill
Fred is in his eureka pose, having just come across a spectacular exposure of sand wedges in a ditch in the west part of town. “Sand wedge” is a misnomer; fill material is not restricted to sand -- it can be finer or coarser. The name is used to differentiate these wedges from ice wedges, which form in wet environments. These that Fred found are relics of cold dry Pleistocene times when there was permafrost in the Wyoming basins. Thermal-contraction cracks filled up with whatever blew in -- loess, sand, miscellaneous debris.