Abstract
Adhesion structures form by the adhering of dry, wind-blown sand to a wet or damp surface. In plan-view morphology and internal structure (in parentheses), three adhesion structures occur: adhesion ripples (climbing-adhesion-ripple structures), adhesion warts (adhesion-wart structures), and adhesion plane bed (adhesion laminations). Related features are evaporitic-adhesion structures formed with surface salt growth. Experimental growth shows that these types result from subtly different environmental factors; this enhances the value of adhesion structures as tools for paleoenvironmental interpretations. Factors involved are water content, wind direction variability, depositional surface condition, and the impact angle of saltating grains. The Cambrian Galesville Sandstone, Wisconsin, shows an abundance of adhesion structures; this allows for the recognition of repetitive sequences from the lateral migration of eolian dunes, interdune areas, and marine environments. Adhesion structures also occur in the Ordovician St. Peter Sandstone, Wisconsin, indicating that parts of this formation was deposited subaerially.--Modified journal abstract.
