A highly mobile Laurentide ice sheet revealed by satellite images of glacial lineations

Satellite images of the North American continent are discussed which reveal previously unrecognized patterns of crossing drift lineations which aerial photography and ground surveys reveal to be sediment ridges oriented parallel to former glacial flow. The lineations reflect unexpected shifts of centers of mass of the Laurentide ice sheet throughout the last glacial cycle. The relative chronology of the lineations is examined and correlated with stratigraphy and dating, and the development of the ice sheet is followed through the glacial cycle.