Contemporary Formation of Patterned Ground by Soils in South Dakota
Soils with surface patterns (gilgai) from South Dakota and other parts of the world have been described in the soils literature. Patterns of sloping, wavy gilgai and nearly level, normal gilgai seem to be analogous to stripes and nets, described as frozen-ground patterns in the geologic literature. Gilgai patterns in South Dakota, however, display soil profiles which show that the pattern is not relict but is forming today. It is important that the patterned soils of a site be described accurately, and that the age of the site, its moisture regime, and soil texture be likewise determined before one may conclude whether the pattern is relict or is actively being formed. In order to help differentiate patterned ground that is actively forming in warm climates from that either forming or already formed in cold climates, we propose that the gilgai nomenclature of Hallsworth and others (1955) be used for the former, and that of Wash-burn (1956) for the latter.