Glacial Deposition Features: Drumlins and Eskers
This page continues the discussion of glacial deposition features, focusing on drumlins and eskers.
Drumlins
Drumlins are elongated hills made of till, formed by glacial deposition. The formation process includes:
- Glaciers carrying eroded material from highlands to lowlands
- Deposition of material as the glacier melts and loses energy
- Till building up around small obstacles under the glacier
- Streamlining of sediment as the glacier continues to move
Vocabulary: Drumlins have a steep 'stoss' slope facing up-valley and a gentle 'lee' slope facing down-valley.
Example: A notable example of a drumlin swarm can be found in Newport Bay.
Highlight: Drumlins often form in groups called swarms and can continue to be shaped by further ice movements after initial deposition.
Eskers
Eskers are meandering ridges formed by glacial meltwater streams. The formation process involves:
- Subglacial streams flowing through tunnels as the glacier melts
- Deposition of fluvio-glacial material on the channel bed
- Layered deposition with heavier material at the bottom
- Rounding of material due to further erosion by streams
- Remaining deposits after glacier retreat forming meandering ridges
Definition: Eskers are meandering ridges of stratified sand and gravel deposited by subglacial streams.
Highlight: Eskers flow down the valley towards the terminal moraine, providing evidence of past glacial meltwater channels.
The page includes diagrams illustrating the formation of terminal moraines and the structure of glaciers, enhancing understanding of these complex processes.
