Aquifer Designated Area Figure 2. Figures Figure 1. Aquifer Designated Area Figure 2. Ice advances over area and gathers load by eroding bedrock. Later, at the base of the ice, rock fragments are deposited to form till.
Ice begins to melt.
Stagnant ice melts. Ice-contact deposits slope toward center of valley. A glacial lake forms in which clay and silt accumulate. Glacial lake is filled with sediment or is drained. Glacial streams flow over surface of lake deposits and lay down sand and gravel deposits.