Physical Characteristics of Near-Shore Ice Ridges

Investigations of the morphology and composition of near-shore ice ridges were conducted on the southern shore of Lake Superior near Grand Marais, Michigan, and at other Great Lakes locations during 1970 and 1971. Data are given for ice densities, sediment load, temperature and internal arrangements of ice forms. A cross-sectional map of the gross structure of one ice ridge is also presented. The basic internal appearance of the ridges is similar to that of conglomerate rock, and little stratification occurs. These ridges are seldom discussed in the literature but commonly appear along the shorelines of the Great Lakes. It is suggested that they are developed primarily as a product of wind and spray processes and are not to be confused with pressure ridge and ice thrust features.