Roche moutonnée

A round bump ( French Roches moutonnées ) is too streamlined bodies reshaped by glaciers bedrock. On the windward side of a rocky obstacle the pressure of the ice leads to basal melting and thus to the formation of a lubricating film between glacier and rock. Here, the surfactant immersion produces a smooth, streamlined surface with glacier scrapes. On the leeward side freezes when the pressure laid the rock on the glacier base, whereby individual blocks can be demolished to divide land ( Detraktion ). Furthermore, it is on the leeward side occasionally to frost shattering. These processes lead to a harsh, often step-like surface finish of the leeward side of a round hump. As a rule, round bumps in groups. As an individual forms they occur rarely. In addition to the occurrence at high altitudes they exist also on the coast, as in Finland or Nova Scotia ( Canada).