Raymond Effect is a flow effect in ice sheets, occurring at flow divides, which gives rise to disturbances in the stratigraphy, showing unusual arches or anticlines called Raymond Arches.
The Raymond Effect arises from the unusual flow properties of ice, as its viscosity decreases with stress.
Near the base of ice-sheets, stress is proportional to the surface slope, at least when averaged over a suitable horizontal distance.
At the flow divide, the surface slope is zero, and calculations show that the viscosity increases.
[5] This diverts ice flow laterally, and is the cause of the characteristic anticlines, which are in effect draped over the high viscosity area.