An enormous amount of load is transported by the moving ice. When the ice begins to melt and the glacier slows down, the load carried by it gets deposited. All the rock materials tend to accumulate at the terminus of the ice-sheet.
As in the case of valley glaciers the deposits formed by the ice-sheets are also of two types, such as – Unstratifed deposits (till) and Stratified deposits.
Unstratified deposits which contain a hetrogeneous mixture of rock debris ranging in size from fine particles to huge boulders without any size assortment are called till, as already discussed under valley glacier.
The ice-sheets produce only three types of moraines as – Terminal moraines, Recessional moraines and Ground moraines. It is to be noted that the lateral and medial moraines which mainly occur in valley glaciers are absent in the continental ice-sheets.
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After the ice disappears the terminal moraine is seen as a chain of knobby hills interspersed with basin like hollows. Such a belt of terminal moraine is known as knob and kettle topography.
Terminal moraines are in the form of great curves and are produced due to the advance of great ice lobes. When two lobes come together the moraines get fused into a single moraine between two ice lobes. Such a deposit is known as an interlobate moraine.
The terminal, recessional and ground moraines have already been discussed under the depositional features produced by valley-glaciers.