Drumlinization

Drumlinization is a glacial geomorphological process responsible for the formation of drumlins. These are elongated, streamlined hills formed by the action of flowing ice. The process involves the deposition and subsequent molding of glacial till, a mixture of clay, silt, sand, gravel, and boulders. As a glacier moves, it picks up and transports this material. When conditions change, such as a decrease in ice velocity or the melting of the ice, the till is deposited.

The characteristic shape of a drumlin, with a blunt, stoss end facing the direction of ice flow and a tapering, lee end pointing down-ice, is a result of the ice's erosional and depositional capabilities. The stoss end is built up as till is deposited, and the ice flow then shapes and elongates this deposit. Material is plastered onto the upstream side, while the ice overrides and streamlines the downslope portion. The specific mechanisms of drumlin formation are still debated, with theories including subglacial meltwater deposition and ice overriding existing unconsolidated till. Drumlins often occur in groups, forming "drumlin fields," which provide valuable insights into past ice flow directions and the dynamics of the glacier that created them.