Stone Orientation in Wadena Drumlin Field, Minnesota

Stone-orientation analyses in till of the Wadena drumlin field in west-central Minnesota show that long axes of elongated stones are statistically oriented parallel to the long axes of the drumlins, and that the plunge of the long axes (inclination downward from the horizontal) is preferentially in the direction from which the ice came, at gentle to moderate angles (average about 23°). It is suggested that the up-glacier plunge of the elongated stones may be the result of movement of basal ice on planes of flow inclined up-glacier at gentle to moderate angles.The Wadena drumlins consist of till deposited by basal ice, but the localization of the drumlins is not explained. The hypothesis that drumlins may be formed by squeezing of till into basal crevasses is not supported by evidence from the Wadena field.